Systems and methods for virtual reality, augmented reality, and / or mixed reality based visual function testing based on optokinetic reflex

Abstract

Systems and methods for visual function testing are disclosed. A method may include providing (e.g., rendering and displaying) an animated graphic where spaced-apart shapes appear to move with respect to (e.g., over) a background to a subject. Movement of one or both eyes of the subject may be tracked, for example, to determine when a subject exhibits an optokinetic reflex in one or both eyes. Contrast of the animated graphic may be changed (e.g., reduced or increased). For example, contrast between the spaced-apart shapes and the background may be changed. The method may include detecting and / or quantifying the optokinetic reflex of the subject in response to the change in contrast. For example, the method may include determining a contrast at which the optokinetic reflex begins or ceases. The animated graphic may be provided using a virtual - and / or augmented- and / or mixed-reality device, such as a VR headset with eye tracking capability.

Description

SYSTEMS AND METHODS FOR VIRTUAL REALITY, AUGMENTED REALITY, AND / OR MIXED REALITY BASED VISUAL FUNCTION TESTING BASED ON OPTOKINETIC REFLEXPRIORITY APPLICATION

[0001] The present application claims priority to and benefit of U.S. Provisional Patent Application No. 63 / 654,898, filed on May 31, 2024, the disclosure of which is hereby incorporated by reference herein in its entirety.TECHNICAL FIELD

[0002] This disclosure relates generally to visual function testing based on the optokinetic reflex.BACKGROUND

[0003] Visual function testing often relies on a subject’s ability to perceive something displayed in a field of view of the subject. A graphic, whether tangible (e.g., printed) or virtual (e.g., on a screen), is placed in a field of view of a subject and the subject’s ability to see the graphic is determined. Various tests can be performed to assess a subject’s visual function in this manner, including visual acuity and contrast sensitivity tests. Contrast sensitivity is an aspect of visual function whose importance is independent of visual acuity. For example, a subject may have a healthy visual acuity but poor contrast sensitivity and therefore still perform poorly on one or more visual function tests. Contrast sensitivity is often tested by perceptual methods, where a graphic with spatially and / or temporally variable contrast is presented to a subject and it is determined the extent to which the change in contrast affects the subject’s ability to perceive the graphic. There remains a need, however, for new and improved visual function tests, including contrast sensitivity tests.SUMMARY

[0004] Disclosed herein are, inter alia, systems and methods for performing visual function tests that rely primarily on reflex responses rather than primarily on conscious perceptual responses of a subject. Reflex responses are automatic and essentially immediate, whereasconscious perception involves the cerebral cortex and is slower. Moreover, testing based on conscious perception may be prone to error, for example either from a subject (e.g., because the subject did not understand instructions or accurately indicate perception) or from a testing setup (e.g., due to calibration issues). Similarly, standard perimetry testing, where a patient pushes a button to confirm visibility in a specific point, is also error prone. Although techniques can be used to compensate, for example by testing multiple times, such techniques drastically increase testing time, which is undesirable. The optokinetic reflex (also called optokinetic response or optokinetic nystagmus), in particular, may be exploited to test visual function, including contrast sensitivity, of a subject.

[0005] Optokinetic reflex -based tests described herein may provide advantages over more perceptual-based tests, for example, because visual function tests that rely primarily on conscious perception may be limited by the resolution, sensitivity, calibration, and / or quality of eye tracking that can be achieved, for example, using a virtual- and / or augmented- and / or mixed-reality device (e.g., VR headset) with eye tracking capability. For example, a perceptual contrast sensitivity vision test may require the eye tracking system to accurately detect a specific gaze location as a function of time. By contrast, in certain embodiments, optokinetic reflex tests described herein do not require pinpoint eye-gaze identification accuracy to confirm the eye is following a specific graphical target presented to the subject. Rather, the eye tracker detects when the subject begins and / or ends the repetitive, involuntary eye movements characterized as optokinetic nystagmus (e.g., well-characterized horizontal, vertical, or circular nystagmus eye movements). Using optokinetic reflex as the basis for a visual function test (e.g., assessment) method can also mitigate any issues that may be caused by poor visual acuity of a subject.

[0006] A test that includes tracking a point of gaze of a subject may produce unusable or otherwise poor results if eye tracking quality is inaccurate. In certain subjects (e.g., certain demographics of subjects), accurate eye tracking may be difficult, even where professional grade eye tracking (e.g., integrated in a professional grade virtual- and / or augmented- and / or mixed- reality device) is used. Using a test based primarily based on reflex response, such as the optokinetic reflex, will, in general, be less sensitive to quality of eye tracking and therefore may produce improved results, especially where lower grade hardware (e.g., consumer, rather than professional, devices) is used. For example, an eye and pupil and motion thereof may still need to be detected but there may be no need to detect or track point of gaze. Thus, in some embodiments,a test can be performed without calibration, such as eye tracking calibration or other user-related (e.g., subject related calibration, of a virtual- and / or augmented- and / or mixed-reality device, for example because there is no need to track a point of gaze of a subject. In some embodiments, consumer grade hardware may be used and still achieve suitable test results, for example for diagnostic purposes. Moreover, tests can be conducted quickly (e g., in no more than 90 seconds, no more than 60 seconds, no more than 30 seconds, no more than 20 seconds, or no more than 10 seconds).

[0007] Methods disclosed herein may test optokinetic reflex of a subject. Methods disclosed herein may be for performing a test of optokinetic reflex of a subject. Methods disclosed herein may test visual function. Methods disclosed herein may be for performing a visual function test. Methods disclosed herein may test contrast sensitivity. Methods disclosed herein may be for performing a contrast sensitivity test. Methods disclosed herein may test photostress recovery, for example if a bright (e.g., white) screen is initially provided (e g., rendered and displayed) to a subject. Methods disclosed herein may be for performing a photostress recovery test. A method may test a combination of these (e.g., simultaneously or in sequence), for example a method may test optokinetic reflex and (e.g., other) visual function. A method that tests, or is for performing a test of, contrast sensitivity and / or photostress recovery may rely on optokinetic reflex of a subject. A method that tests, or is for performing a test of, visual function may rely on optokinetic reflex of a subject. A method may be, or be for performing, an optokinetic-reflex-based test, such as an optokinetic-reflex -based visual function test.

[0008] In some embodiments, a subject exhibits an optokinetic reflex in one or both eyes during at least a portion of a method, for example due to one or more graphics and / or widgets provided (e.g., displayed) by a virtual- and / or augmented- and / or mixed-reality device. An optokinetic reflex may be induced, or caused to be ceased, using a virtual- and / or augmented- and / or mixed-reality device. An optokinetic reflex may be exhibited (e.g., induced) due to an animated graphic, for example that includes spaced-apart shapes [e.g., disposed over (e.g., overlaid on) or in (e g., interspersed within) a background and / or disposed within a frame (e.g., window)]. Spaced-apart shapes may appear to move with respect to (e.g., over) a background, which itself may appear to be still or in motion. Spaced-apart shapes may appear to move with respect to (e.g., inside of) a frame (e.g., window) (e.g., and also appear to move with respect to a background, which itself may appear inside of the frame). An animated graphic may appear to move based onit being framed (e.g., like a view through a window of a moving vehicle). An optokinetic reflex may be exhibited (e.g., induced) due a contrast widget disposed over (e.g., overlaid on) or in (e.g., interspersed within) a background graphic, for example where the contrast widget and / or the background graphic appear to be in motion (e.g., motion relative to each other). A background graphic may be a rendered and displayed background graphic (e.g., of a scene, such as a nature scene). A background graphic may be a live view or virtual rendering of a field of view of a subject provided to a subject, for example provided using an augmented- and / or mixed-reality device. A contrast widget may include spaced-apart shapes, for example as a grating. Such shapes, backgrounds, background graphics, and / or contrast widgets may be rendered and displayed using a virtual- and / or augmented- and / or mixed-reality device.

[0009] Contrast in a field of view (e.g., of at least a portion of a field of view) of a subject may be progressively changed during a method. Such change in contrast may be made in order to determine when a subject begins to exhibit or ceases to exhibit an optokinetic reflex in one or both eyes, which may therefore indicate a contrast sensitivity of the subject. Changing contrast may cause a subject to begin to have or cease to have an optokinetic reflex in one or both eyes. Contrast may be progressively changed by increasing contrast or by reducing contrast. Contrast may be continuously progressively changed or progressively changed in a series of discrete steps. Contrast may be changed in any number of ways, including, for example, by changing a size, color, and / or opacity of spaced-apart shapes that contribute to causing an optokinetic reflex and / or by graying or de-graying at least a portion of a field of view of a subject.

[0010] Spatial frequency of spaced-apart shapes (e.g., of a contrast widget or animated graphic) may be progressively changed during a method. Such change in spatial frequency may be made in order to determine contrast sensitivity of a subject, for example by separately progressively changing contrast while progressively changing spatial frequency. In this way, different combinations of spatial frequency and contrast may be tested. Contrast sensitivity may be determined and / or recorded in a two-dimensional measurement space, for example a contrast sensitivity space where contrast (e.g., contrast sensitivity) represents one dimension and spatial frequency represents the other dimension. Spatial frequency (e.g., in combination with contrast) may cause a subject to begin to have or cease to have an optokinetic reflex in one or both eyes. For example, a subject may begin to exhibit an optokinetic reflex at a certain contrast for one spatial frequency but not another or for a certain spatial frequency at one contrast but not another.Spatial frequency may be progressively changed by increasing spatial frequency or by reducing spatial frequency. Spatial frequency may be continuously progressively changed or progressively changed in a series of discrete steps. Spatial frequency may be changed in any number of ways by, for example by changing size (e.g., thickness) of, distance between (e.g., spacing of), and / or relative speed of spaced-apart shapes.

[0011] Eye movement of one or both eyes of a subject may be tracked (e.g., automatically) during a method. Eye movement may be tracked to monitor an optokinetic reflex of a subject in one or both eyes. Eye movement may be tracked to determine onset or cessation of an optokinetic reflex in one or both eyes of a subject and / or for how long a subject exhibits an optokinetic reflex in one or both eyes. Eye movement may be tracked, for example using eye tracking capability of a virtual- and / or augmented- and / or mixed-reality device, while a subject is exhibiting an optokinetic reflex in one or both eyes. Eye movement may be tracked, for example using eye tracking capability of a virtual- and / or augmented- and / or mixed-reality device, during changing contrast in a field of view of a subject. Eye movement may be tracked, for example using eye tracking capability of a virtual- and / or augmented- and / or mixed-reality device, in response to a graphic and / or a widget [e.g., in response to a contrast widget disposed over (e.g., overlaid on) or in (e.g., interspersed within) a background]. Tracking may include capturing images of one or both eyes of a subject, for example as still images or frames of a video image.

[0012] Tracking eye movement be used to determine an optokinetic nystagmus profile for one or both eyes of a subject. An optokinetic nystagmus profile may indicate (e g., show or illustrate) onset and / or cessation of an optokinetic reflex over time. An optokinetic nystagmus profile may be compared to a test protocol and / or record of what was shown to a subject. One or more characteristics may be determined based on such comparison, including, for example, (i) for at least one point in time, whether a subject can see a contrast widget and / or a graphic, (ii) when an optokinetic reflex in one or both eyes of a subject begins and / or ceases, (iii) a contrast level at which an optokinetic reflex in the one or both eyes of the subject begins and / or ceases, or (iv) a combination thereof. A contrast level determined by such a comparison may be, for example, a relative contrast level between the background graphic and the contrast widget, a contrast level (e.g., opacity) of the contrast widget, or a gray level of at least a portion of a field of view of the subject.

[0013] Various advantages of optokinetic reflex -based tests described herein include, for example, providing efficient, simple testing of the subject without requiring the subject to perform any unpleasant or tedious visual task. This may be particularly beneficial for very young subjects, senior citizens, or other subjects for whom such tasks may be difficult or confusing. In certain embodiments, the animated graphics are visually interesting and designed to engage the subject, without requiring concentration. Also, as discussed previously, a simpler eye-tracking system (hardware and software) can be used with optokinetic reflex -based tests described herein. An eyetracking system may detect when the subject begins and / or ends the repetitive, involuntary eye movements characterized as optokinetic nystagmus (e.g., well-characterized horizontal, vertical, or circular nystagmus eye movements) - the system does not need to accurately track the subject’s point-of-gaze over time.

[0014] In some aspects, the present disclosure is directed to a method for performing a visual function test on a subject (e.g., a contrast sensitivity test and / or a photostress recovery test) (e.g., an optokinetic reflex test) (e.g., using a virtual- and / or augmented- and / or mixed-reality device, e.g., a VR headset with eye tracking capability). The method may include rendering and displaying (e g., on a head-mounted {e.g. face-mounted} display of the VR headset) to the subject, by a processor of a computing device, an animated graphic in a field of view of the subject (e.g., displaying the animated graphic in a virtual and / or augmented scene in the field of view). The method may include during display of the animated graphic, (e.g., automatically) tracking movement (e.g., by the processor, e.g., using eye tracking software and / or hardware, e.g., using the VR headset with eye tracking capability, e.g., using an eye tracking camera with associated software and / or illumination source) of one or both eyes of the subject to detect and / or quantify an optokinetic reflex of the subject in response to the animated graphic [e.g., wherein the tracking comprises capturing images of one or both eyes of the subject (e.g., as still images or video)].

[0015] In some embodiments, the animated graphic comprises a series of spaced-apart shapes (e.g., a series of vertical lines or rectangles, e.g., a grating) that appear to move (e.g., move together) in a particular direction (e.g., a horizontal direction or a vertical direction) (e.g., wherein the spaced-apart shapes are translucent) (e.g., wherein the spaced-apart shapes have an opacity in a range of 20%-80%) [e.g., wherein the spaced-apart shapes are grayscale (e.g., black)]. In some embodiments, the series of spaced-apart shapes appear to move with respect to (e.g., over) a background [e.g., a stationary background (e.g., over a scenic graphic that serves as the stationarybackground)] (e.g., wherein the background is a live view or virtual rendering of a field of view of the subject outside of an augmented- and / or mixed-reality device). In some embodiments, the series of spaced-apart shapes appear to move with respect to (e.g., inside of) a stationary frame (e.g., that appears as window) (e.g., wherein the background is a live view or virtual rendering of a field of view of the subject outside of an augmented- and / or mixed-reality device).

[0016] In some embodiments, the method includes rendering and displaying the animated graphic with progressively changing (e.g., reducing or increasing) contrast (e.g., between the series of spaced-apart shapes and the background) (e g., wherein contrast is progressively changed continuously or in discrete steps) (e.g., at least until the subject ceases to have an optokinetic reflex in response to the motion) (e.g., until the background and the spaced-apart shapes are indistinguishable). In some embodiments, the rendering and displaying the animated graphic with the progressively changing contrast comprises changing a size of the spaced-apart shapes [e.g., by reducing or expanding at least one dimension (e.g., width) of the spaced-apart shapes (e.g., until the spaced-apart shapes disappear or become contiguous, respectively)]. In some embodiments, the rendering and displaying the animated graphic with the progressively changing contrast comprises changing an opacity of the spaced-apart shapes and / or the background [e.g., by reducing an opacity of the spaced-apart shapes (e.g., until the shapes become transparent)]. In some embodiments, the rendering and displaying the animated graphic with the progressively changing contrast comprises simultaneously progressively graying or de-graying the background and / or the spaced-apart shapes [e.g., until an entire field of view of the subject becomes gray (e.g., uniformly gray)] [e.g., uniformly graying (e.g., both the background and the spaced-apart shapes)]. In some embodiments, the rendering and displaying the animated graphic with the progressively changing contrast comprises progressively graying or de-graying at least a portion of a field of view of the subject [e.g., until an entire field of view of the subject becomes gray (e.g., uniformly gray)] (e.g., uniformly graying) (e.g., at least until the subject ceases to have an optokinetic reflex in response to the motion). In some embodiments, the rendering and displaying the animated graphic with the progressively changing contrast comprises changing at least one color of the spaced-apart shapes to correspond to one or more colors of the background and / or changing at least one color of the background to correspond to one or more colors of the spaced-apart shapes. In some embodiments, the rendering and displaying the animated graphic with the progressively changing contrastcomprises lightening and / or darkening the background, the spaced-apart shapes, or both to reduce the contrast therebetween.

[0017] In some embodiments, the method includes rendering and displaying, by the processor, progressively changing spatial frequency of spaced-apart shapes in the animated graphic while separately progressively changing the contrast (e.g., changing thickness of the spaced-apart shapes while progressively greying the background graphic and / or contrast widget) [e.g., changing distance between (e.g., spacing of) the spaced-apart shapes while progressively greying the background graphic and / or contrast widget] (e.g., changing thickness of the spaced- apart shapes while progressively greying at least a portion of a field of view of the subject) (e.g., changing relative speed of the spaced-apart shapes while progressively greying at least a portion of a field of view of the subject).

[0018] In some embodiments, the method includes rendering and displaying to the subject, by the processor, a progressively changing (e.g., a reducing or an increasing): (i) relative speed of the spaced-apart shapes (e.g., a speed of the spaced-apart shapes in relation to the static background), and / or (ii) distance between spaced-apart shapes, and / or (iii) size (e.g., thickness) of the spaced-apart shapes (e.g., thickness of stripes) [e.g., one, two, or all three of the preceding (i), (ii), and (iii)] (e.g., wherein the progressively changing relative speed and / or distance between spaced-apart shapes and / or size of the spaced-apart shapes is rendered in discrete steps) (e.g., wherein the progressively changing relative speed and / or distance between spaced-apart shapes and / or size of the spaced-apart shapes is rendered as a continuous change, e.g., gradual change) (e.g., wherein the progressive changing of the relative speed and / or distance between spaced-apart shapes and / or size of the spaced-apart shapes results in a changing spatial frequency between the background and the spaced-apart shapes).

[0019] In some embodiments, the method includes progressively changing, by the processor, a spatial frequency of the spaced-apart shapes (e.g., by changing thickness of, relative speed of, and / or distance between (e.g., spacing of) the spaced-apart shapes) while tracking the movement of one or both eyes of the subject.

[0020] In some embodiments, the method includes rendering and displaying, by the processor, the animated graphic at a plurality of combinations of (i) contrast (e.g., of the contrast widget relative to the background graphic) and (ii) spatial frequency of the spaced-apart shapes while tracking the movement of one or both eyes of the subject. In some embodiments, the methodincludes determining and / or recording, by the processor, a contrast and spatial frequency for each of the combinations at which the subject begins to have or ceases to have an optokinetic reflex in response to appearance of motion. In some embodiments, the method includes rendering and displaying, by the processor, the animated graphic while progressively changing both contrast of the spaced-apart shapes relative to the background and spatial frequency of the spaced-apart shapes, also while tracking the movement of one or both eyes of the subject.

[0021] In some embodiments, automatically determining, by the processor, when the optokinetic reflex of the subject ceases or begins (e.g., automatically determining when the contrast is low enough for the optokinetic reflex to cease or high enough for the optokinetic reflex to begin) based on the tracking.

[0022] In some embodiments, the method includes determining, by the processor, an optokinetic nystagmus profile for the subject based at least in part on the tracked eye movement.

[0023] In some embodiments, the method includes determining a contrast sensitivity function for the subject based on the detection and / or quantification of the optokinetic reflex of the subject.

[0024] In some embodiments, the method includes determining an abnormality (e.g., an abnormal optokinetic reflex) or condition (e.g., retinal condition) of the subject based at least in part on the tracked eye movement.

[0025] In some embodiments, the animated graphic is rendered and displayed using a virtual- and / or augmented- and / or mixed-reality device [e.g., on a head-mounted (e.g., facemounted) display of a VR headset] (e.g., wherein the device comprises the processor) [e.g., a consumer device (e.g., VR headset)]. In some embodiments, the device has eye tracking capability and the tracking movement of one or both eyes of the subject is performed with the device.

[0026] In some embodiments, the method is performed without calibration (e.g., without calibrating the device) (e.g., without eye tracking calibration) [e.g., without any user-related (e.g., subject-related) calibration]. In some embodiments, the method is performed without determining a point of a gaze of the subject.

[0027] In some aspects, the present disclosure is directed to a method for performing a visual function test on a subject (e.g., a contrast sensitivity test and / or a photostress recovery test) (e.g., an optokinetic reflex test) (e.g., using a virtual- and / or augmented- and / or mixed-reality device, e.g., a VR headset with eye tracking capability). The method may include providing (e.g.,rendering and displaying) to a subject, by a processor, a background graphic [e.g., a scenic graphic (e.g., of a nature scene, a background scene, or any other scene, realistic or abstract] (e.g., a background color and / or uniform background) (e.g., wherein the background graphic is a live view or virtual rendering of a field of view of the subject outside of an augmented- and / or mixed-reality device). The method may include, during provision (e.g., display) of the background graphic, rendering and displaying to the subject, by the processor, a contrast widget comprising a plurality of spaced-apart shapes [e.g., lines or rectangles (e.g., a series of lines or rectangles)] (e.g., a grating) disposed over (e.g., overlaid on) or in (e.g., interspersed within) the background graphic such that the contrast widget appears to be in motion (e.g., relative motion to the background graphic) (e.g., in fast, medium, or slow motion, e.g., in a horizontal or vertical direction). The method may include tracking (e.g., automatically) (e.g., using the processor or a second processor) [e.g., using eye tracking software and / or hardware (e.g., using a VR headset with eye tracking capability) (e.g., using an eye tracking camera, e.g., with associated software and / or illumination source)] movement of one or both eyes of the subject in response to the contrast widget disposed over or in the background graphic [e.g., wherein the tracking comprises capturing images of one or both eyes of the subject (e.g., as still images or video)].

