Afferent pupillary defect testing in VR headsets

Abstract

The goal is to improve the efficiency of visual field testing. A virtual reality (VR) headset-based electronic system can be used to perform afferent pupillary defect (APD) testing, which can improve the sensitivity, consistency, and ease of application of APD testing. Other aspects are also described.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This non-provisional patent application claims the benefit of the earlier filing date of U.S. Provisional Patent Application No. 63 / 479,856, filed January 13, 2023, which is incorporated herein by reference in its entirety.

[0002] One aspect of the present disclosure relates to a portable, head-mounted device that can be used to detect afferent pupillary defect in a user's eye. [Background technology]

[0003] Traditionally, afferent pupil defect (APD) testing is performed manually by trained eye care professionals. Manual APD testing can be used to detect whether APD is present, but the degree or severity of APD is qualitatively determined by the practitioner. Therefore, the results or sensitivity of the test vary from practitioner to practitioner. Summary of the Invention

[0004] One aspect of the disclosure herein is a virtual reality (VR) headset-based electronic system that administers afferent pupil defect (APD) tests to a user. These systems can improve sensitivity, consistency, and ease of administering the test in a variety of ambient light environments in a more efficient (less time-consuming) manner. The results of the APD test can then be used, for example, by an eye care professional to diagnose health problems in the user that may require further testing or recommended treatment.

[0005] The above summary does not include an exhaustive list of all aspects of the present disclosure. The present disclosure is intended to include all systems and methods that may be implemented from any suitable combination of the various aspects summarized above, as well as those disclosed in the Detailed Description below and particularly pointed out in the Claims section. Such combinations may have advantages not described in the above summary. [Brief explanation of the drawings]

[0006] Certain aspects of the disclosure herein are illustrated by way of example, and not limitation, in the figures of the accompanying drawings, where like references indicate like elements. It should be noted that references to "an" or "one" aspect in the present disclosure do not necessarily refer to the same aspect, but rather mean at least one. Also, for the sake of brevity and to reduce the total number of figures, a given figure may be used to illustrate features of more than one aspect of the disclosure, and not all elements of a figure may be required for a given aspect. [Figure 1] FIG. 1 is a diagram of an exemplary virtual reality (VR) headset-based system for afferent pupillary defect (APD) testing. [Figure 2] 2 is a flow diagram of a method for APD testing using, for example, the system of FIG. 1. [Figure 3] 1 shows an exemplary pupillary response recorded as part of an APD testing method, demonstrating the absence of an afferent pupillary response. [Figure 4] 1 shows an exemplary pupil response recorded as part of an APD testing method, showing that no afferent pupillary response was detected, but slight anisocoria was detected. DETAILED DESCRIPTION OF THE INVENTION

[0007] Some aspects of the present disclosure will now be described with reference to the accompanying drawings. Wherever the shape, relative position, and other aspects of the described parts are not explicitly defined, the scope of the present invention is not limited to only the parts shown for illustrative purposes only. Also, while many details are set forth, it will be understood that some aspects of the disclosure can be practiced without these details. In other instances, well-known circuits, structures, and techniques have not been shown in detail in order not to obscure an understanding of this description.

[0008] FIG. 1 is a diagram of an exemplary virtual reality (VR) headset-based system that can be used for APD testing. The system consists of a VR headset 1 with a wired or wireless communication network interface for communicating data with an external computing device 9, such as a tablet computer, laptop computer, or the like. A human operator, such as an eye care professional (ECP), can simply interact with software running on one or more microelectronic data processors (generally, "processors") in the system to conduct the test. Once the software is launched or initialized, it can automatically (without operator input) conduct the test by controlling various electronic and optical components of the VR headset 1. The software may have components running on a processor within the VR headset 1 and components running on a processor that is part of the external computing device 9 while the VR headset 1 is worn on the user's eyes as shown. Some of these software components may run on either the VR headset 1 or the external computing device 9. The software may interact with the operator through a graphical user interface using the touchscreen of the external computing device 9, including presenting the results of the test.