[0028] In some embodiments, tracking the movement of the one or both eyes of the subject comprises tracking (e.g., detecting and / or quantifying) an optokinetic reflex (optokinetic nystagmus) of the subject caused by the apparent motion (e.g., animation of the contrast widget). In some embodiments, the background graphic is animated (e.g., appears to the subject to be in motion) [e.g., and the contrast widget is not animated (e.g., appears to the subject to be still)] [e.g., is provided in a framing graphic (e.g., representing a window)]. In some embodiments, the contrast widget is animated (e.g., appears to the subject to be in motion) [e.g., and the background graphic is not animated (e.g., appears to the subject to be still)] [e.g., is provided in a framing graphic (e.g., representing a window)]. In some embodiments, the motion is of a sufficient speed as to induce an optokinetic reflex in the subject. In some embodiments, the background graphic appears stationary behind a moving series of lines or rectangles (e.g., a moving grating).

[0029] In some embodiments, the method includes rendering and displaying to the subject, by the processor, progressively changing (e.g., reducing or increasing) contrast between the background graphic and the contrast widget while tracking the movement of one or both eyes of the subject (e.g., wherein contrast is progressively changed continuously or in discrete steps) (e.g.,at least until the subject ceases to have an optokinetic reflex in response to the motion) (e.g., until the background graphic and the contrast widget are indistinguishable). In some embodiments, the rendering and displaying the progressively changing contrast comprises changing a size of the spaced-apart shapes [e.g., by reducing or expanding at least one dimension (e.g., width) of the spaced-apart shapes (e.g., until the spaced-apart shapes disappear or become contiguous, respectively)]. In some embodiments, the rendering and displaying the progressively changing contrast comprises changing an opacity of the spaced-apart shapes and / or the background graphic [e.g., by reducing an opacity of the spaced-apart shapes (e.g., until the shapes become transparent)]. In some embodiments, the rendering and displaying the progressively changing contrast comprises simultaneously progressively graying or de-graying the background graphic and / or the contrast widget [e.g., until an entire field of view of the subject becomes gray (e.g., uniformly gray)] [e.g., uniformly graying (e.g., both the background graphic and the contrast widget)]. In some embodiments, the rendering and displaying the progressively changing contrast comprises progressively graying or de-graying at least a portion of a field of view of the subject [e.g., until an entire field of view of the subject becomes gray (e.g., uniformly gray)] (e.g., uniformly graying). In some embodiments, the rendering and displaying the progressively changing contrast comprises changing at least one color of the contrast widget to correspond or no longer correspond to one or more colors of the background graphic and / or changing at least one color of the background graphic to correspond to one or more colors of the contrast widget (e.g., until the background graphic and the contrast widget are indistinguishable). In some embodiments, the rendering and displaying the progressively changing contrast comprises lightening and / or darkening the background graphic, the contrast widget, or both to change (e.g., reduce or increase) the contrast therebetween.

[0030] In some embodiments, the method includes recording, by the processor, a period of time that elapsed before the subject has or no longer has an optokinetic reflex in response to the contrast widget disposed over or in the background graphic and / or when the subject has or no longer has an optokinetic reflex in response to the contrast widget disposed over or in the background graphic.

[0031] In some embodiments, the rendering and displaying the progressively changing contrast comprises progressively graying or de-graying the background graphic and / or the contrast widget.

[0032] In some embodiments, the contrast progressively changes over a period of no more than 20 seconds (e.g., no more than 10 seconds or no more than 5 seconds).

[0033] In some embodiments, the method includes rendering and displaying, by the processor, progressively changing spatial frequency of the spaced-apart shapes while separately progressively changing the contrast (e.g., changing thickness of the spaced-apart shapes while progressively greying the background graphic and / or contrast widget) [e.g., changing distance between (e.g., spacing of) the spaced-apart shapes while progressively greying the background graphic and / or contrast widget] (e g., changing thickness of the spaced-apart shapes while progressively greying at least a portion of a field of view of the subject) (e.g., changing relative speed of the spaced-apart shapes while progressively greying at least a portion of a field of view of the subject).

[0034] In some embodiments, tracking the movement of one or both eyes comprises determining, by the processor, when an optokinetic reflex of the subject begins and / or ceases (e.g., in response to the change of contrast) (e.g., automatically determining when the contrast is low enough for the optokinetic reflex to cease).

[0035] In some embodiments, the method includes recording, by the processor, a contrast (e.g., a relative contrast between the background graphic and the contrast widget) [e.g., in a two- dimensional measurement space (e.g., having contrast dimension and a spatial frequency dimension)] at which the subject begins to have or no longer has an optokinetic reflex.

[0036] In some embodiments, the method includes rendering and displaying to the subject, by the processor, a progressively changing (e.g., a reducing or an increasing): (i) relative speed of the contrast widget (e.g., a speed of the animated contrast widget in relation to the static background graphic), and / or (ii) distance between spaced-apart shapes of the (e.g., animated) contrast widget, and / or (iii) size (e.g., thickness) of the spaced-apart shapes of the (e.g., animated) contrast widget (e.g., thickness of stripes) [e.g., one, two, or all three of the preceding (i), (ii), and (iii)] (e.g., wherein the progressively changing relative speed and / or distance between spaced-apart shapes and / or size of the spaced-apart shapes is rendered in discrete steps) (e.g., wherein the progressively changing relative speed and / or distance between spaced-apart shapes and / or size of the spaced-apart shapes is rendered as a continuous change, e.g., gradual change) (e.g., wherein the progressive changing of the relative speed and / or distance between spaced-apart shapes and / orsize of the spaced-apart shapes results in a changing spatial frequency between the background graphic and the contrast widget).

[0037] In some embodiments, the method includes progressively changing, by the processor, a spatial frequency of the contrast widget [e.g., by changing size (e.g., thickness) of, relative speed of, and / or distance between (e.g., spacing of) the spaced-apart shapes] while tracking the movement of one or both eyes of the subject.

[0038] In some embodiments, the method includes rendering and displaying, by the processor, the background graphic and the contrast widget such that the contrast widget appears to be in motion at a plurality of combinations of (i) contrast (e.g., of the contrast widget relative to the background graphic) and (ii) spatial frequency of the spaced-apart shapes while tracking the movement of one or both eyes of the subject. In some embodiments, the method includes determining and / or recording, by the processor, a contrast and spatial frequency for each of the combinations at which the subj ect begins to have or ceases to have an optokinetic reflex in response to appearance of motion.

[0039] In some embodiments, the method includes providing and / or rendering and displaying, by the processor, the background graphic and the contrast widget such that the contrast widget appears to be in motion while progressively changing both contrast of the contrast widget relative to the background graphic and spatial frequency of the spaced-apart shapes, also while tracking the movement of one or both eyes of the subject.

[0040] In some embodiments, the method includes determining a contrast sensitivity function for the subject based on the tracking of movement of one or both eyes of the subject.

[0041] In some embodiments, the method includes determining, by the processor, an optokinetic nystagmus profde for the subject based at least in part on the tracking. In some embodiments, the method includes comparing, by the processor, one or more characteristics of the motion to the nystagmus profde. In some embodiments, the method includes determining, by the processor, (i) for at least one point in time, whether the subject can see the contrast widget, (ii) when an optokinetic reflex in the one or both eyes of the subject begins and / or ceases, (iii) a contrast level [e.g., a relative contrast level between the background graphic and the contrast widget, a contrast level (e.g., opacity) of the contrast widget, or a gray level of at least a portion of a field of view of the subject] (e.g., a contrast for a specific spatial frequency) (e.g., at a spatial frequency of spaced-apart shapes in the contrast widget) [e.g., in a two-dimensional measurementspace (e.g., having contrast dimension and a spatial frequency dimension)] at which an optokinetic reflex in the one or both eyes of the subject begins and / or ceases, or (iv) a combination thereof, based at least in part on a result of the comparing (e.g., based on a contrast level between the background graphic and the contrast widget determined by the comparison). In some embodiments, the method includes determining (e.g., by the processor) an abnormality or condition (e.g., retinal condition) of the subject based at least in part on a result of the comparing.

[0042] In some embodiments, the method includes determining (e.g., by the processor) an abnormality (e.g., an abnormal optokinetic reflex) or condition (e.g., retinal condition) of the subject based at least in part on the tracking.

[0043] In some embodiments, the method includes the appearance of motion occurs over a period of time of no more than 20 seconds (e.g., no more than 10 seconds or no more than 5 seconds).

[0044] In some embodiments, the motion is a unidirectional motion (e.g., in a horizontal or vertical direction) (e.g., wherein the contrast widget appears to move in a horizontal or vertical direction over the background graphic while the background graphic remains stationary). In some embodiments, the motion is a horizontal motion.

[0045] In some embodiments, the spaced-apart shapes are translucent (e.g., have an opacity in a range of 20% - 80%). In some embodiments, the spaced-apart shapes are grayscale (e.g., are dark). In some embodiments, the spaced-apart shapes are rendered and displayed with an initial luminance of at least 5 cd / m2and no more than 30 cd / m2. In some embodiments, the background graphic is provided (e.g., displayed) within a virtual and / or augmented scene in a field of view of the subject.

[0046] In some embodiments, the contrast widget is rendered and displayed and the background graphic is provided using a virtual- and / or augmented- and / or mixed-reality device [e.g., on a head-mounted (e.g., face-mounted) display of a VR headset] (e.g., wherein the device comprises the processor) [e.g., a consumer device (e.g., VR headset)]. In some embodiments, the device has eye tracking capability and the tracking movement of one or both eyes of the subject is performed with the device.

[0047] In some embodiments, the method is performed without calibrating the device (e.g., without eye tracking calibration) [e.g., without any user-related (e.g., subject-related) calibration].In some embodiments, the method is performed without determining a point of a gaze of the subject.

[0048] In some aspects, the present disclosure is directed to a method that includes changing (e.g., reducing or increasing) contrast in a field of view of a subject using a virtual- and / or augmented- and / or mixed-reality device such that one or both eyes of the subject begin to exhibit or cease to exhibit an optokinetic reflex; and tracking movement of the one or both eyes during the contrast change.

[0049] In some aspects, the present disclosure is directed to a method that includes inducing an optokinetic reflex in one or both eyes of a subject using a virtual- and / or augmented- and / or mixed-reality device (e.g., by displaying an animated graphic); changing (e.g., reducing or increasing) contrast in a field of view of the subject using the device while the one or both eyes are exhibiting the optokinetic reflex; and tracking movement of the one or both eyes during the contrast change. In some embodiments, tracking the movement comprises determining when the optokinetic reflex begins or ceases due to the contrast change in the field of view. In some embodiments, the virtual- and / or augmented- and / or mixed-reality device is a VR headset. In some embodiments, the device performs the tracking (e.g., has eye tracking capability).

[0050] In some aspects, the present disclosure is directed to a method that includes changing (e.g., reducing or increasing) contrast in a field of view of a subject such that one or both eyes of the subject begin to exhibit or cease to exhibit an optokinetic reflex; and tracking movement of the one or both eyes during the contrast change.

[0051] In some aspects, the present disclosure is directed to a method that includes inducing an optokinetic reflex in one or both eyes of a subject (e.g., with an animated graphic); changing (e.g., reducing or increasing) contrast in a field of view of the subject while the one or both eyes are exhibiting the optokinetic reflex; and tracking movement of the one or both eyes during the contrast change. In some embodiments, tracking the movement comprises determining when the optokinetic reflex begins or ceases due to the contrast change in the field of view. In some embodiments, the contrast is changed in the field of view (e g., and the optokinetic reflex is induced) using a virtual- and / or augmented- and / or mixed-reality device. In some embodiments, the device performs the tracking (e.g., has eye tracking capability).

[0052] In some aspects, the present disclosure is directed to a method for performing a visual function test on a subject (e.g., a contrast sensitivity test and / or a photostress recovery test)(e.g., an optokinetic reflex test) (e.g., using a virtual- and / or augmented- and / or mixed-reality device, e.g., a VR headset with eye tracking capability). The method may include rendering and displaying (e.g., on a head-mounted {e.g. face-mounted} display ofthe VR headset) to the subject, by a processor of a computing device, an animated graphic in a field of view of the subject (e.g., displaying the animated graphic in a virtual and / or augmented scene in the field of view). The method may include, during display of the animated graphic, (e.g., automatically) tracking movement (e.g., by the processor, e.g., using eye tracking software and / or hardware, e.g., using the VR headset with eye tracking capability, e.g., using an eye tracking camera with associated software and / or illumination source) of one or both eyes of the subject in response to the animated graphic [e.g., wherein the tracking comprises capturing images of one or both eyes of the subject (e.g., as still images or video)].

[0053] In some aspects, the present disclosure is directed to a system (e.g., a virtual- and / or augmented- and / or mixed-reality device system) comprising a processor and a memory having instructions stored thereon, the instructions executable by the processor to perform a method disclosed herein. In some embodiments, the system includes a virtual- and / or augmented- and / or mixed-reality device operable to be used in performance of the method (e.g., comprising the processor and the memory). In some embodiments, the device is a consumer VR headset with eye tracking capability.

[0054] In some aspects, the present disclosure is directed to a system for conducting a visual function test (e.g., an optokinetic reflex assessment) on a subject using a virtual- and / or augmented- and / or mixed-reality device (e.g., VR headset with eye tracking capability), the system comprising: a processor of a computing device; and a memory having instructions stored thereon, wherein the instructions, when executed by the processor, cause the processor to perform a method disclosed herein. In some embodiments, the system includes the virtual- and / or augmented- and / or mixed-reality device for performing the visual function test. In some embodiments, the device is a consumer VR headset. In some embodiments, the system includes an eye-tracking camera (e.g., wherein the headset comprises the eye-tracking camera). In some embodiments, the system includes an illumination source (e.g., wherein the headset comprises the illumination source).

[0055] In some embodiments, a method includes diagnosing the subject as having an eye condition based at least in part on a result of a visual function test [e.g., wherein the eyecondition is a member selected from the group consisting of diabetic retinopathy (e.g., with or without diabetic macular retinopathy), Stargardt disease, Leber hereditary optic neuropathy (LHON), retinitis pigmentosa, glaucoma, inner nuclear layer disease, geographic atrophy, and macular degeneration (e.g., age-related macular degeneration (AMD)) (e.g., dry age-related macular degeneration (dry AMD), wet age-related macular degeneration (wet AMD), and / or neovascular age-related macular degeneration (neovascular AMD))]. In some embodiments, a method includes monitoring an eye condition of the subject based at least in part on a result of the visual function test. In some embodiments, the monitoring comprises determining of a worsening severity of and / or a progressive worsening of the eye condition.

[0056] In some embodiments, a subject has an eye condition, and a method comprises monitoring the subject for progression of the eye condition based at least in part on a result of a visual function test [e.g., wherein the eye condition is a member selected from the group consisting of diabetic retinopathy (e.g., with or without diabetic macular retinopathy), Stargardt disease, Leber hereditary optic neuropathy (LHON), retinitis pigmentosa, glaucoma, inner nuclear layer disease, geographic atrophy, and macular degeneration (e.g., age-related macular degeneration (AMD)) (e.g., dry age-related macular degeneration (dry AMD), wet age-related macular degeneration (wet AMD), and / or neovascular age-related macular degeneration (neovascular AMD))].

[0057] In some embodiments, a method includes administering to the subject (a) a therapeutically effective amount of a therapeutic agent for treatment of a eye condition [e.g., wherein the therapeutic agent comprises (i) a vitamin supplement and / or mineral supplement selected from the group consisting of vitamin C, zinc, vitamin E, copper, beta-carotene, and combinations thereof, (ii) ranibizumab, (iii) faricimab, (iv) brolucizumab, (v) aflibercept, or (vi) pegaptanib, (vii) a complement inhibitor, (viii) a neuroprotective agent, (ix) an anti-inflammatory agent, (x) a free radical scavenger, (xi) an anti-apoptotic agent, (xii) an integrin modulator, (xiii) a gene therapy, and / or (xiv) a cell therapy] and / or (b) a therapeutic intervention for treatment of the eye condition (e.g., laser coagulation therapy) (e.g., based on a result of the visual function test) (e.g., based on the diagnosis and / or the monitoring).

[0058] In some embodiments, a method includes treating a subject that has been determined to have an eye condition and / or a worsening (e.g., progressive worsening) (e.g., worsening of severity) of an eye condition using a method disclosed herein, the methodcomprising administering to the subject (a) a therapeutically effective amount of a therapeutic agent for treatment of the eye condition [e.g., wherein the therapeutic agent comprises (i) a vitamin supplement and / or mineral supplement selected from the group consisting of vitamin C, zinc, vitamin E, copper, beta-carotene, and combinations thereof, (ii) ranibizumab, (iii) faricimab, (iv) brolucizumab, (v) aflibercept, or (vi) pegaptanib, (vii) a complement inhibitor, (viii) a neuroprotective agent, (ix) an anti-inflammatory agent, (x) a free radical scavenger, (xi) an anti-apoptotic agent, (xii) an integrin modulator, (xiii) a gene therapy, and / or (xiv) a cell therapy] and / or (b) a therapeutic intervention for treatment of the eye condition (e.g., laser coagulation therapy).

[0059] Any two or more of the features described in this specification, including in this summary section, may be combined to form implementations of the disclosure, whether specifically expressly described as a separate combination in this specification or not.

[0060] At least part of the methods, systems, and techniques described in this specification may be controlled by executing, on one or more processing devices, instructions that are stored on one or more non-transitory machine-readable storage media. Examples of non-transitory machine- readable storage media include read-only memory, an optical disk drive, memory disk drive, and random access memory. At least part of the methods, systems, and techniques described in this specification may be controlled using a computing system including one or more processing devices and memory storing instructions that are executable by the one or more processing devices to perform various control operations.DEFINITIONS

[0061] In order for the present disclosure to be more readily understood, certain terms used herein are defined below. Additional definitions for the following terms and other terms may be set forth throughout the specification.

[0062] Therapeutic agent: As used herein, the phrase “therapeutic agent” in general refers to any agent that elicits a desired pharmacological effect when administered to an organism. In some embodiments, an agent is considered to be a therapeutic agent if it demonstrates a statistically significant effect across an appropriate population. In some embodiments, the appropriate population may be a population of model organisms. In some embodiments, an appropriate population may be defined by various criteria, such as a certain age group, gender, geneticbackground, preexisting clinical conditions, etc. In some embodiments, a therapeutic agent is a substance that can be used to alleviate, ameliorate, relieve, inhibit, prevent, delay onset of, reduce severity of, and / or reduce incidence of one or more symptoms or features of a disease, disorder, and / or condition. In some embodiments, a “therapeutic agent” is an agent that has been or is required to be approved by a government agency before it can be marketed for administration to humans. In some embodiments, a “therapeutic agent” is an agent for which a medical prescription is required for administration to humans.

[0063] Therapeutically effective: As used herein, a therapeutically effective substance [e.g., therapeutic agent (e.g., pharmaceutical compound, for example in a formulation)] is one that produces the desired effect for which it is administered. In some embodiments, the term refers to an amount that is sufficient, when administered to a population suffering from or susceptible to a disease, disorder, and / or condition in accordance with a therapeutic dosing regimen, to treat the disease, disorder, and / or condition. In some embodiments, a therapeutically effective substance is one that, when administered in an appropriate amount, reduces the incidence and / or severity of, and / or delays onset of, one or more symptoms of the disease, disorder, and / or condition. Those of ordinary skill in the art will appreciate that the term "‘'therapeutically effective” does not in fact require successful treatment be achieved in a particular individual. Rather, a therapeutically effective amount may be that amount that provides a particular desired pharmacological response in a significant number of subjects when administered to patients in need of such treatment. In some embodiments, reference to a therapeutically effective amount may be a reference to an amount as measured in one or more specific tissues (e.g., a tissue affected by the disease, disorder or condition) or fluids (e.g., blood, saliva, serum, sweat, tears, urine, etc.). Those of ordinary skill in the art will appreciate that, in some embodiments, a therapeutically effective amount of a particular agent or therapy may be formulated and / or administered in a single dose. In some embodiments, a therapeutically effective agent may be formulated and / or administered in a plurality of doses, for example, as part of a dosing regimen.

[0064] Treatment. As used herein, the term “treatment” (also “treat” or “treating”) refers to any administration of a therapeutic compound or therapeutic procedure (e.g., surgical intervention) that partially or completely alleviates, ameliorates, relives, inhibits, delays onset of, reduces severity of, and / or reduces incidence of one or more symptoms, features, and / or causes of a particular condition (e.g., disease or disorder). In some embodiments, such treatment may be ofa subject who does not exhibit signs of the relevant condition (e.g., disease or disorder) and / or of a subject who exhibits only early signs of the condition (e.g., disease or disorder). Alternatively or additionally, such treatment may be of a subject who exhibits one or more established signs of the relevant d condition (e.g., disease or disorder). In some embodiments, treatment may be of a subject who has been diagnosed as suffering from the relevant condition (e.g., disease or disorder). In some embodiments, treatment may be of a subject known to have one or more susceptibility factors that are statistically correlated with increased risk of development of the relevant condition (e.g., disease or disorder).

[0065] Subject: As used herein “a subject” is a human. In some embodiments, a subject is or may be suffering from a relevant condition (e.g., disease or disorder), for example of the eye (e.g., in one or both eyes). In some embodiments, a subject is susceptible to a condition (e.g., disease or disorder), such as an eye condition. In some embodiments, a subject displays one or more symptoms or characteristics of a condition (e.g., disease or disorder). In some embodiments, a subject does not display any symptom or characteristic of a condition (e.g., disease or disorder). In some embodiments, a subject is someone with one or more features characteristic of susceptibility to or risk of a condition (e.g., disease or disorder). In some embodiments, a subject is a patient. In some embodiments, a subject is an individual to whom diagnosis and / or a therapeutic agent is, may be, and / or has been administered. A subject may be diagnosed with and / or monitored for an eye condition. An eye condition of a subject may be monitored. An eye condition may affect one or both eyes of a subject. In some embodiments, a condition is an eye condition, such as, for example, diabetic retinopathy (e.g., with or without diabetic macular retinopathy), Stargardt disease, Leber hereditary optic neuropathy (LHON), retinitis pigmentosa, glaucoma, inner nuclear layer disease, geographic atrophy, and age-related macular degeneration (AMD) (e.g., intermediate age-related macular degeneration (intermediate AMD), dry age-related macular degeneration (dry AMD), wet age-related macular degeneration (wet AMD), and / or neovascular age-related macular degeneration (neovascular AMD)). Other eye conditions that affect sight (e.g., visual function) are known in the art.

[0066] Administration: As used herein, the term “administration” typically refers to the administration of a composition to a subject or system. Those of ordinary skill in the art will be aware of a variety of routes that may, in appropriate circumstances, be utilized for administration to a subject, for example a human. For example, in some embodiments, administration may beocular, oral, intravenous, parenteral, etc. In some embodiments, administration may involve dosing that is intermittent (e.g., a plurality of doses separated in time) and / or periodic (e.g., individual doses separated by a common period of time) dosing. In some embodiments, administration may involve continuous dosing (e.g., perfusion) for at least a selected period of time.BRIEF DESCRIPTION OF THE DRAWINGS

[0067] The present teachings described herein will be more fully understood from the following description of various illustrative embodiments, when read together with the accompanying drawings. It should be understood that the drawing described below is for illustration purposes only and is not intended to limit the scope of the present teachings in any way. The foregoing and other objects, aspects, features, and advantages of the disclosure will become more apparent and may be better understood by referring to the following description taken in conjunction with the accompanying drawings, in which:

[0068] Figs. 1A-1J illustrate a visual function test based on optokinetic reflex, according to illustrative embodiments of the present disclosure;

[0069] Fig. IK illustrates a view that includes output of an eye tracking camera during the test illustrated by Figs. 1A-1J that may be shown to a test operator, according to illustrative embodiments of the present disclosure;

[0070] Fig. IL illustrates a contrast sensitivity function against which performance of a subject can be compared, according to illustrative embodiments of the present disclosure;

[0071] Figs. 2A-2B illustrate different types of apparent motion that may occur in a test, according to illustrative embodiments of the present disclosure; and

[0072] Figs. 3A-3C illustrate progressive reduction in contrast by different mechanisms, according to illustrative embodiments of the present disclosure;

[0073] Figs. 4A-4C are schematic diagrams illustrating components of a VR headset with eye tracking capability, for use in the systems and methods described herein, according to illustrative embodiments of the present disclosure;

[0074] Fig. 5 is a block diagram of an example network environment for use in the methods and systems described herein, according to illustrative embodiments of the present disclosure; and

[0075] Fig. 6 is a block diagram of an example computing device and an example mobile computing device, for use in illustrative embodiments of the present disclosure.DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

[0076] Disclosed herein are, inter alia, methods for testing (e.g., assessing) and / or detecting visual function and systems for implementing such methods. In some embodiments, a method [e.g., a visual function test (e.g., visual function assessment)] may rely on the optokinetic reflex. For example, a method (e.g., test) may be based on when a subject exhibits an optokinetic reflex in one or both eyes, for example when an optokinetic reflex begins and / or ceases. A visual function test may therefore be a reflex-based visual function test. As described further subsequently, in some embodiments, a method may be used to test sensitivity of a subject to contrast and therefore may be a reflex-based contrast sensitivity test. In some embodiments, a virtual- and / or augmented- and / or mixed-reality device (e.g., with eye tracking capability) may be used to perform a method (e.g., a visual function test). In some embodiments, a visual function test may be performed without calibrating a virtual- and / or augmented- and / or mixed-reality device, for example since there is no need to determine a point of gaze of a subject. For example, a method may be performed without any user-related (e.g., subject-related) calibration. For example, a method may be performed without calibrating eye tracking for a subject. In some embodiments, a visual function test may be performed without determining a point of a gaze of a subject.

[0077] An optokinetic reflex may be exhibited in one or both eyes of a subject based on one or more graphics / and or widgets that are provided (e.g., rendered and displayed) to a subject. Common schemes for inducing optokinetic reflex, such as a grating moving over a background, may be adapted into methods of the present disclosure. For example, a series of spaced-apart shapes disposed over (e.g., overlaid on) or in (e.g., interspersed within) a background (e.g., a background graphic) may be used as a grating or like a grating in a test. An optokinetic reflex may be exhibited, induced, and / or ceased in response to the appearance of motion (e.g., relative motion) rendered and displayed to a subject, for example where the motion has a sufficient speed to induce or exhibit such reflex (or insufficient speed such that such reflex ceases). An optokinetic reflex may be exhibited, induced, and / or ceased in response to a contrast widget, for example disposed over (e.g., overlaid on) or in (e.g., interspersed within) a background graphic such that thereappears to be relative motion therebetween. An optokinetic reflex may be exhibited, induced, and / or ceased in response to an animated graphic, for example that includes spaced-apart shapes appearing to move with respect to (e.g., over) a background and / or with respect to (e.g., inside of) a frame (e.g., window). An optokinetic reflex may be exhibited, induced, and / or ceased in response to spaced-apart shapes (e.g., a series of spaced-apart shapes). An optokinetic reflex may be exhibited in response to an entirely virtual display (e.g., a VR scene) or a partially real-world display (e.g., an augmented reality or mixed reality scene).

[0078] In some methods, a background graphic is provided. A background graphic may be two-dimensional (e.g., appear as a plane) or three-dimensional (e.g., appear as a virtual and / or augmented scene), for example through which a subject can (effectively or actually) move). A background graphic may be provided by rendering and displaying a virtual graphic. A background graphic may be provided by displaying a live view of a field of view of a subject outside of a virtual- and / or augmented- and / or mixed-reality device, for example as is the case in certain augmented-reality embodiments. A background graphic may be a virtual rendering of a field of view of a subject outside of a virtual- and / or augmented- and / or mixed-reality device, for example as is the case in certain mixed-reality embodiments. A background graphic may be a scenic graphic, for example of a nature scene or urban scene, a background scene, or any other scene, realistic or abstract. A virtual and / or augmented scenic graphic may be used to give the appearance of a subject traveling by a vehicle (e g., a car, motorcycle, bicycle, airplane, or train). A background graphic may be displayed inside of a framing graphic, for example representing a window (e.g., of a vehicle) through which the background graphic and / or any contrast widget disposed over or in the background graphic appears to move. A framing graphic may appear as a foreground for a subject. A background graphic may be of a background color and / or a uniform background (e.g., uniform white). A background graphic may be animated (e.g., appear in motion to a subject) or not animated. For example, a background graphic may appear still to a subject. A background graphic may appear to be stationary behind a moving series of lines or rectangles (e.g., a moving grating), for example included in a contrast widget. A background graphic may be provided (e.g., displayed) within a virtual and / or augmented scene in a field of view (e.g., visual field) of a subject. A background graphic may be displayed in a field of view (e.g., visual field) of a subject.

[0079] A contrast widget may be provided (e.g., rendered and displayed) disposed over (e.g., overlaid on) or in (e.g., interspersed within) a background graphic, for example in a foreground, middle-ground, or background of the background graphic. A contrast widget may include a plurality of (e.g., a series of) spaced-apart shapes, for example lines or rectangles. Spaced-apart shapes may be uniformly spaced or irregularly spaced (e g., in an alternating spacing pattern). A contrast widget may appear as a grating to a subject. A contrast widget may be provided (e.g., rendered and displayed) such that it appears to be in motion relative to a background graphic, which can be accomplished, for example, by animating the contrast widget or the background graphic or both. Spaced-apart shapes of a contrast widget may be translucent (e.g., have an opacity in a range of 20% - 80%). Spaced-apart shapes of a contrast widget may be grayscale (e.g., dark) (e.g., black, e.g., and translucent). Spaced-apart shapes of a contrast widget may be rendered and displayed with an initial luminance of at least 5 cd / m2and no more than 30 cd / m2(e.g., before contrast changing). A contrast widget may be animated (e g., appear to be in motion to a subject) or not animated. For example, a contrast widget may appear to be still to a subject (e.g., while a background graphic appears to be in motion). A contrast widget may be displayed in a field of view (e.g., a visual field) of a subject.

[0080] A contrast widget may appear to be in fast, medium, or slow-motion relative to a background graphic. A contrast widget may appear to be moving horizontally or vertically relative to a background graphic. A contrast widget may appear to be moving unidirectionally relative to a background graphic (e g., in a horizontal or vertical direction). Appearance of motion (e.g., relative motion between a background graphic and a contrast widget) may occur over a period of time, for example of no more than 20 seconds, no more than 10 seconds or no more than 5 seconds.

[0081] In some methods, an animated graphic is provided. An animated graphic may be two-dimensional (e.g., appear as a flat plane) or three-dimensional (e.g., appear as a virtual and / or augmented scene, for example through which a subject can (effectively or actually) move). In some embodiments, an entire span of an animated graphic is animated. In some embodiments, only a portion (e.g., a central) portion. An animated graphic may be provided by rendering and displaying a virtual graphic. An animated graphic may be provided by, in part, displaying a live view of a field of view of a subject, for example as is the case in certain augmented-reality embodiments. An animated graphic may include a virtual rendering of a field of view of a subject, for example as is the case in certain mixed-reality embodiments. An animated graphic may be orinclude a scenic graphic, for example of a nature scene or urban scene, a background scene, or any other scene, realistic or abstract. An animated graphic may be used to give the appearance of a subject traveling by a vehicle (e.g., a car, motorcycle, bicycle, airplane, or train). An animated graphic may be displayed in a field of view (e.g., a visual field) of a subject. An animated graphic may be displayed in a virtual and / or augmented scene in a field of view (e.g., a visual field) of a subject.

[0082] An animated graphic may include spaced-apart shapes, for example a series of spaced-apart shapes. For example, an animated graphic may include a series of (e.g., vertical or horizontal) lines or rectangles. An animated graphic may include a grating, for example formed by a series of lines or rectangles. Spaced-apart shapes or a grating may appear to move (e.g., move together) in a particular direction in an animated graphic. For example, spaced-apart shapes may appear to move in a horizontal direction or a vertical direction. Spaced-apart shapes of an animated graphic may be translucent. Spaced-apart shapes of an animated graphic may have an opacity in a range of 20%-80%. Spaced-apart shapes of an animated graphic may be grayscale (e.g., dark) (e.g., black, e.g., and translucent). Spaced-apart shapes of an animated graphic may be rendered and displayed with an initial luminance of at least 5 cd / m2and no more than 30 cd / m2(e.g., before contrast changing). An animated graphic may include a series of spaced-apart shapes in a foreground, middle-ground, or background of a background. A background and / or spaced-apart shapes may be displayed inside of a frame, for example a window (e.g., of a vehicle) through which the background and / or spaced-apart shapes appear to move. A frame may appear as a foreground for a subject. Spaced-apart shapes may appear to move with respect to (e.g., over and / or inside of) a background and / or a frame (e.g., window) in an animated graphic. Such a background may be a stationary background. In some embodiments, an animated graphic includes a series of spaced-apart shapes that appear to move with respect to (e.g., over) a scenic graphic (e.g., that serves as the stationary background) and / or with respect to (e.g., inside of) a framing graphic (e.g., a window). Such a background may be a live view or virtual rendering of a field of view of the subject outside of an augmented- and / or mixed-reality device.

[0083] A change in contrast, such as an increase in contrast or reduction in contrast, may be made in a field of view of subject (e.g., in at least a portion of a field of view of the subject) during a method. Such a change in contrast may be made to, for example, test a contrast sensitivity of a subject, for example based on when the subject begins to exhibit or ceases to exhibit anoptokinetic reflex. A change in contrast may be progressive, for example continuously progressive or progressive in a series of discrete steps (e.g., one every 100 msec - 1 s). Such progressive contrast change may reduce testing time. Contrast may be progressively changed monotonically, for example only increasing or only decreasing, whether continuously or in discrete steps. Contrast may be progressively changed non-monotonically, for example alternating between increasing and decreasing changes. Each change in contrast may be by a constant amount or there may be a variable amount of contrast change for different changes. Contrast may be changed over a period of time, for example a period of time of no more than 20 seconds, no more than 10 seconds or no more than 5 seconds.

[0084] In some embodiments, a method includes changing (e.g., reducing or increasing) contrast in a field of view of a subject using a virtual- and / or augmented- and / or mixed-reality device (e.g., VR headset) (e.g., with eye tracking capability) such that one or both eyes of the subject begin to exhibit or cease to exhibit an optokinetic reflex. In some embodiments, a method includes inducing an optokinetic reflex in one or both eyes of a subject using a virtual- and / or augmented- and / or mixed-reality device (e.g., VR headset) (e.g., with eye tracking capability) (e.g., by displaying an animated graphic). A method may include changing (e.g., reducing or increasing) contrast in a field of view of a subject using a virtual- and / or augmented- and / or mixed- reality device (e.g., VR headset) (e.g., with eye tracking capability) while one or both eyes are exhibiting an optokinetic reflex. In some embodiments, a method includes changing (e.g., reducing or increasing) contrast in a field of view of a subject such that one or both eyes of the subject begin to exhibit or cease to exhibit an optokinetic reflex. In some embodiments, a method includes inducing an optokinetic reflex in one or both eyes of a subject (e.g., with an animated graphic). A method may include changing (e.g., reducing or increasing) contrast in a field of view of a subject while one or both eyes are exhibiting an optokinetic reflex. Contrast may be changed at least until a subject begins to have an optokinetic reflex. Contrast may be changed at least until a subject ceases to have an optokinetic reflex.

[0085] Changing contrast (e.g., progressively changing contrast) may be rendered and displayed to a subject. For example, changing contrast in a field of view of a subject may be rendered and displayed to the subject. As another example, changing contrast between a background graphic and a contrast widget may be rendered and displayed to a subject (e.g., by changing contrast of the contrast widget, the background graphic, or both). As another example,changing contrast in an animated graphic may be rendered and displayed to a subject (e.g., by changing contrast of spaced-apart shapes, a background, or both, provided therein).

[0086] A contrast widget may be provided (e.g., rendered and displayed) to a subject with changing contrast (e.g., progressively changing contrast). A background graphic may be provided (e.g., rendered and displayed) to a subject with changing contrast (e.g., progressively changing contrast). An animated graphic may be provided (e.g., rendered and displayed) to a subject with changing contrast (e.g., progressively changing contrast). Spaced-apart shapes may be provided (e.g., rendered and displayed) to a subject with changing contrast (e.g., progressively changing contrast). A background may be provided (e.g., rendered and displayed) with changing contrast (e.g., progressively changing contrast). Contrast of at least a portion of a field of view of a subject may be changed (e.g., progressively changed). A contrast widget and a background graphic may be provided (e.g., rendered and displayed) to a subject with changing contrast (e.g., progressively changing contrast). Spaced-apart shapes and a background may be provided (e.g., rendered and displayed) to a subject with changing contrast (e.g., progressively changing contrast).

[0087] Contrast may be changed at least until a background and spaced-apart shapes are indistinguishable to a subject. Contrast may be changed at least until a background and spaced- apart shapes are distinguishable to a subject. Contrast may be changed at least until a background graphic and a contrast widget are indistinguishable to a subject. Contrast may be changed at least until a background graphic and a contrast widget are distinguishable to a subject.

[0088] Contrast may be changed by changing a size of spaced-apart shapes, for example ones included in a contrast widget. Changing size may include reducing or expanding at least one dimension (e.g., width) of the spaced-apart shapes, for example until the spaced-apart shapes disappear or become contiguous, respectively.

[0089] Contrast may be changed by changing an opacity of spaced-apart shapes included in a contrast widget and / or of a background graphic. For example, an opacity of spaced-apart shapes may be reduced (e.g., until the shapes become transparent) or increased. Contrast may be changed by changing an opacity of spaced-apart shapes and / or a background.

[0090] Contrast may be changed by graying or de-graying, for example until an entire field of view of the subject becomes gray (e.g., uniformly gray). For example, a field of view of a subject may be uniformly grayed or de-grayed during changing of contrast. In some embodiments, a background graphic and a contrast widget are simultaneously (e.g., progressively) grayed or de-grayed. In some embodiments, a background and spaced-apart shapes are simultaneously (e.g., progressively) grayed or de-grayed. In some embodiments, an animated graphic is progressively grayed or de-grayed to change contrast. Contrast may be changed by (e.g., progressively) (e.g., uniformly) graying or de-graying at least a portion of a field of view of a subject [e.g., until an entire field of view of the subject becomes gray (e.g., uniformly gray)].

[0091] Contrast may be changed by changing relative grayscale values between spaced- apart shapes and area between the spaced-apart shapes. For example, spaced-apart shapes may have a grayscale value of 0 and area therebetween may have a grayscale value of 255 at high contrast and there may be a lower difference in grayscale values at low contrast (e.g., shapes at 100 and area therebetween at 155 or shapes at 127 and area therebetween at 128). Contrast may be changed (e.g., reduced or increased) between such a high contrast and such a low contrast. In some embodiments, rendering and displaying a contrast widget may include rendering and displaying area between spaced-apart shapes at a particular (e.g., changing) grayscale value. In some embodiments, rendering and displaying an animated graphic may include rendering and displaying area between spaced-apart shapes at a particular (e.g., changing) grayscale value.

[0092] Contrast may be changed by changing at least one color, for example to have it correspond or no longer correspond to another color. For example, at least color of a contrast widget may be changed to correspond or no longer correspond to one or more colors of a background graphic. As another example, at least color of spaced-apart shaped may be changed to correspond or no longer correspond to one or more colors of a background. Contrast may be changed by lightening and / or darkening one or more portions of a field of view of a subject (e.g., a contrast widget, a background graphic, an animated graphic, a background, and / or spaced-apart shapes), for example to change (e.g., reduce or increase) the contrast therebetween.

[0093] In some embodiments, a combination of the foregoing mechanisms is applied to change contrast.

[0094] Spatial frequency of spaced-apart shapes may be progressively changed during a method. Such progressive spatial frequency change may reduce testing time. Spatial frequency of a contrast widget (e.g., of spaced-apart shapes thereof) may be progressively changed during a method. Spatial frequency may be progressively changed continuously or may be progressively changed in discrete steps. Spatial frequency may be progressively changed monotonically, for example only increasing or only decreasing, whether continuously or in discrete steps. Spatialfrequency may be progressively changed non-monotonically, for example alternating between increasing and decreasing changes. Each change in spatial frequency may be by a constant amount or there may be a variable amount of spatial frequency change for different changes. Spatial frequency may be changed over a period of time, for example a period of time of no more than 20 seconds, no more than 10 seconds or no more than 5 seconds. Spatial frequency may be changed, for example, by changing size [e.g., thickness (e.g., width)] of spaced-apart shapes, changing distance between (e.g., spacing of) spaced-apart shapes, and / or changing relative speed of spaced- apart shapes.

[0095] In some embodiments, a background graphic is provided (e.g., rendered and displayed) and a contrast widget is rendered and displayed such that the contrast widget appears to be in motion while progressively changing both contrast of the contrast widget (e.g., spaced- apart shapes thereof) relative to the background graphic and spatial frequency of spaced-apart shapes of the contrast widget. In some embodiments, an animated graphic is rendered and displayed such that spaced-apart shapes of the animated graphic appear to be in motion while progressively changing both contrast of the animated graphic and spatial frequency of the spaced- apart shapes. In some embodiments, a background graphic is provided (e.g., rendered and displayed) and a contrast widget is rendered and displayed such that spaced-apart shapes of the contrast widget appear to be in motion at a plurality of combinations of contrast and spatial frequency of the spaced-apart shapes. In some embodiments, an animated graphic is rendered and displayed such that spaced-apart shapes of the animated graphic appear to be in motion at a plurality of combinations of contrast and spatial frequency of the spaced-apart shapes. In some embodiments, spaced-apart shapes are rendered and displayed so as to appear to be in motion at a plurality of combinations of contrast and spatial frequency of the spaced-apart shapes. In some embodiments, it is preferrable to progressively change spatial frequency continuously and progressively change contrast discretely. Such a combination may be easier to test, for example easier to track a subject’s optokinetic reflex in response to changes.