[0009] VR headset 1 may have a goggle-like form factor, as shown, to block all ambient lighting outside VR headset 1 and create a dimmed environment around the user's eyes (independent of ambient lighting outside VR headset 1). VR headset 1 may consist of a left visible light display 3 coupled to a left compartment 5 worn over the user's left eye and a right visible light display 4 coupled to a right compartment 6 worn over the user's right eye. The left and right compartments are configured, e.g., molded and opaque, so that (once VR headset 1 is worn over the user's eyes) the user cannot view the right display 4 using only the left eye and the user cannot view the left display 3 using only the right eye. Also, the left and right displays need not be separate display screens but instead can be left and right halves of a single display screen. The displays may be implemented using technology that provides sufficient display resolution or pixel density, such as liquid crystal display technology, organic light-emitting diode technology, etc. Although not shown, there may be eyecups over each of the left and right displays that contain optical elements (e.g., lenses) that function to give the user the illusion that objects viewed by the user in the displays (which may be displayed in 2D or 3D) are at a greater distance than the actual distance from the user's eyes to the displays, thereby allowing for more comfortable viewing. The headset may also incorporate trial lenses or some other adjustable refractive optics to accommodate multiple patients with different refractive errors.

[0010] The VR headset 1 also has a non-visible light based eye tracking subsystem 8, for example an infrared pupil tracking subsystem, whose output eye tracking data can be interpreted by the processor to independently track left and right eye position, detect blinks, and detect pupil size or diameter in a manner invisible to the user. In one embodiment, the tracking subsystem is an infrared pupil tracking subsystem that generates images of the left and right eye pupils and enables the processor to record the size of the left and right pupils over time with a resolution of less than one millimeter.

[0011] The system has a processor configured to perform the APD test by software or by instructions stored on a machine-readable medium such as solid-state memory when the headset is worn on the user's eyes. The term "processor" may refer to one or more microelectronic devices that are part of the external computing device 9, one or more microelectronic devices within the housing of the VR headset 1, or a combination of microelectronics within the external computing device 9, the VR headset 1, and possibly another computing device in communication with each other via a digital communication interface. For example, the processor may be external to the VR headset 1 and receive tracking data from the eye tracking subsystem via a wired or wireless communication network interface. The processor may be configured to send a signal to an additional display, such as a display screen of the external computing device 9, to display the progress or results of the APD test.

[0012] An APD test may proceed as follows, with reference to the operations shown in the flow diagram of FIG. 2 . Note that, herein, unless clearly implied by context or explicitly stated, the operations of a method or process need not occur sequentially in the order illustrated or described, as in some cases, two or more operations may overlap in time or occur in a different order. Once the headset is placed on the user's eyes, as seen in FIG. 1 , for example, the method begins in operation 11 by the processor signaling the left or right visible light display to simultaneously display a background in extremely low light, e.g., less than 0.5 cd / m 2 . Thus, the background may be dark or absent across the entire display screen, e.g., obtained by signaling a zero pixel intensity value across the entire display screen. The background may fully dilate the pupil of a normal eye, e.g., to a size of 4-8 mm.

[0013] Next, in operation 13, the processor signals only one of the left or right displays, e.g., the left display, to display a stimulus of a predetermined luminance (e.g., a region of light that may span the entire screen). In other words, the other display, in this example the right display, remains the background. The stimulus may be designed to constrict the pupil of a normal eye, e.g., to a size of 2-4 mm. The stimulus may be displayed, for example, for 1 / 2 to 2 seconds before the display transitions back to the background or dark phase. This momentary event is also referred to herein as a flash. Figure 1 illustrates this example in which only the left eye (OS) is flashed with the stimulus.

[0014] Next, in operation 14, the processor signals the left and right visible light displays to simultaneously display the background. Resuming the background now allows both pupils to dilate again in preparation for the next stimulus interval. This intermediate background interval may be, for example, 3-7 seconds long.

[0015] Next, in operation 16, the processor signals only the other of the left or right display (not the display in operation 13) to display the stimulus. In this example, the right display now shows the stimulus while the left display remains background (no stimulus is shown).