[0096] Spatial frequency may be (effectively) changed through relative speed of spaced- apart shapes. For example, in some embodiments where an animated graphic or background graphic appears, at least in part, as a natural environment (e.g., nature scene or urban scene), an apparent speed at which a subject is traveling through the environment may be changed thereby changing (e.g., increasing or decreasing) a relative speed of spaced-apart shapes. For example, asubject may observe a virtual- and / or augmented- and / or mixed reality scene in which the subject appears to be by a vehicle (e.g., car, bicycle, motorcycle, airplane, or train) and changing (e.g., increasing or decreasing) an apparent speed of the vehicle may result in a change in relative speed of spaced-apart shapes (e.g., appearing to be located outside of a window of the vehicle).

[0097] Different combinations of spatial frequency and contrast may be used (e.g., rendered and displayed to a subject) in a method. For example, different combinations of spatial frequency of spaced-apart shapes in a contrast widget and contrast between a background graphic and a contrast widget may be used. For example, different combination of spatial frequency of spaced-apart shapes of an animated graphic and contrast of the spaced-apart shapes in the animated graphic may be used. Movement of one or both eyes of a subject may be tracked over different combinations of spatial frequency and contrast, for example to detect and / or quantify optokinetic reflex in response to one or more of the combinations. For example, eye movement may be tracked in order to determine at which combinations of spatial frequency and contrast optokinetic reflex ceases to occur and / or begins to occur. Contrast and / or spatial frequency at which a subject begins to have or ceases to have an optokinetic reflex may be determined and / or recorded. In some embodiments, for each of a plurality of combinations of contrast and spatial frequency at which a subject begins to have or ceases to have an optokinetic reflex in response to appearance of motion. A contrast sensitivity function for a subject may be determined and / or recorded, for example based on tracking movement of one or both eyes of a subject at different combinations of spatial frequency and contrast. Such a contrast sensitivity function may be compared to a baseline (e.g., of a person with normal visual acuity) to determine whether a subject has visual deficit and / or lower visual acuity.

[0098] Eye movement of one or both eyes of a subject may be tracked (e.g., automatically) during a method. Eye movement may be tracked to monitor an optokinetic reflex of a subject in one or both eyes. Eye movement may be tracked to determine onset or cessation of an optokinetic reflex in one or both eyes of a subject and / or for how long a subject exhibits an optokinetic reflex in one or both eyes. Eye movement may be tracked, for example using eye tracking capability of a virtual- and / or augmented- and / or mixed-reality device, while a subject is exhibiting an optokinetic reflex in one or both eyes. Eye movement may be tracked, for example using eye tracking capability of a virtual- and / or augmented- and / or mixed-reality device, while contrast is being changed. Eye movement may be tracked, for example using eye tracking capability of avirtual- and / or augmented- and / or mixed-reality device, in response to a graphic and / or a widget [e g., in response to a contrast widget disposed over (e.g., overlaid on) or in (e.g., interspersed within) a background graphic]. Tracking one or both eyes of a subject may occur automatically. Tracking one or both eyes may be performed using a virtual- and / or augmented- and / or mixed- reality device having eye tracking capability (e.g., including one or more cameras for eye tracking, and optionally an illumination source). Tracking one or both eyes may be performed using a device (e.g., camera) separate from a device on which graphics and / or widgets are displayed (e.g., a display monitor, such as an LCD monitor). Tracking may include capturing images of one or both eyes of a subject, for example as still images or frames of a video image. Track movement of one or both eyes of a subject may include capturing still images periodically (e.g., where the period is in a range of from 0.01 s to 1 s). A method may include determining an abnormality (e.g., an abnormal optokinetic reflex) or condition (e.g., retinal condition) of a subject based at least in part on tracking movement of one or both eyes of the subject. An abnormal optokinetic reflex may be indicative of a motor disorder.

[0099] A method may include tracking (e.g., automatically) movement of one or both eyes of a subject to detect and / or quantify an optokinetic reflex of a subject. For example, a method may include tracking (e.g., automatically) movement of one or both eyes of a subject to detect and / or quantify an optokinetic reflex of a subject during display of an animated graphic. As another example, a method may include tracking (e.g., automatically) movement of one or both eyes of a subject to detect and / or quantify an optokinetic reflex of a subject during display of a contrast widget disposed over (e.g., overlaid on) or in (e.g., interspersed within) a background graphic. A method may include (e.g., automatically) tracking movement of one or both eyes of a subject in response to a contrast widget disposed over (e.g., overlaid on) or in (e.g., interspersed within) a background graphic (e.g., in response to the appearance of relative motion therebetween). Tracking movement of one or both eyes of a subject may include detecting and / or quantifying inducement or cessation of an optokinetic reflex of a subject. A method may include tracking (e.g., detecting and / or quantifying) an optokinetic reflex of a subject, for example caused and / or induced by an animated graphic, motion of spaced-apart shapes, and / or the appearance of relative motion between a contrast widget and a background graphic.

[0100] Tracking movement of one or both eyes of a subj ect may include determining when an optokinetic reflex begins or ceases due to a change in contrast, for example in a field of viewof a subject, between a contrast widget and a background graphic, or in an animated graphic. Tracking movement of one or both eyes of a subject may include determining when an optokinetic reflex of a subject begins and / or ceases, for example in response to a reduction or increase in contrast. In some embodiments, a method includes automatically determining when contrast (e.g., in an animated graphic or between a contrast widget and a background graphic) is low enough for an optokinetic reflex of a subject to cease. A method may include determining an abnormality (e.g., an abnormal optokinetic reflex) or condition (e.g., retinal condition) of a subject based at least in part on tracking an optokinetic reflex in one or both eyes of the subject.

[0101] One or more characteristics may be determined and / or recorded as part of a method, for example when it is determined that a subject begins to have or ceases to have an optokinetic reflex. One or more characteristics may be determined and / or recorded as part of a method based at least in part on tracking of movement of one or both eyes of a subject. In some embodiments, a contrast at which an optokinetic reflex begins or ceases in one or both eyes of a subject is determined and / or recorded. The contrast may be or include, for example, (i) a relative contrast, for example between a background graphic and a contrast widget or between spaced-apart shapes and a background, (ii) a contrast level (e.g., opacity), for example of spaced-apart shapes, or (iii) a gray value of a field of view of a subject. A frequency (e.g., periodicity) of spaced-apart shapes when an optokinetic reflex begins or ceases in one or both eyes of a subject may be determined and / or recorded. A period of time that it took for a subject to begin having or cease having an optokinetic reflex, for example to an animated graphic or a contrast widget disposed over (e.g., overlaid on) or in (e.g., interspersed within) a background graphic, may be determined and / or recorded. When a subject began having or ceased having an optokinetic reflex, for example to an animated graphic or a contrast widget disposed over (e.g., overlaid on) or in (e.g., interspersed within) a background graphic, may be determined and / or recorded.

[0102] A contrast and / or spatial frequency may be recorded in a two-dimensional contrast sensitivity space. For example, a contrast sensitivity space where contrast (e.g., contrast sensitivity) represents one dimension and spatial frequency represents the other dimension may be used. Well-defined contrast sensitivity functions in such two-dimensional measurement spaces have been studied and developed in the art. Recording contrast and / or spatial frequency in such a two-dimensional measurement space may allow performance of a subject to be compared to a baseline contrast sensitivity function (e.g., taken from the literature or independently developed)(e.g., for a subject with normal visual acuity), for example in order to understand and / or assess visual function (e.g., contrast sensitivity) of a subject. A contrast sensitivity at one or more spatial frequencies that falls below a baseline contrast sensitivity function may indicate visual deficit and / or lower visual acuity for a subject. Spatial frequency may be determined and / or recorded in units of cycles per degree. Contrast may be determined and / or recorded as a dimensionless number. For example, contrast threshold is often defined as the minimum contrast that a subject can resolve, and contrast sensitivity defined as the reciprocal of contrast threshold.

[0103] In some embodiments, an optokinetic nystagmus profile may be determined, for example, based at least in part on tracking movement of one or both eyes of a subject. An optokinetic nystagmus profile may include one or more characteristics of an optokinetic reflex in one or both eyes of a subject as a function of time. For example, an optokinetic nystagmus profile may include whether an optokinetic reflex is occurring or not in one or both eyes of a subject. An optokinetic nystagmus profile may include an amount of movement in one or both eyes of a subject during an optokinetic reflex. An optokinetic nystagmus profile may include a direction of movement in one or both eyes of a subject during an optokinetic reflex. An optokinetic nystagmus profile may include a phase and / or frequency of eye movement in one or both eyes of a subject.

[0104] An optokinetic nystagmus profile may be compared to one or more graphics and / or one or more widgets displayed to a subject. For example, an optokinetic nystagmus profile may be compared to an animated graphic. As another example, an optokinetic nystagmus profile may be compared to a contrast widget disposed over (e.g., overlaid on) or in (e.g., interspersed within) a background graphic. Such comparisons may include determining an alignment (or lack thereof) between an optokinetic reflex exhibited in one or both eyes of a subject and what was visually provided (e.g., displayed) to the subject. For example, such comparison may include a determination that an optokinetic reflex corresponds to or does not correspond to a stimulus provided to a subject that was intended to induce an optokinetic reflex [e.g., corresponds or does not correspond in terms of timing, direction, and / or extent (e.g., amount of movement)]. Such a comparison may be used to determine whether a subject has an abnormality (e.g., an abnormal optokinetic reflex) or condition (e.g., retinal condition). Such comparisons may be used to determine, for example, (i) for at least one point in time, whether a subject can see a contrast widget and / or a graphic, (ii) when an optokinetic reflex in one or both eyes of a subject begins and / or ceases, (iii) a contrast level at which an optokinetic reflex in one or both eyes of a subject beginsand / or ceases, or (iv) a combination thereof. A contrast level determined by such a comparison may be, for example, a relative contrast level between the background graphic and the contrast widget, a contrast level (e.g., opacity) of the contrast widget, or a gray level of at least a portion of a field of view of the subject.

[0105] Methods disclosed herein may be a photostress recovery test or be for performing a photostress recovery test. In some embodiments, a bleaching graphic is first displayed to a subject before an animated graphic is rendered and displayed to the subject while movement of one or both eyes of the subject are tracked (e.g., in order to detect and / or quantify optokinetic reflex). In some embodiments, a bleaching graphic is first displayed to a subject before a background graphic with contrast widget are provided and / or rendered and displayed to the subject while movement of one or both eyes of the subject are tracked (e.g., in order to detect and / or quantify optokinetic reflex). Time it takes a subject to exhibit or cease to exhibit an optokinetic reflex after a bleaching graphic may be determined and / or recorded in order to characterize (e.g., quantify) photostress recovery for the subject.

[0106] A bleaching graphic may expose one or both eyes of a subject to light (e.g., light of a certain luminance above background). A bleaching graphic may be displayed for a period of time. For example, a bleaching graphic may be displayed for at least 1 second, at least 2 seconds, at least 3 seconds, at least 4 seconds, at least 5 seconds, and, optionally, no more than 10 seconds. In general, a period of time for which a bleaching graphic is displayed is intended to give time for a subject to adjust to a bright environment (e.g., and correspondingly exhibit characteristic pupil diameter shrinking). In some embodiments, a period of time that a bleaching graphic is displayed may be determined based on tracking pupil diameter for a subject, for example a bleaching graphic may be displayed for a period of time it takes for the subject’s pupil diameter to shrink to no more than a threshold diameter (e.g., of 3.5 mm, 3 mm, or 2.5 mm). Optionally, a bleaching graphic may be further displayed for a short period after a pupil diameter threshold has been crossed, for example for at least an additional 1 second, 2 seconds, or 3 seconds. A period of time that a bleaching graphic is displayed may only begin once it is determined that a subject’s eye or eyes are opened. A camera used for eye tracking (e.g., in a VR headset or other virtual- and / or augmented- and / or mixed-reality device) may track whether a subject’s eye or eyes are open. In general, it will be common for a subject’s eye or eyes to close, at least momentarily, upon initial display of a bleaching graphic given its sharp contrast in brightness, for example from a precedingdark screen. In some embodiments, a period of time for which a bleaching graphic is displayed is extended based on a subject’s eye or eyes having been closed (e.g., how long a subject’s eye or eyes were closed), thereby accounting for the closure. A method may include determining, by a processor, whether one or more eyes of a subject are open. In some embodiments, a bleaching graphic has sufficient luminance to induce a photostress to a subject. In some embodiments, a bleaching graphic is rendered and displayed with a luminance of at least 50 candela per square meter (cd / m2) (e.g., at least 55 cd / m2, at least 60 cd / m2, at least 65 cd / m2, at least 70 cd / m2, at least 75 cd / m2, at least 80 cd / m2, at least 85 cd / m2, at least 90 cd / m2, at least 95 cd / m2, at least 100 cd / m2, at least 105 cd / m2, at least 110 cd / m2, at least 115 cd / m2, or at least 120 cd / m2) and, optionally, no more than 120 cd / m2. In some embodiments, a bleaching graphic is rendered and displayed with a luminance of at least 60 cd / m2and no more than 120 cd / m2.

[0107] Systems for conducting a visual function test on a subject (e.g., an optokinetic reflex assessment) are also provided herein. A system may include a virtual- and / or augmented- and / or mixed-reality device (e.g., VR headset with eye tracking capability), for example for providing (e.g., rendering and displaying) one or more graphics and / or one or more widgets to a subject and / or tracking one or both eyes of a subject as part of a method. A system may display one or more graphics and / or one or more widgets on a head-mounted (e.g., face-mounted) display of a virtual- and / or augmented- and / or mixed-reality device. A system may include a virtual- and / or augmented- and / or mixed-reality device (e.g., VR headset with eye tracking capability) operable to perform at least part of a method disclosed herein and / or operable to be used in performance of at least part of a method disclosed herein. A system may include a virtual- and / or augmented- and / or mixed-reality device (e.g., VR headset with eye tracking capability) for conducting a visual function test (e.g., an optokinetic reflex assessment) on a subject. A system may be a virtual- and / or augmented- and / or mixed-reality device system. A system may include a processor of a computing device and a memory having instructions stored thereon, wherein the instructions, when executed by the processor, cause the processor to perform a method disclosed herein.

[0108] A virtual- and / or augmented- and / or mixed-reality device (e.g., for performing a visual function test) may be a consumer device (e.g., a consumer VR headset). A virtual- and / or augmented- and / or mixed-reality device (e.g., for performing a visual function test) may be a consumer grade device (e.g., a consumer grade VR headset). A virtual- and / or augmented- and / ormixed-reality device (e.g., for performing a visual function test) may be a professional device (e.g., a professional VR headset). A virtual- and / or augmented- and / or mixed-reality device (e.g., for performing a visual function test) may be a professional grade device (e.g., a professional grade VR headset). A virtual- and / or augmented- and / or mixed-reality device may include an eyetracking camera. Such an eye-tracking camera may be included in a headset, or elsewhere. A virtual- and / or augmented- and / or mixed-reality device may include an illumination source (e.g., for illuminating one or both eyes for tracking purposes). A virtual- and / or augmented- and / or mixed-reality device may have eye-tracking capability. Eye tracking, such as with a virtual- and / or augmented- and / or mixed-reality device, may utilize eye tracking software and / or hardware (e.g., utilize an eye tracking camera, e.g., with associated software and / or illumination source).

[0109] Figs. 1 A-l J illustrate views from a visual function test based on optokinetic reflex performed using a VR headset with eye tracking capability, according to some embodiments of the present disclosure. In this example of a test, a subject is shown a virtual reality scene in which the subject appears to be riding a train. Such scenes allow for the motion (e.g., relative motion) that the subject will view to seem more natural and, overall, for the test to seem more pleasant to the subject and less clinical. Other vehicles may also be used, such as a car, a bicycle, a motorcycle, or an airplane. Especially for subjects who may be apprehensive about using a VR headset, using a simulation of a (mostly) real world experience for a test may ease apprehension about taking the test. Likewise, occupying a full field of view of a subject during a test may be preferable for comfort of the subject. Moreover, looking out of a window of a moving vehicle is known to induce or aid in inducing an optokinetic reflex and therefore may assist in testing.

[0110] Figs. 1A- IB illustrate initial views that a subject may experience during a test. In Fig. 1A, a subject initially appears to be in a train car on a moving train. The subject can look around the train, including looking outside of a window next to a seat in which the subject is seated, as shown in Fig. IB. A nature scene outside the window can be observed by the subject; the nature scene will appear to move because the train is in motion. The subject may be directed (e.g., by a test operator and / or audio cue) to look out of the window a short period after the test initializes after which the operative part of the test begins. Similarly, in some embodiments, an augmented- and / or mixed-reality view may be presented to a subject where the background graphic 100 is, for example, a live view or virtual rendering of the subject’s surroundings outside of an augmented- and / or mixed-reality device (instead of a virtual nature scene) over (e.g., overlaid on) or in (e.g.,interspersed within) which a contrast widget 50 is disposed. For example, the rectangles of the contrast widget shown in Figs. 1A-1J may be overlaid over the live view or virtual rendering in order to track an optokinetic reflex in one or both eyes of a subject.

[0111] Figs. 1 C-l J illustrate the addition of spaced-apart shapes (e.g., of a contrast widget) 50 disposed over (e.g., overlaid on) or in (e.g., interspersed within) a background 100 of the moving train scene. The subject will observe this animated graphic during the test. The contrast widget 50 appears as translucent (e.g., about 50% opacity) spaced-apart shapes (in this case rectangles), effectively forming a grating. Here, for purposes of apparent realism, the contrast widget 50 includes not only spaced-apart shapes but also small shadows for the spaced-apart shapes. The nature of the spaced-apart rectangles 50, for example their contrast, size, shape, spacing, and relative orientation (e.g., position) to the background 100, causes the spaced-apart shapes 50 to appear to be in motion. In some embodiments, the motion is relative to the nature scene 100 behind the shapes 50 (e.g., the mountains and background bushes). The motion can induce an optokinetic reflex in the subject, even if the subject has trouble seeing individual features in this animated graphic (e.g., even if the subject has poor visual acuity). The portion of the test illustrated by Figs. 1C-1G, Figs. 1G-1J, or Figs. 1C-1J may take place over a period of, for example, no more than 20 seconds (e.g., 10 seconds).

[0112] In Figs. 1C-1G, as the appearance of motion proceeds, contrast between the background 100 and the contrast widget 50 that includes the spaced-apart shapes progressively reduces. In this case, the progressive reduction in contrast is caused by a uniform graying of a field of view of the subject, specifically the subject’s view out of the window. For purposes of apparent realism, any portion of the interior of the train that is in the subject’s field of view is not grayed. Thus, the progressive graying appears as if the window through the subject views the animated graphic were changing opacity (e.g., as if the window were made of smart glass transitioning to an opaque privacy mode). The speed of the vehicle (e.g., train) in which the subject appears to be may be progressively changed during this phase of the test (e.g., sped up or slowed down) in order to change the apparent spatial frequency of the spaced-apart shapes and therefore make different measurements of contrast sensitivity. In general, there will be a speed (spatial frequency) at which a subject can no longer distinguish adjacent shapes and an optokinetic reflex will cease or at which a subject begins to distinguish adjacent shapes and an optokinetic reflex will begin. Other progressive reductions in contrast may be used additionally or alternatively to thegraying illustrated in Figs. 1C-1G, for example the spaced-apart shapes could change size (e.g., vertically and / or horizontally) and / or opacity (e.g., becoming more transparent, optionally until totally transparent).

[0113] Figs. 1G-1J illustrate the inverse of Figs. 1C-1G, that is, progressively increasing contrast. The progressive change, whether increase or reduction, may be made continuously (e.g., frame by frame) or in a series of discrete steps (e.g., made every period of time, such as a period having a length in a range of 100 msec - 1 s). The progressive reduction and then increase in contrast illustrated in Figs. 1C-1J may be repeated one or more times, for example, to provide multiple measurements related to onset and / or cessation of an optokinetic reflex. The speed of the vehicle (e.g., train) in which the subject appears to be may be progressively changed during this phase of the test (e.g., sped up or slowed down) in order to change the apparent spatial frequency of the spaced-apart shapes and therefore make different measurements of contrast sensitivity. In general, there will be a speed (spatial frequency) at which a subject can no longer distinguish adjacent shapes and an optokinetic reflex will cease or at which a subject begins to distinguish adjacent shapes and an optokinetic reflex will begin.

[0114] While Figs. 1C-1G illustrate a contrast widget with sufficient contrast to induce an optokinetic reflex once, or shortly after, the contrast widget is first displayed to the subject, other tests may start with an animated graphic that has sufficiently reduced contrast that there is initially no responsive optokinetic reflex and the optokinetic reflex onsets as contrast is progressively increased. For example, similarly to what is illustrated Figs. 1G-1J, the train window may initially appear as grayed and progressively appear to become transparent (e.g., as if the window were made of smart glass transitioning to a transparent mode).

[0115] During the progressive change (e.g., reduction or increase) in contrast, eye movement of the subject may be tracked, for example in order to observe onset of and / or cessation of an optokinetic reflex to the apparent motion of the spaced-apart shapes of the contrast widget (e.g., relative to the background graphic) in the animated graphic. Moreover, an optokinetic nystagmus profile may be determined that shows how the subject’s eye movement changes as a function of time during the progressive change. That nystagmus profile may be compared to the motion of the spaced-apart shapes. For example to determine (i) for at least one point in time, whether the subject can see the contrast widget, (ii) when an optokinetic reflex in the one or both eyes of the subject begins and / or ceases, (iii) a contrast level at which an optokinetic reflex in oneor both eyes of a subject begins and / or ceases, or (iv) a combination thereof, based at least in part on a result of the comparing, for example based on a contrast level between the background graphic and the contrast widget determined by the comparison. A contrast level may be a relative contrast level between the background graphic and the contrast widget, a contrast level (e.g., opacity) of the contrast widget, or a gray level of at least a portion of a field of view of the subject, for example.

[0116] Fig. IK illustrates a view of output from an eye tracking camera of the VR headset used for the test illustrated in Figs. 1 A-l J and just described. A feed of the output may be recorded (e.g., for documentation purposes) and / or displayed live to a test operator, for example for administration and / or monitoring purposes. In some embodiments, once, or shortly after, a contrast widget having sufficient relative contrast is displayed to a subject, the subject will have an optokinetic reflex in one or both eyes. Such a reflex may be observed with an eye tracking camera. In Fig. IK, both eyes are being tested and therefore both eyes could have an optokinetic reflex, observable as a repeated horizontal shifting (e.g., back and forth movement). In some embodiments, vertical motion is used and therefore movement of one or both eyes of a subject may be vertical rather than horizontal. In some embodiments, the exact movement (e.g., distance and / or frequency) is not of primary interest but rather simply whether (and when) any optokinetic reflex is happening (e.g., as determined using an optokinetic nystagmus profile). In some embodiments, an abnormality in optokinetic reflex is determined based on movement of one or both eyes of a subject (e.g., based on distance and / or frequency of movement).

[0117] Fig. IL illustrates an example of a baseline contrast sensitivity function plotted in contrast-spatial frequency space. Measurements made during the test illustrated in Figs. 1A-1J may be plotted and compared to the baseline contrast sensitivity function. As just described, in this exemplary test, spatial frequency can be varied by changing the train’s speed as it appears to the subject, for example while maintaining constant thickness / width and height of the spaced-apart shapes. Contrast can be changed by graying at least a portion of a field of view of the subject and / or opacity of the spaced-apart shapes. In some embodiments, a finite number of discrete contrasts (e.g., opacities and / or grayings) and a continuous acceleration and / or deceleration of the vehicle (e.g., train) are used to test different points in the contrast-spatial frequency space and compare to the baseline function in Fig. IL. Contrast sensitivity (e.g., for a particular spatial frequency) can be determined based on contrast at which an optokinetic reflex begins or ceases tooccur. Therefore, subject-specific spatial frequency thresholds for specific contrast values in a contrast sensitivity function for the subject can be determined.

[0118] Figs. 2A-2B illustrate different manners of apparent motion (e.g., relative to a background) that may be used. The example test illustrated by Figs. 1A-1J uses a horizontal motion with a complex background, for subject comfort. Fig. 2A illustrates a horizontal motion of spaced-apart shapes, though with a simple white background and black rectangular shapes having 50% opacity that span a field of view of a subject. In some embodiments, contrast may be reduced by changing relative grayscale values between the spaced-apart shapes and area between the spaced-apart shapes [e.g., where spaced-apart shapes have a grayscale value of 0 and area therebetween has a grayscale value of 255 at high contrast and a difference in grayscale values is reduced at low contrast (e.g., shapes at 100 and area therebetween at 155)]. The spaced-apart shapes form a grating over the background. The left panel shows a first point in time and the right panel shows motion that has occurred by a second point in time after the first. Fig. 2B illustrates a test with similar parameters to Fig. 2A though with a vertical motion instead of a horizontal motion. (In general, horizontal motion will induce a horizontal optokinetic reflex while vertical motion will induce a vertical optokinetic reflex.) Progressive change in contrast may be accomplished in both cases by, for example, changing opacity (e.g., increasing or decreasing from 50%) and / or changing horizontal and / or vertical size of the shapes. Animated graphics such as those in Figs. 2A-2B could be rendered and displayed to a subject using a virtual- and / or augmented- and / or mixed-reality device. In some embodiments, the background may be a live view or virtual rendering of a field of view of the subject outside of an augmented- and / or mixed- reality device instead of simply white as shown in Figs. 2A-2B. Figs. 3A-3B illustrates different exemplary mechanisms for progressively changing contrast in the exemplary spaced-apart shapes and background of Fig. 2A: changing (reducing) vertical size (Fig. 3A), changing (reducing) horizontal size (Fig. 3B), and changing (reducing) opacity (Fig. 3C). Fig. 3B can also be taken to illustrate (progressively) changing spatial frequency of spaced-apart shapes and a separate manner of progressively changing contrast may be used (e.g., the manner illustrated in Fig. 3C and / or changing grayscale value and / or graying at least a portion of a field of view).

[0119] Virtual- and / or augmented- and / or mixed-reality devices (e.g., VR headsets) may be used in various embodiments described herein. Commercially-available virtual reality (VR), augmented reality (AR), and / or mixed reality (MR) systems feature head-worn and / or face-wornhardware, as well as eye-tracking software, and may be used as components of the systems and methods described herein. As used herein, the terms “headset” or “VR headset” refer broadly to such head- or face-worn systems that implement virtual reality, augmented reality, and / or mixed reality functionality. A virtual- and / or augmented- and / or mixed-reality device (e.g., VR headset) may include eye tracking capability. Eye tracking capability may be used to track movement of one or both eyes of a subject, for example to determine whether and / or when a subject is having an optokinetic reflex (optokinetic nystagmus) (e.g., when such reflex begins and / or ends). Eye tracking capability may be used to determine an optokinetic nystagmus profile. A virtual- and / or augmented- and / or mixed-reality device (e.g., VR headset) may be a consumer grade device. A virtual- and / or augmented- and / or mixed-reality device (e.g., VR headset) may be a professional grade device.

[0120] An example of a professional -grade VR headset system with eye tracking capability that can be used with the systems and methods described herein is the VIVE Pro Eye Office VR system, manufactured by HTC Corporation (headquartered in Xindian, New Taipei, Taiwan), as described at https: / / business.vive.com / us / product / vive-pro-eye-office / and in U.S. Patent No. 10,990,170, entitled, “Eye tracking method, electronic device, and non-transitoiy computer readable storage medium,” and in U.S. Patent No. 10,705,604, entitled, “Eye tracking apparatus and light source control method thereof,” the disclosure of each of which is incorporated herein by reference. Another example of a virtual- and / or augmented- and / or mixed-reality device that includes eye tracking capability and may be used with the systems and methods described herein is the Varjo Aero manufactured by Varjo Technologies Oy (Helsinki, FI). A Vaijo Aero may be used to track eye movement of a subject (e.g., to track an optokinetic reflex) while rendering and displaying one or more screens, graphics, and / or widgets to the subject.

[0121] Fig. 4A shows an illustrative system 400 that can perform methods described herein. The illustrative system 400 includes a memory 402 on which instructions are stored that, when executed by processor 404, perform one or more methods described herein. Optionally, the system 400 can include a VR headset 410, for example from which a first and second data stream corresponding to a gaze direction and gaze origin are sent to, and received by, the processor 404 for use in executing instructions stored on the memory 402.

[0122] Fig. 4B shows a detailed block diagram of components that may be included in the VR headset 410, for example if the VR headset 410 is a VIVE Pro Eye Office VR system. Thecomponents may include one or more of (i) a camera 412 for tracking an eye of a subject; (ii) one or more illumination sources LSI, LS2, . .. LSN for illuminating an eye of the subject to provide signal to the camera 412 in order to track the eye; (iii) one or more optics 416, such as lenses, reflectors, or other light guiding components, for guiding light that has interacted with the eye (e.g., reflected from the eye) to the camera 412; (iv) a display 420 for displaying images to the subject; (v) one or more headset processors 414 for processing data from camera 412, for the display 420, or from and / or for other components in the VR headset 410; and (vi) one or more adjustment and / or head support mechanisms 422 for physically adjusting (e.g., orienting and / or aligning) the VR headset on a subject (e.g., relative to an eye of the subject and / or for comfort during use). Generally, the VR headset 410 is a wearable apparatus that may be worn over one or both eyes of a subject at a time. For example, the VIVE Pro Eye Office VR system is worn over both eyes but other VR headsets that can be used may have a “monocle” style that is worn over one eye at a time. The display 420 may also be used to provide one or more graphics and / or widgets (e.g., simulated images) to the subject.

[0123] The processor 404 that executes instructions may be one of the headset processors 414. The memory 402 and the processor 404 may be housed in the VR headset 410 or may be separately housed, for example in a server or other computing device that is in communication (e.g., wireless communication) with the VR headset 410. The one or more headset processors 414 may be used to send data stream(s) to the processor 402, for example wirelessly.

[0124] The VR headset 410 may also include one or more adjustment and / or head support mechanisms 422. Adjustment mechanisms 422 may include one or more mechanical mechanisms, such as knobs, straps, dials, or the like. The adjustment mechanisms 422 may be used to adjust the horizontal and / or vertical position of the headset (e.g., a component thereof, such as the display 420) relative to the head of a subject. For example, the VIVE Pro Eye Office VR system includes mechanism(s) to adjust the interpupillary distance (IPD) to the particular subject using the system by an “IPD knob.” IPD adjustment may involve first determining a physical IPD measurement, for example manually by the subject or with assistance from a physician, optometrist, or other healthcare provider. As another example, the VIVE Pro Eye Office VR system includes a lens distance adjustment button that can be pressed to allow a subject to adjust the distance of the lens further or closer to his or her face. Such an adjustment may be used to account for subj ect anatomy or other factors, such as glasses or other sight aids. A user may be prompted to make adjustmentof one or more of the adjustment mechanism(s) 422 based on methods disclosed herein that use eye tracking (e.g., in combination with a virtual iron sight (alignment aid)) to determine whether the VR headset 410 is properly aligned and / or oriented.

[0125] Various head support mechanisms may be used to “mount” a VR headset on a subject’s head in order to secure the VR headset and / or assist in providing user comfort during use. Head support mechanisms 422 may include one or more physical structure(s) such as strap(s), mount(s), brace(s), padding, or the like. The physical structure(s) may be adjustable (e.g., a hook and loop fastener or elastic strap) or compliant (e.g., foam padding) or both (e.g., an adjustable strap with padding). For example, the VIVE Pro Eye Office VR system includes a replaceable face cushion that provides compliant support around a subject’s eyes for comfort as well as a head pad, adjustment dial, and center strap that collectively secure the system to a subject’s head with the adjustment dial being part of the head pad that sits on the back of the head and center strap that runs over the top of the head. The adjustment dial can adjust the tension of the center strap and the center strap also has a hook and loop fastener for easy mounting and dismounting from the head.

[0126] Additional details about certain illustrative adjustment and / or head support mechanisms that can be included in an embodiment of a VR headset, such as the VR headset 410 shown in Figs. 4A-4C, are provided in the VIVE Pro Eye User guide for the VIVE Pro Eye Office VR system. Other adjustment and / or head support schemes can be used. Furthermore, in certain embodiments, a particular mechanism (e.g., structure) may serve as both an adjustment mechanism and a head support mechanism. For example, a strap may be used to secure a VR headset to a wearer and may also be used to adjust a physical position of the VR headset to the wearer’s eyes.

[0127] Fig. 4C shows a schematic of how the illustrative VR headset 410 can be used to track an eye 401 of a subject. Illumination sources (light sources) LSI, LS2, ..., LSN provide light to the eye 401. Light is received by reflector 416 from the eye 401 after illumination and reflected toward the camera 412 where it is detected and the processed using a headset processor 414 that is part of a controller, which refers to lookup table 418. Optionally, the display 420 simultaneously displays image(s) to the subject, for example to prompt eye movement or a particular focus of the subject in order to orient or track the eye 401. One or more optics 416 (e.g., lenses) may be used to focus or otherwise guide light from the display 420 to the subject. Thedisplay 420 may be considered a portion of one or more optics 416, for example a “lens” of the VR headset 410 may include the display 420 (or portion thereof).

[0128] In the illustrative VR headset 410, the illumination sources LSI, LS2, LSN project a plurality of light beams to the eye 401 on a target zone. The light reflection device 416 receives and reflects the display image IMG of the eye 401 to the camera 412. The controller with headset processor 414 is coupled to the camera 412 and the illumination sources LSI, LS2, . . ., LSN. A headset processor 414 receives the display image IMG and analyzes the contrast ratio of the display image IMG. The headset processor 414 additionally generates the command signal DS through a result of the analysis and controls the turning on or turning off states of each of the illumination sources LSI, LS2, ..., LSN through the command signal DS. The lookup table 418 is configured to store the relationship between the turning on / tuming off states of the illumination sources LSI, LS2, ..., LSN and the field of view information of the eyeball. The lookup table 418 may be implemented as a memory of any suitable form, which will be apparent to those of skill in the art. The lookup table 418 may be external to the controller with the headset processor 414 and coupled to the controller. Alternatively, the lookup table 418 may also be embedded in the controller with the headset processor 414. Further details of additional embodiments of how such a lookup table 418 and controller may be used to control components of a VR headset 410 to track the eye 401 of a subject (e.g., patient) can be found in U.S. Patent No. 10,705,604.

[0129] Systems and methods for tracking movement of one or both eyes of a subject, for example using a virtual- and / or augmented- and / or mixed-reality device (e.g., headset), calibrating and adjusting such a headset, and performing tests with such tracking and / or device are described in International (PCT) Patent Application No. PCT / US22 / 47489, fded Oct. 21, 2022, the disclosure of which is hereby incorporated by reference herein in its entirety.

[0130] Illustrative embodiments of systems and methods disclosed herein were described above with reference to computations performed locally by a computing device, for example included in a VR headset with eye tracking capability. However, computations performed over a network are also contemplated. Fig. 5 shows an illustrative network environment 500 for use in the methods and systems described herein. In brief overview, referring now to Fig. 5, a block diagram of an illustrative cloud computing environment 500 is shown and described. The cloud computing environment 500 may include one or more resource providers 502a, 502b, 502c(collectively, 502). Each resource provider 502 may include computing resources. In some implementations, computing resources may include any hardware and / or software used to process data. For example, computing resources may include hardware and / or software capable of executing algorithms, computer programs, and / or computer applications. In some implementations, illustrative computing resources may include application servers and / or databases with storage and retrieval capabilities. Each resource provider 502 may be connected to any other resource provider 502 in the cloud computing environment 500. In some implementations, the resource providers 502 may be connected over a computer network 508. Each resource provider 502 may be connected to one or more computing device 504a, 504b, 504c (collectively, 504), over the computer network 508.

[0131] The cloud computing environment 500 may include a resource manager 506. The resource manager 506 may be connected to the resource providers 502 and the computing devices 504 over the computer network 508. In some implementations, the resource manager 506 may facilitate the provision of computing resources by one or more resource providers 502 to one or more computing devices 504. The resource manager 506 may receive a request for a computing resource from a particular computing device 504. The resource manager 506 may identify one or more resource providers 502 capable of providing the computing resource requested by the computing device 504. The resource manager 506 may select a resource provider 502 to provide the computing resource. The resource manager 506 may facilitate a connection between the resource provider 502 and a particular computing device 504. In some implementations, the resource manager 506 may establish a connection between a particular resource provider 502 and a particular computing device 504. In some implementations, the resource manager 506 may redirect a particular computing device 504 to a particular resource provider 502 with the requested computing resource.

[0132] Fig. 6 shows an example of a computing device 600 and a mobile computing device 650 that can be used in the methods and systems described in this disclosure. The computing device 600 is intended to represent various forms of digital computers, such as laptops, desktops, workstations, personal digital assistants, servers, blade servers, mainframes, and other appropriate computers. The mobile computing device 650 is intended to represent various forms of mobile devices, such as personal digital assistants, cellular telephones, smart-phones, and other similarcomputing devices. The components shown here, their connections and relationships, and their functions, are meant to be examples only, and are not meant to be limiting.

[0133] The computing device 600 includes a processor 602, a memory 604, a storage device 606, a high-speed interface 608 connecting to the memory 604 and multiple high-speed expansion ports 610, and a low-speed interface 612 connecting to a low-speed expansion port 614 and the storage device 606. Each of the processor 602, the memory 604, the storage device 606, the high-speed interface 608, the high-speed expansion ports 610, and the low-speed interface 612, are interconnected using various busses, and may be mounted on a common motherboard or in other manners as appropriate. The processor 602 can process instructions for execution within the computing device 600, including instructions stored in the memory 604 or on the storage device 606 to display graphical information for a GUI on an external input / output device, such as a display 616 coupled to the high-speed interface 608. In other implementations, multiple processors and / or multiple buses may be used, as appropriate, along with multiple memories and types of memory. Also, multiple computing devices may be connected, with each device providing portions of the necessary operations (e.g., as a server bank, a group of blade servers, or a multi -processor system). Also, multiple computing devices may be connected, with each device providing portions of the necessary operations (e.g., as a server bank, a group of blade servers, or a multi-processor system). Thus, as the term is used herein, where a plurality of functions are described as being performed by “a processor”, this encompasses embodiments wherein the plurality of functions are performed by any number of processors (e.g., one or more processors) of any number of computing devices (e.g., one or more computing devices). Furthermore, where a function is described as being performed by “a processor”, this encompasses embodiments wherein the function is performed by any number of processors (e.g., one or more processors) of any number of computing devices (e.g., one or more computing devices) (e g., in a distributed computing system).

[0134] The memory 604 stores information within the computing device 600. In some implementations, the memory 604 is a volatile memory unit or units. In some implementations, the memory 604 is a non-volatile memory unit or units. The memory 604 may also be another form of computer-readable medium, such as a magnetic or optical disk.

[0135] The storage device 606 is capable of providing mass storage for the computing device 600. In some implementations, the storage device 606 may be or contain a computer- readable medium, such as a hard disk device, an optical disk device, a flash memory or othersimilar solid state memory device, or an array of devices, including devices in a storage area network or other configurations. Instructions can be stored in an information carrier. The instructions, when executed by one or more processing devices (for example, processor 602), perform one or more methods, such as those described above. The instructions can also be stored by one or more storage devices such as computer- or machine-readable mediums (for example, the memory 604, the storage device 606, or memory on the processor 602).

[0136] The high-speed interface 608 manages bandwidth-intensive operations for the computing device 600, while the low-speed interface 612 manages lower bandwidth-intensive operations. Such allocation of functions is an example only. In some implementations, the highspeed interface 608 is coupled to the memory 604, the display 616 (e.g., through a graphics processor or accelerator), and to the high-speed expansion ports 610, which may accept various expansion cards (not shown). In the implementation, the low-speed interface 612 is coupled to the storage device 606 and the low-speed expansion port 614. The low-speed expansion port 614, which may include various communication ports (e.g., USB, Bluetooth®, Ethernet, wireless Ethernet) may be coupled to one or more input / output devices, such as a keyboard, a pointing device, a scanner, or a networking device such as a switch or router, e.g., through a network adapter.

[0137] The computing device 600 may be implemented in a number of different forms, as shown in the figure. For example, it may be implemented as a standard server 620, or multiple times in a group of such servers. In addition, it may be implemented in a personal computer such as a laptop computer 622. It may also be implemented as part of a rack server system 624. Alternatively, components from the computing device 600 may be combined with other components in a mobile device (not shown), such as a mobile computing device 650. Each of such devices may contain one or more of the computing devices 600 and the mobile computing device 650, and an entire system may be made up of multiple computing devices communicating with each other.

[0138] The mobile computing device 650 includes a processor 652, a memory 664, an input / output device such as a display 654, a communication interface 666, and a transceiver 668, among other components. The mobile computing device 650 may also be provided with a storage device, such as a micro-drive or other device, to provide additional storage. Each of the processor 652, the memory 664, the display 654, the communication interface 666, and the transceiver 668,are interconnected using various buses, and several of the components may be mounted on a common motherboard or in other manners as appropriate.

[0139] The processor 652 can execute instructions within the mobile computing device 650, including instructions stored in the memory 664. The processor 652 may be implemented as a chipset of chips that include separate and multiple analog and digital processors. The processor 652 may provide, for example, for coordination of the other components of the mobile computing device 650, such as control of user interfaces, applications run by the mobile computing device 650, and wireless communication by the mobile computing device 650.

[0140] The processor 652 may communicate with a user through a control interface 658 and a display interface 656 coupled to the display 654. The display 654 may be, for example, a TFT (Thin-Film-Transistor Liquid Crystal Display) display or an OLED (Organic Light Emitting Diode) display, or other appropriate display technology. The display interface 656 may comprise appropriate circuitry for driving the display 654 to present graphical and other information to a user. The control interface 658 may receive commands from a user and convert them for submission to the processor 652. In addition, an external interface 662 may provide communication with the processor 652, so as to enable near area communication of the mobile computing device 650 with other devices. The external interface 662 may provide, for example, for wired communication in some implementations, or for wireless communication in other implementations, and multiple interfaces may also be used.