[0016] Optionally, the processor then proceeds to operation 17 and signals the left and right displays to simultaneously show only the background (no stimulus shown).

[0017] During these operations 11-17, as the display transitions between the dark background phase and the light stimulus phase, the processor records the size of the left and right pupils over time based on tracking data from the eye-tracking subsystem (operation 18). The recorded sizes may also be stored as a dataset or results of the test associated with the user. For example, the processor may be configured to display the recorded sizes of the left and right pupils over time, or the determined rates at which the left and right pupils constrict and recover, as part of a history of afferent pupillary defect tests administered to the user.

[0018] The results of the test, which show changes in pupil size over time synchronized with the timing of the dark and light phases, can be interpreted by the operator in a variety of ways. For example, if the user has normal eyes, both eyes will dilate during the dark background phase, and then when only the left eye is flashed (in the light stimulus phase in act 13, where only the left display transitions from low light to high light and the right display remains low light), there should be symmetric constriction of both the left and right pupils. If both eyes constrict symmetrically when only the right eye is flashed again (act 16), the test is normal (i.e., no afferent pupillary defect is detected).

[0019] FIG. 3 shows an example of a pupil response or pupil size data set recorded as part of an APD testing method that may be displayed to an operator (e.g., on the display of external computing device 9). Pupil size for both eyes is plotted against time; in this example, pupil size is given in pixels, which can be easily converted to distance in millimeters based on the resolution of the eye-tracking subsystem (6.4 pixels / mm in this example). At the end of the initial background interval, the left eye is flashed around the 2.5-second mark in the first stimulus interval (operation 13), and then the right eye is flashed around the 11-second mark in the second stimulus interval (operation 16), with the intermediate background interval extending from approximately the 3-second mark to the 10-second mark. The background interval and stimulus interval are shaded differently in the plot to make them distinguishable, making it easier for the operator to interpret the test results. From the plotted pupil size, it can be seen that both pupils constrict symmetrically during both flash intervals. The operator may interpret this as indicating no afferent pupillary response. In contrast, if the pupil size data indicates that one eye is constricting less than the other, the operator may interpret this as indicating APD (due to retinal or optic nerve disease).

[0020] 2 test is to configure the processor to omit the intermediate background interval added in act 14 (between acts 13 and 16). In other words, only the left eye is flashed, and then immediately thereafter only the right eye is flashed. In another variation, either the ending background interval in act 17 or the beginning background interval in act 11 can be omitted.

[0021] The processor may be further configured to interpret the pupil size data set to flag conditions that may be interpreted by an operator as indicative of anisocoria. For example, FIG. 4 shows an exemplary pupil size data set (recorded as part of the APD testing method described above) indicating the absence of an afferent pupillary response in the dark but slight anisocoria. The processor may be configured to mark the data set if the recorded sizes of the left and right pupils differ by more than a threshold over the same time interval of at least 1 second during which a background is displayed. During every background interval (dark phase), the processor compares the recorded left and right pupil sizes to each other, and if they differ by more than a threshold, the processor asserts a notice or flag as part of the data set indicating such a finding.

[0022] The processor may also be configured to analyze the pupil size data set and mark the data set if the left and right pupils do not constrict symmetrically over the same time interval, e.g., at least ½ second, in response to the stimulus being displayed during that time interval.

[0023] In another aspect, the processor is further configured to interpret the recorded pupil size to determine a rate at which the left and right pupils constrict and then recover in an intermediate background interval, and store the determined rates as further data associated with the user.

[0024] In yet another aspect of the disclosure herein, the processor may be further configured to perform the following test and interpret the resulting pupil size dataset to flag conditions that may be interpreted by an operator as indicative of pupil anisocoria in light: The test may begin by signaling both the left and right displays to simultaneously display a stimulus for a given time interval (stimulus phase or light phase). During the light phase, the processor records the sizes of the left and right pupils based on tracking data from the eye-tracking subsystem over the given time interval and stores the recorded sizes as a separate dataset associated with the user. The processor interprets this dataset and marks it whenever the recorded sizes of the left and right pupils differ by more than a threshold value.