[0141] The memory 664 stores information within the mobile computing device 650. The memory 664 can be implemented as one or more of a computer-readable medium or media, a volatile memory unit or units, or a non-volatile memory unit or units. An expansion memory 674 may also be provided and connected to the mobile computing device 650 through an expansion interface 672, which may include, for example, a SIMM (Single In Line Memory Module) card interface. The expansion memory 674 may provide extra storage space for the mobile computing device 650 or may also store applications or other information for the mobile computing device 650. Specifically, the expansion memory 674 may include instructions to carry out or supplement the processes described above and may include secure information also. Thus, for example, the expansion memory 674 may be provided as a security module for the mobile computing device 650 and may be programmed with instructions that permit secure use of the mobile computing device 650. In addition, secure applications may be provided via the SIMM cards, along withadditional information, such as placing identifying information on the SIMM card in a non- hackable manner.

[0142] The memory may include, for example, flash memory and / or NVRAM memory (non-volatile random-access memory), as discussed below. In some implementations, instructions are stored in an information carrier and, when executed by one or more processing devices (for example, processor 652), perform one or more methods, such as those described above. The instructions can also be stored by one or more storage devices, such as one or more computer- or machine-readable mediums (for example, the memory 664, the expansion memory 674, or memory on the processor 652). In some implementations, the instructions can be received in a propagated signal, for example, over the transceiver 668 or the external interface 662.

[0143] The mobile computing device 650 may communicate wirelessly through the communication interface 666, which may include digital signal processing circuitry where necessary. The communication interface 666 may provide for communications under various modes or protocols, such as GSM voice calls (Global System for Mobile communications), SMS (Short Message Service), EMS (Enhanced Messaging Service), or MMS messaging (Multimedia Messaging Service), CDMA (code division multiple access), TDMA (time division multiple access), PDC (Personal Digital Cellular), WCDMA (Wideband Code Division Multiple Access), CDMA2000, or GPRS (General Packet Radio Service), among others. Such communication may occur, for example, through the transceiver 668 using a radiofrequency. In addition, short-range communication may occur, such as using a Bluetooth®, Wi-Fi™, or other such transceiver (not shown). In addition, a GPS (Global Positioning System) receiver module 670 may provide additional navigation- and location-related wireless data to the mobile computing device 650, which may be used as appropriate by applications running on the mobile computing device 650.

[0144] The mobile computing device 650 may also communicate audibly using an audio codec 660, which may receive spoken information from a user and convert it to usable digital information. The audio codec 660 may likewise generate audible sound for a user, such as through a speaker, e.g., in a handset of the mobile computing device 650. Such sound may include sound from voice telephone calls, may include recorded sound (e.g., voice messages, music files, etc.) and may also include sound generated by applications operating on the mobile computing device 650.

[0145] The mobile computing device 650 may be implemented in a number of different forms, as shown in the figure. For example, it may be implemented as a cellular telephone 680. It may also be implemented as part of a smart-phone 682, personal digital assistant, or other similar mobile device.

[0146] Various implementations of the systems and techniques described here can be realized in digital electronic circuitry, integrated circuitry, specially designed ASICs (application specific integrated circuits), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include implementation in one or more computer programs that are executable and / or interpretable on a programmable system including at least one programmable processor, which may be special or general purpose, coupled to receive data and instructions from, and to transmit data and instructions to, a storage system, at least one input device, and at least one output device.

[0147] These computer programs (also known as programs, software, software applications or code) include machine instructions for a programmable processor and can be implemented in a high-level procedural and / or object-oriented programming language, and / or in assembly / machine language. As used herein, the terms machine-readable medium and computer- readable medium refer to any computer program product, apparatus and / or device (e.g., magnetic discs, optical disks, memory, Programmable Logic Devices (PLDs)) used to provide machine instructions and / or data to a programmable processor, including a machine-readable medium that receives machine instructions as a machine-readable signal. The term machine-readable signal refers to any signal used to provide machine instructions and / or data to a programmable processor.

[0148] To provide for interaction with a user, the systems and techniques described here can be implemented on a computer having a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user and a keyboard and a pointing device (e.g., a mouse or a trackball) by which the user can provide input to the computer. Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form, including acoustic, speech, or tactile input.

[0149] The systems and techniques described here can be implemented in a computing system that includes a back end component (e.g., as a data server), or that includes a middlewarecomponent (e.g., an application server), or that includes a front end component (e.g., a client computer having a graphical user interface or a Web browser through which a user can interact with an implementation of the systems and techniques described here), or any combination of such back end, middleware, or front end components. The components of the system can be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include a local area network (LAN), a wide area network (WAN), and the Internet.

[0150] The computing system can include clients and servers. A client and server are generally remote from each other and typically interact through a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other.

[0151] Methods disclosed herein may be used to determine (e.g., by a processor) an assessment of eye health (e.g., retinal health) of a subject, for example to determine a condition affecting one or both eyes of the subject. Such an assessment may be based at least in part on induction and / or cessation of an optokinetic reflex during a visual function test as described herein [e.g., a period of time it takes for optokinetic reflex to onset and / or cease and / or one or more characteristics (e.g., contrast) at which optokinetic reflex onsets and / or ceases]. Such an assessment may be further based at least in part on a tracked pupil size of either or each eye of a subject. For example, such an assessment may be based at least in part on determined kinetics of pupil constriction and / or dilation determined. A visual function test, such as an optokinetic reflex test, disclosed herein may be combined with one or more other visual function assessments, such as, for example, a radial sweep test and / or a contrast sensitivity test. In some embodiments, a visual function test, such as an optokinetic reflex test, disclosed herein is combined with one or more other of the visual function assessments and / or tests, for example described in International Patent Application No. PCT / US22 / 47489, filed Oct. 21, 2022, and / or International Patent Application No. PCT / US25 / 27461, filed May 2, 2025, each of which is hereby incorporated by reference herein in its entirety. Determining the assessment of retinal health may include determining an existence of and / or a risk of and / or a propensity for and / or a severity of and / or a progression of an vision condition and / or eye condition and / or retina condition for the subject, for example any one or more of the following conditions: diabetic retinopathy (e.g., with or without diabetic macular retinopathy), Stargardt disease, Leber hereditary optic neuropathy (LHON),retinitis pigmentosa, glaucoma, inner nuclear layer disease, geographic atrophy, and macular degeneration [e.g., age-related macular degeneration (AMD) (e.g., early age-related macular degeneration (early AMD), intermediate age-related macular degeneration (intermediate AMD), early / intermediate age-related macular degeneration (early / intermediate AMD), geographic atrophy (GA) (i.e., an advanced form of AMD), dry age-related macular degeneration (dry AMD), wet age-related macular degeneration (wet AMD), and / or neovascular age-related macular degeneration (neovascular AMD))].

[0152] In some embodiments, a visual function test, such as an optokinetic reflex test, as disclosed herein is performed as an initial test (e.g., to establish whether there may be poor visual function, e.g., as compared to a baseline) and a subsequent test, for example a radial sweep test and / or contrast sensitivity test, may then be performed (e.g., if results from the initial test indicate poor visual function, e.g., relative to the baseline). In some embodiments, a visual function test, such as an optokinetic reflex test, disclosed herein may be used as an initial and / or preliminary visual function test, for example as an initial diagnostic and / or monitoring test. In some embodiments, a visual function test, such as an optokinetic reflex test, disclosed herein may be used for fast and / or simple diagnosing and / or monitoring of eye health (e g., visual function). Longer, more elaborate testing may be performed after completion of a visual function test disclosed herein, for example based on one or more test results.

[0153] A visual function test as disclosed herein may be used to diagnose and / or monitor a subject having an eye condition. A subject may be treated with a therapeutic agent (e.g., by administering a therapeutically effective amount of the therapeutic agent) based on the diagnosis and / or monitoring. For example, a subject may be determined to have a worsening severity of an eye condition that is an indication for treatment, for example administration of a therapeutically effective amount of a therapeutic agent. The eye condition may be, for example, diabetic retinopathy (e.g., with or without diabetic macular retinopathy), Stargardt disease, Leber hereditary optic neuropathy (LHON), retinitis pigmentosa, glaucoma, inner nuclear layer disease, geographic atrophy, and age-related macular degeneration (AMD) (e.g., dry age-related macular degeneration (dry AMD), wet age-related macular degeneration (wet AMD), and / or neovascular age-related macular degeneration (neovascular AMD)). The diagnosing and / or monitoring of (e.g., determining of a worsening severity of) (e.g., a progressive worsening of) (e.g., a poor progression of) an eye condition may use a visual function test disclosed herein. In someembodiments, therapeutic effectiveness of a therapeutic agent administered to a subject is determined using a visual function test disclosed herein, for example from test results from the visual function test. Therapeutic effectiveness may be determined for a particular subject. In some embodiments, a visual function test may be used in conjunction with a population of subjects to determine therapeutic effectiveness of a candidate therapeutic agent and / or therapeutic intervention (e.g., in a clinical trial, e.g., to establish whether an endpoint of the trial has been met).

[0154] A therapeutic agent may be (i) a vitamin supplement and / or mineral supplement selected from the group consisting of vitamin C, zinc, vitamin E, copper, beta-carotene, and combinations thereof, (ii) ranibizumab, (iii) faricimab, (iv) brolucizumab, (v) aflibercept, or (vi) pegaptanib, (vii) a complement inhibitor, (viii) a neuroprotective agent, (ix) an anti-inflammatory agent, (x) a free radical scavenger, (xi) an anti-apoptotic agent, (xii) an integrin modulator, (xiii) a gene therapy, or (xiv) a cell therapy. A therapeutic intervention may be laser coagulation therapy.

[0155] In some embodiments a therapeutic agent includes a complement inhibitor complement inhibitor (e.g., a C3 inhibitor or a C5 inhibitor). In some embodiments, a complement inhibitor includes a peptide, protein, antibody, aptamer, or small molecule that binds to a complement component or a biologically active fragment thereof (or to a complex including two or more complement components or biologically active fragments thereof) and inhibits its activity. In some embodiments, the complement component or biologically active fragment thereof is C3, C3a, C3b, C4, C4a, C4b, C5, C5a, C5b, Cl, Clq, factor B, or factor D. In some embodiments, a complement inhibitor includes a nucleic acid, e.g., an siRNA or antisense oligonucleotide, that inhibits expression of a complement component (e.g., C3, C5, factor B, factor D, or Cl).

[0156] In some embodiments, a therapeutic agent is a gene therapy. The gene therapy may genetically modify cells in the eye so as to inhibit expression of a pathogenic gene product, correct a mutation in a gene, deliver a functional copy of a gene to cells that harbor a dysfunctional copy of such gene, or cause cells to express a beneficial nucleic acid or protein.

[0157] In some embodiments, a therapeutic agent is a cell therapy. The cells may include, e.g., stem cells (e.g., induced pluripotent stem cells), stem cell derived cells, retinal pigment epithelial cells, or photoreceptor cells. The cells may replace cells that have been lost to disease or support or supplement the function of remaining cells.

[0158] A method disclosed herein, e.g., a visual function test, can be used as a test (e.g., outcome measure or functional endpoint) for an eye condition. The test may inform and / or dictateif, how (e.g., how much), and / or when (e.g., how often) a treatment, such as a therapeutic agent and / or therapeutic intervention, for the eye condition is administered. A therapeutic agent and / or therapeutic intervention may then be administered in a therapeutically effective amount. Progression of an eye condition (e.g., progression of a severity of the eye condition) may be monitored before and / or after administering a therapeutic agent and / or therapeutic intervention. Progression may inform and / or dictate further administration of a therapeutic agent and / or therapeutic intervention. A method as disclosed herein may be used to assess therapeutic efficacy of a therapeutic agent and / or therapeutic intervention for an eye condition. Subjects that have that eye condition may then be treated with that therapeutic intervention and / or therapeutic agent.

[0159] A subject may be treated (e.g., with a therapeutic agent and / or therapeutic intervention) after having been diagnosed with an eye condition using a method and / or system disclosed herein, after an eye condition of the subject has been monitored using a method and / or system disclosed herein, while an eye condition of the subject is being monitored using a method and / or system disclosed herein, or after it has been determined that (s)he exhibits worsening severity of an eye condition using a method and / or system disclosed herein. The method and / or system may preferably be a visual function test. A method and / or system disclosed herein may be used to diagnose and / or monitor an eye condition. A therapeutic intervention may be laser coagulation therapy.

[0160] A therapeutic agent administered to treat an eye condition after or during diagnosis and / or monitoring and / or determining of worsening severity may be, for example, (i) a vitamin supplement and / or mineral supplement selected from the group consisting of vitamin C, zinc, vitamin E, copper, beta-carotene, and combinations thereof, (ii) ranibizumab, (iii) faricimab, (iv) brolucizumab, (v) aflibercept, (vi) pegaptanib, (vii) a complement inhibitor, (viii) a neuroprotective agent, (ix) an anti-inflammatory agent, (x) a free radical scavenger, (xi) an anti- apoptotic agent, (xii) an integrin modulator, (xiii) a gene therapy, or (xiv) a cell therapy. In some embodiments, a therapeutic agent includes a complement inhibitor. In some embodiments, a complement inhibitor includes a peptide, protein, antibody, aptamer, or small molecule that binds to a complement component or a biologically active fragment thereof (or to a complex including two or more complement components or biologically active fragments thereof) and inhibits its activity. In some embodiments, the complement component or biologically active fragment thereof is C3, C3a, C3b, C4, C4a, C4b, C5, C5a, C5b, Cl, Clq, factor B, or factor D. In someembodiments, a complement inhibitor includes a nucleic acid, e.g., an siRNA or antisense oligonucleotide, that inhibits expression of a complement component (e.g., C3, C5, factor B, factor D, or Cl). In some embodiments, a therapeutic agent is a gene therapy. The gene therapy may genetically modify cells in the eye so as to inhibit expression of a pathogenic gene product, correct a mutation in a gene, deliver a functional copy of a gene to cells that harbor a dysfunctional copy of such gene, or cause cells to express a beneficial nucleic acid or protein. In some embodiments, a therapeutic agent is a cell therapy. The cells may include, e.g., stem cells (e.g., induced pluripotent stem cells), stem cell derived cells, retinal pigment epithelial cells, or photoreceptor cells. The cells may replace cells that have been lost to disease or support or supplement the function of remaining cells.

[0161] Without limitation to the foregoing description, the following is an enumerated list of non-limiting exemplary embodiments included in the present disclosure. Those of ordinary skill in the art will appreciate that one or more features discussed above may be included with or incorporated into any of the following numbered embodiments to form additional embodiments.1. A method for performing a visual function test on a subject (e g., a contrast sensitivity test and / or a photostress recovery test) (e.g., an optokinetic reflex test) (e.g., using a virtual- and / or augmented- and / or mixed-reality device, e.g., a VR headset with eye tracking capability), the method comprising: rendering and displaying (e.g., on a head-mounted {e.g. face-mounted} display of the VR headset) to the subject, by a processor of a computing device, an animated graphic in a field of view of the subj ect (e.g., displaying the animated graphic in a virtual and / or augmented scene in the field of view); and during display of the animated graphic, (e.g., automatically) tracking movement (e.g., by the processor, e.g., using eye tracking software and / or hardware, e.g., using the VR headset with eye tracking capability, e.g., using an eye tracking camera with associated software and / or illumination source) of one or both eyes of the subject to detect and / or quantify an optokinetic reflex of the subject in response to the animated graphic [e.g., wherein the tracking comprises capturing images of one or both eyes of the subject (e.g., as still images or video)].2. The method of embodiment 1 , wherein the animated graphic comprises a series of spaced-apart shapes (e.g., a series of vertical lines or rectangles, e.g., a grating) that appear to move (e.g., move together) in a particular direction (e.g., a horizontal direction or a vertical direction) (e.g., wherein the spaced-apart shapes are translucent) (e.g., wherein the spaced- apart shapes have an opacity in a range of 20%-80%) [e.g., wherein the spaced-apart shapes are grayscale (e.g., black)].3. The method of embodiment 2, wherein the series of spaced-apart shapes appear to move with respect to (e.g., over) a background [e.g., a stationary background (e.g., over a scenic graphic that serves as the stationary background)] (e.g., wherein the background is a live view or virtual rendering of a field of view of the subject outside of an augmented- and / or mixed- reality device).4. The method of embodiment 2 or embodiment 3, wherein the series of spaced-apart shapes appear to move with respect to (e.g., inside of) a stationary frame (e.g., that appears as window) (e.g., wherein the background is a live view or virtual rendering of a field of view of the subject outside of an augmented- and / or mixed-reality device).5. The method of any one of embodiments 1-5, comprising rendering and displaying the animated graphic with progressively changing (e.g., reducing or increasing) contrast (e.g., between the series of spaced-apart shapes and the background) (e.g., wherein contrast is progressively changed continuously or in discrete steps) (e.g., at least until the subject ceases to have an optokinetic reflex in response to the motion) (e.g., until the background and the spaced-apart shapes are indistinguishable).6. The method of embodiment 5, wherein the rendering and displaying the animated graphic with the progressively changing contrast comprises changing a size of the spaced-apart shapes [e.g., by reducing or expanding at least one dimension (e.g., width) of the spaced-apart shapes (e.g., until the spaced-apart shapes disappear or become contiguous, respectively)].7. The method of embodiment 5 or embodiment 6, wherein the rendering and displaying the animated graphic with the progressively changing contrast comprises changing an opacity of the spaced-apart shapes and / or the background [e.g., by reducing an opacity of the spacedapart shapes (e.g., until the shapes become transparent)].8. The method of any one of embodiments 5-7, wherein the rendering and displaying the animated graphic with the progressively changing contrast comprises simultaneously progressively graying or de-graying the background and / or the spaced-apart shapes [e.g., until an entire field of view of the subject becomes gray (e.g., uniformly gray)] [e.g., uniformly graying (e.g., both the background and the spaced-apart shapes)].9. The method of any one of embodiments 5-8, wherein the rendering and displaying the animated graphic with the progressively changing contrast comprises progressively graying or de-graying at least a portion of a field of view of the subject [e.g., until an entire field of view of the subject becomes gray (e.g., uniformly gray)] (e.g., uniformly graying) (e.g., at least until the subject ceases to have an optokinetic reflex in response to the motion).10. The method of any one of embodiments 5-9, wherein the rendering and displaying the animated graphic with the progressively changing contrast comprises changing at least one color of the spaced-apart shapes to correspond to one or more colors of the background and / or changing at least one color of the background to correspond to one or more colors of the spaced-apart shapes.11. The method of any one of embodiments 5-10, wherein the rendering and displaying the animated graphic with the progressively changing contrast comprises lightening and / or darkening the background, the spaced-apart shapes, or both to reduce the contrast therebetween.12. The method of any one of embodiments 2-11, comprising rendering and displaying, by the processor, progressively changing spatial frequency of the spaced-apart shapes in the animated graphic while separately progressively changing the contrast (e.g., changingthickness of the spaced-apart shapes while progressively greying the background graphic and / or contrast widget) [e.g., changing distance between (e.g., spacing of) the spaced-apart shapes while progressively greying the background graphic and / or contrast widget] (e.g., changing thickness of the spaced-apart shapes while progressively greying at least a portion of a field of view of the subject) (e.g., changing relative speed of the spaced-apart shapes while progressively greying at least a portion of a field of view of the subject).13. The method of any one of embodiments 2-12, comprising rendering and displaying to the subject, by the processor, a progressively changing (e.g., a reducing or an increasing): (i) relative speed of the spaced-apart shapes (e.g., a speed of the spaced-apart shapes in relation to the static background), and / or (ii) distance between spaced-apart shapes, and / or (iii) size (e.g., thickness) of the spaced-apart shapes (e g., thickness of stripes) [e.g., one, two, or all three of the preceding (i), (ii), and (iii)] (e.g., wherein the progressively changing relative speed and / or distance between spaced-apart shapes and / or size of the spaced-apart shapes is rendered in discrete steps) (e.g., wherein the progressively changing relative speed and / or distance between spaced-apart shapes and / or size of the spaced-apart shapes is rendered as a continuous change, e.g., gradual change) (e.g., wherein the progressive changing of the relative speed and / or distance between spaced-apart shapes and / or size of the spaced-apart shapes results in a changing spatial frequency between the background and the spaced-apart shapes).14. The method of any one of embodiments 2-13, comprising progressively changing, by the processor, a spatial frequency of the spaced-apart shapes (e.g., by changing thickness of, relative speed of, and / or distance between (e.g., spacing of) the spaced-apart shapes) while tracking the movement of one or both eyes of the subject.15. The method of any one of embodiments 2-14, comprising rendering and displaying, by the processor, the animated graphic at a plurality of combinations of (i) contrast (e g., of the contrast widget relative to the background graphic) and (ii) spatial frequency of the spaced- apart shapes while tracking the movement of one or both eyes of the subject.16. The method of embodiment 15, comprising determining and / or recording, by the processor, a contrast and spatial frequency for each of the combinations at which the subject begins to have or ceases to have an optokinetic reflex in response to appearance of motion.17. The method of any one of embodiments 2-16, comprising rendering and displaying, by the processor, the animated graphic while progressively changing both contrast of the spacedapart shapes relative to the background and spatial frequency of the spaced-apart shapes, also while tracking the movement of one or both eyes of the subject.18. The method of any one of embodiments 1-17, automatically determining, by the processor, when the optokinetic reflex of the subject ceases or begins (e.g., automatically determining when the contrast is low enough for the optokinetic reflex to cease or high enough for the optokinetic reflex to begin) based on the tracking.19. The method of any one of embodiments 1-18, further comprising determining, by the processor, an optokinetic nystagmus profile for the subject based at least in part on the tracked eye movement.20. The method of any one of embodiments 1-19, further comprising determining an abnormality (e g., an abnormal optokinetic reflex) or condition (e.g., retinal condition) of the subject based at least in part on the tracked eye movement.21. The method of any one of embodiments 1-20, wherein the animated graphic is rendered and displayed using a virtual- and / or augmented- and / or mixed-reality device [e.g., on a headmounted (e.g., face-mounted) display of a VR headset] (e.g., wherein the device comprises the processor) [e.g., a consumer device (e.g., VR headset)].22. The method of embodiment 21, wherein the device has eye tracking capability and the tracking movement of one or both eyes of the subject is performed with the device.23. The method of any one of embodiments 1-22, wherein the method is performed without calibration (e.g., without calibrating the device) (e.g., without eye tracking calibration) [e.g., without any user-related (e.g., subject-related) calibration].24. The method of any one of embodiments 1-23, wherein the method is performed without determining a point of a gaze of the subject.25. The method of any one of embodiments 1-24, comprising determining a contrast sensitivity function for the subject based on the detection and / or quantification of the optokinetic reflex of the subject.26. A system (e.g., a virtual- and / or augmented- and / or mixed-reality device system) comprising a processor and a memory having instructions stored thereon, the instructions executable by the processor to perform the method of any one of embodiments 1 to 25.27. A system for conducting a visual function test (e.g., an optokinetic reflex assessment) on a subject using a virtual- and / or augmented- and / or mixed-reality device (e.g., VR headset with eye tracking capability), the system comprising: a processor of a computing device; and a memory having instructions stored thereon, wherein the instructions, when executed by the processor, cause the processor to perform the method of any one of embodiments 1 to 25.28. The system of embodiment 27, comprising the virtual- and / or augmented- and / or mixed-reality device for performing the visual function test.29. The system of embodiment 28, wherein the device is a consumer VR headset.30. The system of any one of embodiments 27-29, comprising an eye-tracking camera (e.g., wherein the headset comprises the eye-tracking camera).31. The system of embodiment 30, comprising an illumination source (e.g., wherein the headset comprises the illumination source).32. A method for performing a visual function test on a subject (e.g., a contrast sensitivity test and / or a photostress recovery test) (e.g., an optokinetic reflex test) (e.g., using a virtual- and / or augmented- and / or mixed-reality device, e.g., a VR headset with eye tracking capability), the method comprising: providing (e.g., rendering and displaying) to a subject, by a processor, a background graphic [e.g., a scenic graphic (e.g., of a nature scene, a background scene, or any other scene, realistic or abstract] (e.g., a background color and / or uniform background) (e.g., wherein the background graphic is a live view or virtual rendering of a field of view of the subject outside of an augmented- and / or mixed-reality device); during provision (e.g., display) of the background graphic, rendering and displaying to the subject, by the processor, a contrast widget comprising a plurality of spaced-apart shapes [e.g., lines or rectangles (e.g., a series of lines or rectangles)] (e.g., a grating) disposed over (e.g., overlaid on) or in (e.g., interspersed within) the background graphic such that the contrast widget appears to be in motion (e.g., relative motion to the background graphic) (e.g., in fast, medium, or slow motion, e.g., in a horizontal or vertical direction); and tracking (e.g., automatically) (e.g., using the processor or a second processor) [e.g., using eye tracking software and / or hardware (e.g., using a VR headset with eye tracking capability) (e.g., using an eye tracking camera, e.g., with associated software and / or illumination source)] movement of one or both eyes of the subject in response to the contrast widget disposed over or in the background graphic [e.g., wherein the tracking comprises capturing images of one or both eyes of the subject (e.g., as still images or video)].33. The method of embodiment 32, wherein tracking the movement of the one or both eyes of the subject comprises tracking (e.g., detecting and / or quantifying) an optokinetic reflex (optokinetic nystagmus) of the subject caused by the apparent motion (e.g., animation of the contrast widget).34. The method of embodiment 32 or embodiment 33, wherein the background graphic is animated (e.g., appears to the subject to be in motion) [e.g., and the contrast widget is not animated (e.g., appears to the subject to be still)] [e.g., is provided in a framing graphic (e.g., representing a window)].35. The method of any one of embodiments 32-34, wherein the contrast widget is animated (e.g., appears to the subject to be in motion) [e.g., and the background graphic is not animated (e.g., appears to the subject to be still)] [e.g., is provided in a framing graphic (e.g., representing a window)].36. The method of any one of embodiments 32-35, wherein the motion is of a sufficient speed as to induce an optokinetic reflex in the subject.37. The method of any one of embodiments 32-36, wherein the background graphic appears stationary behind a moving series of lines or rectangles (e.g., a moving grating).38. The method of any one of embodiments 32-37, comprising rendering and displaying to the subject, by the processor, progressively changing (e.g., reducing or increasing) contrast between the background graphic and the contrast widget while tracking the movement of one or both eyes of the subject (e.g., wherein contrast is progressively changed continuously or in discrete steps) (e.g., at least until the subject ceases to have an optokinetic reflex in response to the motion) (e.g., until the background graphic and the contrast widget are indistinguishable).39. The method of embodiment 38, wherein the rendering and displaying the progressively changing contrast comprises changing a size of the spaced-apart shapes [e.g., by reducing or expanding at least one dimension (e.g., width) of the spaced-apart shapes (e.g., until the spaced- apart shapes disappear or become contiguous, respectively)].40. The method of embodiment 38 or embodiment 39, wherein the rendering and displaying the progressively changing contrast comprises changing an opacity of the spaced-apart shapes and / or the background graphic [e g., by reducing an opacity of the spaced-apart shapes (e.g., until the shapes become transparent)].41. The method of any one of embodiments 38-40, wherein the rendering and displaying the progressively changing contrast comprises simultaneously progressively graying or degraying the background graphic and / or the contrast widget [e.g., until an entire field of view of the subject becomes gray (e.g., uniformly gray)] [e.g., uniformly graying (e.g., both the background graphic and the contrast widget)].42. The method of any one of embodiments 38-41, wherein the rendering and displaying the progressively changing contrast comprises progressively graying or de-graying at least a portion of a field of view of the subject [e.g., until an entire field of view of the subject becomes gray (e.g., uniformly gray)] (e.g., uniformly graying).43. The method of any one of embodiments 38-42, wherein the rendering and displaying the progressively changing contrast comprises changing at least one color of the contrast widget to correspond or no longer correspond to one or more colors of the background graphic and / or changing at least one color of the background graphic to correspond to one or more colors of the contrast widget (e.g., until the background graphic and the contrast widget are indistinguishable).44. The method of any one of embodiments 38-43, wherein the rendering and displaying the progressively changing contrast comprises lightening and / or darkening the background graphic, the contrast widget, or both to change (e.g., reduce or increase) the contrast therebetween.45. The method of any one of embodiments 38-44, comprising recording, by the processor, a period of time that elapsed before the subject has or no longer has an optokinetic reflex in response to the contrast widget disposed over or in the background graphic and / or when the subject has or no longer has an optokinetic reflex in response to the contrast widget disposed over or in the background graphic.46. The method of any one of embodiments 38-45, wherein the rendering and displaying the progressively changing contrast comprises progressively graying or de-graying the background graphic and / or the contrast widget.47. The method of any one of embodiments 38-46, wherein the contrast progressively changes over a period of no more than 20 seconds (e.g., no more than 10 seconds or no more than 5 seconds).48. The method of any one of embodiments 38-47, comprising rendering and displaying, by the processor, progressively changing spatial frequency of the spaced-apart shapes while separately progressively changing the contrast (e.g., changing thickness of the spaced-apart shapes while progressively greying the background graphic and / or contrast widget) [e.g., changing distance between (e.g., spacing of) the spaced-apart shapes while progressively greying the background graphic and / or contrast widget] (e.g., changing thickness of the spaced- apart shapes while progressively greying at least a portion of a field of view of the subject) (e.g., changing relative speed of the spaced-apart shapes while progressively greying at least a portion of a field of view of the subject).49. The method of any one of embodiments 32-48, wherein tracking the movement of one or both eyes comprises determining, by the processor, when an optokinetic reflex of the subject begins and / or ceases (e.g., in response to the change of contrast) (e.g., automatically determining when the contrast is low enough for the optokinetic reflex to cease).50. The method of any one of embodiments 32-49, comprising recording, by the processor, a contrast (e.g., a relative contrast between the background graphic and the contrast widget) [e.g., in a two-dimensional measurement space (e.g., having contrast dimension and a spatial frequency dimension)] at which the subject begins to have or no longer has an optokinetic reflex.51 . The method of any one of embodiments 32-50, comprising rendering and displaying to the subject, by the processor, a progressively changing (e.g., a reducing or an increasing): (i) relative speed of the contrast widget (e.g., a speed of the animated contrast widget in relation to the static background graphic), and / or (ii) distance between spaced-apart shapes of the (e.g., animated) contrast widget, and / or (iii) size (e.g., thickness) of the spaced-apart shapes of the (e.g., animated) contrast widget (e.g., thickness of stripes) [e.g., one, two, or all three of the preceding (i), (ii), and (iii)] (e.g., wherein the progressively changing relative speed and / or distance between spaced-apart shapes and / or size of the spaced-apart shapes is rendered in discrete steps) (e.g., wherein the progressively changing relative speed and / or distance between spaced-apart shapes and / or size of the spaced-apart shapes is rendered as a continuous change, e.g., gradual change) (e.g., wherein the progressive changing of the relative speed and / or distance between spaced-apart shapes and / or size of the spaced-apart shapes results in a changing spatial frequency between the background graphic and the contrast widget).52. The method of any one of embodiments 32-51, comprising progressively changing, by the processor, a spatial frequency of the contrast widget [e.g., by changing size (e.g., thickness) of, relative speed of, and / or distance between (e.g., spacing of) the spaced-apart shapes] while tracking the movement of one or both eyes of the subject.53. The method of any one of embodiments 32-52, comprising rendering and displaying, by the processor, the background graphic and the contrast widget such that the contrast widget appears to be in motion at a plurality of combinations of (i) contrast (e.g., of the contrast widget relative to the background graphic) and (ii) spatial frequency of the spaced-apart shapes while tracking the movement of one or both eyes of the subject.54. The method of embodiment 53, comprising determining and / or recording, by the processor, a contrast and spatial frequency for each of the combinations at which the subject begins to have or ceases to have an optokinetic reflex in response to appearance of motion.55. The method of any one of embodiments 32-54, comprising providing and / or rendering and displaying, by the processor, the background graphic and the contrast widget such that thecontrast widget appears to be in motion while progressively changing both contrast of the contrast widget relative to the background graphic and spatial frequency of the spaced-apart shapes, also while tracking the movement of one or both eyes of the subject.56. The method of any one of embodiments 32-55, comprising determining, by the processor, an optokinetic nystagmus profile for the subject based at least in part on the tracking.57. The method of embodiment 56, comprising comparing, by the processor, one or more characteristics of the motion to the nystagmus profile.58. The method of embodiment 57, comprising determining, by the processor, (i) for at least one point in time, whether the subject can see the contrast widget, (ii) when an optokinetic reflex in the one or both eyes of the subject begins and / or ceases, (iii) a contrast level [e.g., a relative contrast level between the background graphic and the contrast widget, a contrast level (e.g., opacity) of the contrast widget, or a gray level of at least a portion of a field of view of the subject] (e.g., a contrast for a specific spatial frequency) (e.g., at a spatial frequency of spaced-apart shapes in the contrast widget) [e.g., in a two-dimensional measurement space (e.g., having contrast dimension and a spatial frequency dimension)] at which an optokinetic reflex in the one or both eyes of the subject begins and / or ceases, or (iv) a combination thereof, based at least in part on a result of the comparing (e.g., based on a contrast level between the background graphic and the contrast widget determined by the comparison).59. The method of embodiment 57 or embodiment 58, comprising determining (e.g., by the processor) an abnormality or condition (e.g., retinal condition) of the subject based at least in part on a result of the comparing.60. The method of any one of embodiments 32-59, comprising determining (e.g., by the processor) an abnormality (e.g., an abnormal optokinetic reflex) or condition (e.g., retinal condition) of the subject based at least in part on the tracking.61. The method of any one of embodiments 32-60, wherein the appearance of motion occurs over a period of time of no more than 20 seconds (e.g., no more than 10 seconds or no more than 5 seconds).62. The method of any one of embodiments 32-61, wherein the motion is a unidirectional motion (e.g., in a horizontal or vertical direction) (e.g., wherein the contrast widget appears to move in a horizontal or vertical direction over the background graphic while the background graphic remains stationary).63. The method of any one of embodiments 32-62, wherein the motion is a horizontal motion.64. The method of any one of embodiments 32-63, wherein the shapes are translucent (e.g., have an opacity in a range of 20% - 80%).65. The method of any one of embodiments 32-64, wherein the shapes are grayscale (e.g., are dark).66. The method of any one of embodiments 32-65, wherein the shapes are rendered and displayed with an initial luminance of at least 5 cd / m2and no more than 30 cd / m2.67. The method of any one of embodiments 32-66, wherein the background graphic is provided (e.g., displayed) within a virtual and / or augmented scene in a field of view of the subject.68. The method of any one of embodiments 32-67, wherein the contrast widget is rendered and displayed and the background graphic is provided using a virtual- and / or augmented- and / or mixed-reality device [e.g., on a head-mounted (e.g., face-mounted) display of a VR headset] (e.g., wherein the device comprises the processor) [e.g., a consumer device (e.g., VR headset)].69. The method of embodiment 68, wherein the device has eye tracking capability and the tracking movement of one or both eyes of the subject is performed with the device.70. The method of any one of embodiments 32-69, wherein the method is performed without calibration (e.g., without calibrating the device) (e.g., without eye tracking calibration) [e.g., without any user-related (e.g., subject-related) calibration],71. The method of any one of embodiments 32-70, wherein the method is performed without determining a point of a gaze of the subject.72. The method of any one of embodiments 32-71, comprising determining a contrast sensitivity function for the subject based on the tracking of movement of one or both eyes of the subject.73. A system (e.g., a virtual- and / or augmented- and / or mixed-reality device system), comprising a processor and a memory having instructions stored thereon, the instructions executable by the processor to perform the method of any one of embodiments 32-72.74. The system of embodiment 73, comprising a virtual- and / or augmented- and / or mixed- reality device operable to be used in performance of the method (e.g., comprising the processor and the memory).75. The system of embodiment 74, wherein the device is a consumer VR headset with eye tracking capability.76. A system for optokinetic reflex testing of a subject [e.g., using a virtual- and / or augmented- and / or mixed-reality device (e.g., VR headset with eye tracking capability)], the system comprising: a processor of a computing device; anda memory having instructions stored thereon, wherein the instructions, when executed by the processor, cause the processor to perform the method of any one of embodiments 32 to 72.77. The system of embodiment 76, comprising the virtual- and / or augmented- and / or mixed-reality device for testing optokinetic reflex.78. The system of embodiment 77, comprising an eye-tracking camera (e.g., wherein the headset comprises the eye-tracking camera).79. The system of embodiment 78, comprising an illumination source (e.g., wherein the headset comprises the illumination source).80. A method comprising: changing (e.g., reducing or increasing) contrast in a field of view of a subject using a virtual- and / or augmented- and / or mixed-reality device such that one or both eyes of the subject begin to exhibit or cease to exhibit an optokinetic reflex; and tracking movement of the one or both eyes during the contrast change.81. A method compri sing : inducing an optokinetic reflex in one or both eyes of a subject using a virtual- and / or augmented- and / or mixed-reality device (e.g., by displaying an animated graphic); changing (e.g., reducing or increasing) contrast in a field of view of the subject using the device while the one or both eyes are exhibiting the optokinetic reflex; and tracking movement of the one or both eyes during the contrast change.82. The method of embodiment 80 or embodiment 81, wherein tracking the movement comprises determining when the optokinetic reflex begins or ceases due to the contrast change in the field of view.83. The method of any one of embodiments 80-82, wherein the virtual- and / or augmented- and / or mixed-reality device is a VR headset.84. The method of any one of embodiments 80-83, wherein the device performs the tracking (e.g., has eye tracking capability).85. A method comprising: changing (e.g., reducing or increasing) contrast in a field of view of a subject such that one or both eyes of the subject begin to exhibit or cease to exhibit an optokinetic reflex; and tracking movement of the one or both eyes during the contrast change.86. A method comprising: inducing an optokinetic reflex in one or both eyes of a subject (e.g., with an animated graphic); changing (e.g., reducing or increasing) contrast in a field of view of the subject while the one or both eyes are exhibiting the optokinetic reflex; and tracking movement of the one or both eyes during the contrast change.87. The method of embodiment 85 or embodiment 86, wherein tracking the movement comprises determining when the optokinetic reflex begins or ceases due to the contrast change in the field of view.88. The method of embodiment of any one of embodiments 85-87, wherein the contrast is changed in the field of view (e.g., and the optokinetic reflex is induced) using a virtual- and / or augmented- and / or mixed-reality device.89. The method of embodiment 88, wherein the device performs the tracking (e.g., has eye tracking capability).90. A method for performing a visual function test on a subject (e g., a contrast sensitivity test and / or a photostress recovery test) (e.g., an optokinetic reflex test) (e.g., using a virtual-and / or augmented- and / or mixed-reality device, e.g., a VR headset with eye tracking capability), the method comprising: rendering and displaying (e.g., on a head-mounted {e.g. face-mounted} display of the VR headset) to the subject, by a processor of a computing device, an animated graphic in a field of view of the subj ect (e.g., displaying the animated graphic in a virtual and / or augmented scene in the field of view); and during display of the animated graphic, (e.g., automatically) tracking movement (e.g., by the processor, e.g., using eye tracking software and / or hardware, e.g., using the VR headset with eye tracking capability, e.g., using an eye tracking camera with associated software and / or illumination source) of one or both eyes of the subject in response to the animated graphic [e.g., wherein the tracking comprises capturing images of one or both eyes of the subject (e.g., as still images or video)].91. The method of any one of embodiments 1-25, 32-72, 80-90, comprising diagnosing the subject as having an eye condition based at least in part on a result of the visual function test.92. The method of embodiment 91, wherein the eye condition is a member selected from the group consisting of diabetic retinopathy, Stargardt disease, Leber hereditary optic neuropathy (LHON), retinitis pigmentosa, glaucoma, inner nuclear layer disease, geographic atrophy, and macular degeneration.93. The method of embodiment 91 or embodiment 92, comprising administering to the subject (a) a therapeutically effective amount of a therapeutic agent for treatment of the eye condition and / or (b) a therapeutic intervention for treatment of the eye condition based on the diagnosis.94. The method of embodiment 93, comprising administering the therapeutic agent, wherein the therapeutic agent comprises (i) a vitamin supplement and / or mineral supplement selected from the group consisting of vitamin C, zinc, vitamin E, copper, beta-carotene, and combinations thereof, (ii) ranibizumab, (iii) faricimab, (iv) brolucizumab, (v) aflibercept, or (vi) pegaptanib, (vii) a complement inhibitor, (viii) a neuroprotective agent, (ix) an anti-inflammatory agent, (x) a free radical scavenger, (xi) an anti-apoptotic agent, (xii) an integrin modulator, (xiii) a gene therapy, and / or (xiv) a cell therapy.95. The method of any one of embodiments 1-25, 32-72, 80-94, comprising monitoring an eye condition of the subject based at least in part on a result of the visual function test.96. The method of embodiment 95, wherein the monitoring comprises determining of a worsening severity of and / or a progressive worsening of the eye condition.97. The method of embodiment 95 or embodiment 96, wherein the eye condition is a member selected from the group consisting of diabetic retinopathy, Stargardt disease, Leber hereditary optic neuropathy (LHON), retinitis pigmentosa, glaucoma, inner nuclear layer disease, geographic atrophy, and macular degeneration.98. The method of any one of embodiments 95-97, comprising administering to the subject (a) a therapeutically effective amount of a therapeutic agent for treatment of the eye condition and / or (b) a therapeutic intervention for treatment of the eye condition based on the monitoring.99. The method of embodiment 98, comprising administering the therapeutic agent, wherein the therapeutic agent comprises (i) a vitamin supplement and / or mineral supplement selected from the group consisting of vitamin C, zinc, vitamin E, copper, beta-carotene, and combinations thereof, (ii) ranibizumab, (iii) faricimab, (iv) brolucizumab, (v) aflibercept, or (vi) pegaptanib, (vii) a complement inhibitor, (viii) a neuroprotective agent, (ix) an antiinflammatory agent, (x) a free radical scavenger, (xi) an anti-apoptotic agent, (xii) an integrin modulator, (xiii) a gene therapy, and / or (xiv) a cell therapy.100. The method of any one of embodiments 1-25, 32-72, 80-99, wherein the subject has an eye condition, and wherein the method comprises monitoring the subject for progression of the eye condition based at least in part on a result of the visual function test.101. The method of embodiment 100, wherein the eye condition is a member selected from the group consisting of diabetic retinopathy, Stargardt disease, Leber hereditary optic neuropathy (LHON), retinitis pigmentosa, glaucoma, inner nuclear layer disease, geographic atrophy, and macular degeneration.102. A method of treating a subj ect that has been determined to have an eye condition and / or a worsening of an eye condition using a method according to any one of embodiments 1-25, 32-72, 80-101, the method comprising administering to the subject (a) a therapeutically effective amount of a therapeutic agent for treatment of the eye condition and / or (b) a therapeutic intervention for treatment of the eye condition.103. The method of embodiment 102, comprising administering the therapeutic agent, wherein the therapeutic agent comprises (i) a vitamin supplement and / or mineral supplement selected from the group consisting of vitamin C, zinc, vitamin E, copper, beta-carotene, and combinations thereof, (ii) ranibizumab, (iii) faricimab, (iv) brolucizumab, (v) aflibercept, or (vi) pegaptanib, (vii) a complement inhibitor, (viii) a neuroprotective agent, (ix) an antiinflammatory agent, (x) a free radical scavenger, (xi) an anti-apoptotic agent, (xii) an integrin modulator, (xiii) a gene therapy, and / or (xiv) a cell therapy.104. The method of embodiment 102 or embodiment 103, wherein the eye condition is a member selected from the group consisting of diabetic retinopathy, Stargardt disease, Leber hereditary optic neuropathy (LHON), retinitis pigmentosa, glaucoma, inner nuclear layer disease, geographic atrophy, and macular degeneration.

[0162] In this application, unless otherwise clear from context or otherwise explicitly stated, (i) the term “a” may be understood to mean “at least one”; (ii) the term “or” may be understood to mean “and / or”; (iii) the terms “comprising” and “including” may be understood to encompass itemized components or steps whether presented by themselves or together with one or more additional components or steps; (iv) the terms “about” and “approximately” may be understood to permit standard variation as would be understood by those of ordinary skill in the relevant art; and (v) where ranges are provided, endpoints are included. In certain embodiments,the term "approximately" or "about" refers to a range of values that fall within 25%, 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, or less in either direction (greater than or less than) of the stated reference value unless otherwise stated or otherwise evident from the context (except where such number would exceed 100% of a possible value).

[0163] Certain embodiments of the present disclosure were described above. It is, however, expressly noted that the present disclosure is not limited to those embodiments, but rather the intention is that additions and modifications to what was expressly described in the present disclosure are also included within the scope of the disclosure. Moreover, it is to be understood that the features of the various embodiments described in the present disclosure were not mutually exclusive and can exist in various combinations and permutations, even if such combinations or permutations were not made express, without departing from the spirit and scope of the disclosure. The disclosure has been described in detail with particular reference to certain embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the claimed invention.

Claims

What is claimed is:

1. A method for performing a visual function test on a subject, the method comprising: rendering and displaying to the subject, by a processor of a computing device, an animated graphic in a field of view of the subject; and during display of the animated graphic, tracking movement of one or both eyes of the subject to detect and / or quantify an optokinetic reflex of the subject in response to the animated graphic.

2. The method of claim 1, wherein the animated graphic comprises a series of spacedapart shapes that appear to move in a particular direction.

3. The method of claim 2, wherein the series of spaced-apart shapes appear to move with respect to a background.

4. The method of claim 2, wherein the series of spaced-apart shapes appear to move with respect to a stationary frame.

5. The method of claim 1, comprising rendering and displaying the animated graphic with progressively changing contrast.

6. The method of claim 5, wherein the rendering and displaying the animated graphic with the progressively changing contrast comprises changing a size of the spaced-apart shapes.

7. The method of claim 5, wherein the rendering and displaying the animated graphic with the progressively changing contrast comprises changing an opacity of the spaced-apart shapes and / or the background.

8. The method of claim 5, wherein the rendering and displaying the animated graphic with the progressively changing contrast comprises simultaneously progressively graying or degraying the background and / or the spaced-apart shapes.

9. The method of claim 5, wherein the rendering and displaying the animated graphic with the progressively changing contrast comprises progressively graying or de-graying at least a portion of a field of view of the subject.

10. The method of claim 5, wherein the rendering and displaying the animated graphic with the progressively changing contrast comprises changing at least one color of the spaced-apart shapes to correspond to one or more colors of the background and / or changing at least one color of the background to correspond to one or more colors of the spaced-apart shapes.

11. The method of claim 5, wherein the rendering and displaying the animated graphic with the progressively changing contrast comprises lightening and / or darkening the background, the spaced-apart shapes, or both to reduce the contrast therebetween.

12. The method of claim 2, comprising rendering and displaying, by the processor, progressively changing spatial frequency of the spaced-apart shapes in the animated graphic while separately progressively changing the contrast.

13. The method of claim 2, comprising rendering and displaying to the subject, by the processor, a progressively changing: (i) relative speed of the spaced-apart shapes, and / or (ii) distance between spaced-apart shapes, and / or (iii) size of the spaced-apart shapes.

14. The method of claim 2, comprising progressively changing, by the processor, a spatial frequency of the spaced-apart shapes while tracking the movement of one or both eyes of the subject.

15. The method of claim 2, comprising rendering and displaying, by the processor, the animated graphic at a plurality of combinations of (i) contrast and (ii) spatial frequency of the spaced-apart shapes while tracking the movement of one or both eyes of the subject.

16. The method of claim 15, comprising determining and / or recording, by the processor, a contrast and spatial frequency for each of the combinations at which the subject begins to have or ceases to have an optokinetic reflex in response to appearance of motion.

17. The method of claim 2, comprising rendering and displaying, by the processor, the animated graphic while progressively changing both contrast of the spaced-apart shapes relative to the background and spatial frequency of the spaced-apart shapes, also while tracking the movement of one or both eyes of the subject.

18. The method of claim 1, automatically determining, by the processor, when the optokinetic reflex of the subject ceases or begins based on the tracking.

19. The method of claim 1, further comprising determining, by the processor, an optokinetic nystagmus profile for the subject based at least in part on the tracked eye movement.

20. The method of claim 1, further comprising determining an abnormality or condition of the subject based at least in part on the tracked eye movement.

21. The method of claim 1, wherein the animated graphic is rendered and displayed using a virtual- and / or augmented- and / or mixed-reality device.

22. The method of claim 21 , wherein the device has eye tracking capability and the tracking movement of one or both eyes of the subject is performed with the device.

23. The method of claim 1, wherein the method is performed without calibration.

24. The method of claim 1, wherein the method is performed without determining a point of a gaze of the subject.

25. The method of claim 1, comprising determining a contrast sensitivity function for the subject based on the detection and / or quantification of the optokinetic reflex of the subject.

26. A system comprising a processor and a memory having instructions stored thereon, the instructions executable by the processor to perform the method of claim 1.

27. A system for conducting a visual function test on a subject using a virtual- and / or augmented- and / or mixed-reality device, the system comprising: a processor of a computing device; and a memory having instructions stored thereon, wherein the instructions, when executed by the processor, cause the processor to perform the method of claim 1.

28. The system of claim 27, comprising the virtual- and / or augmented- and / or mixed- reality device for performing the visual function test.

29. The system of claim 28, wherein the device is a consumer VR headset.

30. The system of claim 27, comprising an eye-tracking camera.

31. The system of claim 30, comprising an illumination source.

32. A method for performing a visual function test on a subject, the method comprising: providing to a subject, by a processor, a background graphic; during provision of the background graphic, rendering and displaying to the subject, by the processor, a contrast widget comprising a plurality of spaced-apart shapes disposed over or in the background graphic such that the contrast widget appears to be in motion; and tracking movement of one or both eyes of the subject in response to the contrast widget disposed over or in the background graphic.

33. The method of claim 32, wherein tracking the movement of the one or both eyes of the subject comprises tracking an optokinetic reflex (optokinetic nystagmus) of the subject caused by the apparent motion.

34. The method of claim 32, wherein the background graphic is animated.

35. The method of claim 32, wherein the contrast widget is animated.

36. The method of claim 32, wherein the motion is of a sufficient speed as to induce an optokinetic reflex in the subject.

37. The method of claim 32, wherein the background graphic appears stationary behind a moving series of lines or rectangles.

38. The method of claim 32, comprising rendering and displaying to the subject, by the processor, progressively changing contrast between the background graphic and the contrast widget while tracking the movement of one or both eyes of the subject.

39. The method of claim 38, wherein the rendering and displaying the progressively changing contrast comprises changing a size of the spaced-apart shapes.

40. The method of claim 38, wherein the rendering and displaying the progressively changing contrast comprises changing an opacity of the spaced-apart shapes and / or the background graphic.

41. The method of claim 38, wherein the rendering and displaying the progressively changing contrast comprises simultaneously progressively graying or de-graying the background graphic and / or the contrast widget.

42. The method of claim 38, wherein the rendering and displaying the progressively changing contrast comprises progressively graying or de-graying at least a portion of a field of view of the subject.

43. The method of claim 38, wherein the rendering and displaying the progressively changing contrast comprises changing at least one color of the contrast widget to correspond or no longer correspond to one or more colors of the background graphic and / or changing at least one color of the background graphic to correspond to one or more colors of the contrast widget.

44. The method of claim 38, wherein the rendering and displaying the progressively changing contrast comprises lightening and / or darkening the background graphic, the contrast widget, or both to change the contrast therebetween.

45. The method of claim 38, comprising recording, by the processor, a period of time that elapsed before the subject has or no longer has an optokinetic reflex in response to the contrast widget disposed over or in the background graphic and / or when the subject has or no longer has an optokinetic reflex in response to the contrast widget disposed over or in the background graphic.

46. The method of claim 38, wherein the rendering and displaying the progressively changing contrast comprises progressively graying or de-graying the background graphic and / or the contrast widget.

47. The method of claim 38, wherein the contrast progressively changes over a period of no more than 20 seconds.

48. The method of claim 38, comprising rendering and displaying, by the processor, progressively changing spatial frequency of the spaced-apart shapes while separately progressively changing the contrast.

49. The method of claim 32, wherein tracking the movement of one or both eyes comprises determining, by the processor, when an optokinetic reflex of the subject begins and / or ceases.

50. The method of claim 32, comprising recording, by the processor, a contrast at which the subject begins to have or no longer has an optokinetic reflex.

51. The method of claim 32, comprising rendering and displaying to the subject, by the processor, a progressively changing: (i) relative speed of the contrast widget, and / or (ii) distance between spaced-apart shapes of the contrast widget, and / or (iii) size of the spacedapart shapes of the contrast widget.

52. The method of claim 32, comprising progressively changing, by the processor, a spatial frequency of the contrast widget while tracking the movement of one or both eyes of the subject.

53. The method of claim 32, comprising rendering and displaying, by the processor, the background graphic and the contrast widget such that the contrast widget appears to be in motion at a plurality of combinations of (i) contrast and (ii) spatial frequency of the spaced- apart shapes while tracking the movement of one or both eyes of the subject.

54. The method of claim 53, comprising determining and / or recording, by the processor, a contrast and spatial frequency for each of the combinations at which the subject begins to have or ceases to have an optokinetic reflex in response to appearance of motion.

55. The method of claim 32, comprising providing and / or rendering and displaying, by the processor, the background graphic and the contrast widget such that the contrast widget appears to be in motion while progressively changing both contrast of the contrast widget relative to the background graphic and spatial frequency of the spaced-apart shapes, also while tracking the movement of one or both eyes of the subject.

56. The method of claim 32, comprising determining, by the processor, an optokinetic nystagmus profile for the subject based at least in part on the tracking.

57. The method of claim 56, comprising comparing, by the processor, one or more characteristics of the motion to the nystagmus profile.

58. The method of claim 57, comprising determining, by the processor, (i) for at least one point in time, whether the subject can see the contrast widget, (ii) when an optokinetic reflex in the one or both eyes of the subject begins and / or ceases, (iii) a contrast level at which an optokinetic reflex in the one or both eyes of the subject begins and / or ceases, or (iv) a combination thereof, based at least in part on a result of the comparing.

59. The method of claim 57, comprising determining an abnormality or condition of the subject based at least in part on a result of the comparing.

60. The method of claim 32, comprising determining an abnormality or condition of the subject based at least in part on the tracking.

61. The method of claim 32, wherein the appearance of motion occurs over a period of time of no more than 20 seconds.

62. The method of claim 32, wherein the motion is a unidirectional motion.

63. The method of claim 32, wherein the motion is a horizontal motion.

64. The method of claim 32, wherein the shapes are translucent.

65. The method of claim 32, wherein the shapes are grayscale.

66. The method of claim 32, wherein the shapes are rendered and displayed with an initial luminance of at least 5 cd / m2and no more than 30 cd / m2.

67. The method of claim 32, wherein the background graphic is provided within a virtual and / or augmented scene in a field of view of the subject.

68. The method of claim 32, wherein the contrast widget is rendered and displayed and the background graphic is provided using a virtual- and / or augmented- and / or mixed-reality device.

69. The method of claim 68, wherein the device has eye tracking capability and the tracking movement of one or both eyes of the subject is performed with the device.

70. The method of claim 32, wherein the method is performed without calibration.

71. The method of claim 32, wherein the method is performed without determining a point of a gaze of the subject.

72. The method of claim 32, comprising determining a contrast sensitivity function for the subject based on the tracking of movement of one or both eyes of the subject.

73. A system, comprising a processor and a memory having instructions stored thereon, the instructions executable by the processor to perform the method of claim 32.

74. The system of claim 73, comprising a virtual- and / or augmented- and / or mixed-reality device operable to be used in performance of the method.

75. The system of claim 74, wherein the device is a consumer VR headset with eye tracking capability.

76. A system for optokinetic reflex testing of a subject, the system comprising: a processor of a computing device; anda memory having instructions stored thereon, wherein the instructions, when executed by the processor, cause the processor to perform the method of claim 32.

77. The system of claim 76, comprising the virtual- and / or augmented- and / or mixed- reality device for testing optokinetic reflex.

78. The system of claim 77, comprising an eye-tracking camera.

79. The system of claim 78, comprising an illumination source.

80. A method comprising: changing contrast in a field of view of a subject using a virtual- and / or augmented- and / or mixed-reality device such that one or both eyes of the subject begin to exhibit or cease to exhibit an optokinetic reflex; and tracking movement of the one or both eyes during the contrast change.

81. The method of claim 80, wherein tracking the movement comprises determining when the optokinetic reflex begins or ceases due to the contrast change in the field of view.

82. The method of claim 80, wherein the virtual- and / or augmented- and / or mixed-reality device is a VR headset.

83. The method of claim 80, wherein the device performs the tracking.

84. A method comprising: inducing an optokinetic reflex in one or both eyes of a subject using a virtual- and / or augmented- and / or mixed-reality device; changing contrast in a field of view of the subject using the device while the one or both eyes are exhibiting the optokinetic reflex; and tracking movement of the one or both eyes during the contrast change.

85. The method of claim 81, wherein tracking the movement comprises determining when the optokinetic reflex begins or ceases due to the contrast change in the field of view.

86. The method of claim 81, wherein the virtual- and / or augmented- and / or mixed-reality device is a VR headset.

87. The method of claim 81, wherein the device performs the tracking.

88. A method comprising: changing contrast in a field of view of a subject such that one or both eyes of the subject begin to exhibit or cease to exhibit an optokinetic reflex; and tracking movement of the one or both eyes during the contrast change.

89. The method of claim 88, wherein tracking the movement comprises determining when the optokinetic reflex begins or ceases due to the contrast change in the field of view.

90. The method of claim 88, wherein the contrast is changed in the field of view using a virtual- and / or augmented- and / or mixed-reality device.

91. The method of claim 90, wherein the device performs the tracking.

92. A method comprising: inducing an optokinetic reflex in one or both eyes of a subject; changing contrast in a field of view of the subject while the one or both eyes are exhibiting the optokinetic reflex; and tracking movement of the one or both eyes during the contrast change.

93. The method of claim 92, wherein tracking the movement comprises determining when the optokinetic reflex begins or ceases due to the contrast change in the field of view.

94. The method of claim 92, wherein the contrast is changed in the field of view using a virtual- and / or augmented- and / or mixed-reality device.

95. The method of claim 94, wherein the device performs the tracking.

96. A method for performing a visual function test on a subject, the method comprising: rendering and displaying to the subject, by a processor of a computing device, an animated graphic in a field of view of the subject; and during display of the animated graphic, tracking movement of one or both eyes of the subject in response to the animated graphic.

97. The method of claim 1, 32, 80, 84, 88, 92, or 96, comprising diagnosing the subject as having an eye condition based at least in part on a result of the visual function test.

98. The method of claim 97, wherein the eye condition is a member selected from the group consisting of diabetic retinopathy, Stargardt disease, Leber hereditary optic neuropathy (LHON), retinitis pigmentosa, glaucoma, inner nuclear layer disease, geographic atrophy, and macular degeneration.

99. The method of claim 97 or claim 98, comprising administering to the subject (a) a therapeutically effective amount of a therapeutic agent for treatment of the eye condition and / or (b) a therapeutic intervention for treatment of the eye condition based on the diagnosis.

100. The method of claim 99, comprising administering the therapeutic agent, wherein the therapeutic agent comprises (i) a vitamin supplement and / or mineral supplement selected from the group consisting of vitamin C, zinc, vitamin E, copper, beta-carotene, and combinations thereof, (ii) ranibizumab, (iii) faricimab, (iv) brolucizumab, (v) aflibercept, or (vi) pegaptanib, (vii) a complement inhibitor, (viii) a neuroprotective agent, (ix) an anti-inflammatory agent, (x) a free radical scavenger, (xi) an anti-apoptotic agent, (xii) an integrin modulator, (xiii) a gene therapy, and / or (xiv) a cell therapy.

101. The method of claim 1, 32, 80, 84, 88, 92, or 96, comprising monitoring an eye condition of the subject based at least in part on a result of the visual function test.

102. The method of claim 101, wherein the monitoring comprises determining of a worsening severity of and / or a progressive worsening of the eye condition.

103. The method of claim 101 or claim 102, wherein the eye condition is a member selected from the group consisting of diabetic retinopathy, Stargardt disease, Leber hereditary optic neuropathy (LHON), retinitis pigmentosa, glaucoma, inner nuclear layer disease, geographic atrophy, and macular degeneration.

104. The method of any one of claims 101-103, comprising administering to the subject (a) a therapeutically effective amount of a therapeutic agent for treatment of the eye condition and / or (b) a therapeutic intervention for treatment of the eye condition based on the monitoring.

105. The method of claim 104, comprising administering the therapeutic agent, wherein the therapeutic agent comprises (i) a vitamin supplement and / or mineral supplement selected from the group consisting of vitamin C, zinc, vitamin E, copper, beta-carotene, and combinations thereof, (ii) ranibizumab, (iii) faricimab, (iv) brolucizumab, (v) aflibercept, or (vi) pegaptanib, (vii) a complement inhibitor, (viii) a neuroprotective agent, (ix) an anti-inflammatory agent, (x) a free radical scavenger, (xi) an anti-apoptotic agent, (xii) an integrin modulator, (xiii) a gene therapy, and / or (xiv) a cell therapy.

106. The method of claim 1, 32, 80, 84, 88, 92, or 96, wherein the subject has an eye condition, and wherein the method comprises monitoring the subject for progression of the eye condition based at least in part on a result of the visual function test.

107. The method of claim 106, wherein the eye condition is a member selected from the group consisting of diabetic retinopathy, Stargardt disease, Leber hereditary optic neuropathy (LHON), retinitis pigmentosa, glaucoma, inner nuclear layer disease, geographic atrophy, and macular degeneration.

108. A method of treating a subject that has been determined to have an eye condition and / or a worsening of an eye condition using a method according to claim 1, 32, 80, 84, 88, 92, or 96, the method comprising administering to the subject (a) a therapeutically effective amount of a therapeutic agent for treatment of the eye condition and / or (b) a therapeutic intervention for treatment of the eye condition.

109. The method of claim 108, comprising administering the therapeutic agent, wherein the therapeutic agent comprises (i) a vitamin supplement and / or mineral supplement selected from the group consisting of vitamin C, zinc, vitamin E, copper, beta-carotene, and combinations thereof, (ii) ranibizumab, (iii) faricimab, (iv) brolucizumab, (v) aflibercept, or (vi) pegaptanib, (vii) a complement inhibitor, (viii) a neuroprotective agent, (ix) an anti-inflammatory agent, (x) a free radical scavenger, (xi) an anti-apoptotic agent, (xii) an integrin modulator, (xiii) a gene therapy, and / or (xiv) a cell therapy.

110. The method of claim 108 or claim 109, wherein the eye condition is a member selected from the group consisting of diabetic retinopathy, Stargardt disease, Leber hereditary optic neuropathy (LHON), retinitis pigmentosa, glaucoma, inner nuclear layer disease, geographic atrophy, and macular degeneration.

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