[0025] In yet another aspect, the processor is configured to signal the left or right display to illuminate the left or right eye at a mesopic level while displaying a target stimulus (object or symbol), and the operator may prompt the user to identify the target stimulus. The mesopic level produced by the display may be within a luminance range of 0.01 to 3.0 cd / m².

[0026] While particular embodiments have been described and shown in the accompanying drawings, it will be understood that these are merely illustrative of the broad invention and not limiting, and since various other modifications may occur to those skilled in the art, the invention is not limited to the specific constructions and arrangements shown and described. Accordingly, this description is to be regarded as illustrative rather than limiting.

Claims

1. 1. A virtual reality (VR) headset-based system, comprising: a VR headset, the VR headset comprising: a left visible light display; a left compartment for wearing over the user's left eye; a right visible light display; a right compartment for wearing over the user's right eye, the left compartment and the right compartment being configured such that when the headset is worn over the user's eye, i) the user cannot see the right display using only their left eye, and ii) the user cannot see the left display using only their right eye; and a non-visible light based gaze tracking subsystem that generates tracking data for the left eye and the right eye; a processor, when the headset is placed on the user's eyes, i) signaling the left display and the right light display to simultaneously display a background in very low light; and ii) signaling only one of the left display or the right display to display a stimulus of a predetermined luminance; and iii) signaling only the other of the left display or the right display to display the stimulus; iv) a processor configured to, during i)-iii), record left and right pupil sizes over time based on the tracking data from the eye tracking subsystem, and store the recorded sizes as a data set associated with the user; and Equipped with A virtual reality (VR) headset-based system.

2. 2. The system of claim 1, wherein the processor is further configured to add an intermediate background interval by signaling the left display and the right display to simultaneously display the background after ii) and before iii).

3. 3. The system of claim 2, wherein the processor is further configured to interpret the recorded sizes to determine a rate at which the left and right pupils constrict and then recover during the intermediate background interval, and to store the determined rates as further data associated with the user.

4. The processor:

4. The system of claim 1, further configured to mark the data set if the recorded sizes of the left and right pupils differ by more than a threshold value over the same time interval of at least 1 second during which the background is displayed.

5. The processor:

5. The system of claim 1, further configured to mark the data set if the left and right pupils do not constrict symmetrically for the same time interval of at least ½ second in response to a stimulus being displayed.

6. The processor: signaling the left display and the right display to simultaneously display the stimuli for a given time interval; recording sizes of the left and right pupils based on the tracking data from the eye-tracking subsystem over the given time interval, and storing the recorded sizes as a separate data set associated with the user; marking the separate data set if the recorded sizes of the left pupil and the right pupil differ by more than a threshold; The system according to any one of claims 1 to 5, further configured to:

7. 7. The system of claim 1, wherein the processor is further configured to signal the left display or the right display to illuminate the left eye or the right eye at a mesopic level while displaying a target stimulus.

8. 4. The system of claim 3, wherein the processor is configured to display the recorded sizes of the left and right pupils over time or the determined rates at which the left and right pupils constrict and recover as part of a history of afferent pupillary defect tests administered to the user.

9. The system of any one of claims 1 to 8, wherein the background is not dark or light.

10. The system of any one of claims 1 to 9, wherein the stimulus is a light field.

11. The system of any one of claims 1 to 10, wherein the stimulus is displayed for between 1 / 2 second and 2 seconds.

12. The system of any one of claims 1 to 11, wherein the recorded sizes of the left and right pupils over time have a resolution of less than one millimeter.

13. 13. The system of claim 1, wherein the processor is external to the VR headset, the VR headset comprising a wired or wireless communication network interface, and wherein the tracking data from the eye tracking subsystem is transmitted to the processor via the communication network interface.

14. The system of any one of claims 1 to 13, wherein the eye-tracking subsystem is an infrared pupil-tracking subsystem that generates images of the pupils of the left and right eyes.

15. 15. The system of claim 1, wherein the VR headset comprises one or more light sensors that can be used to detect ambient light levels inside the left and right compartments, and the processor is configured to record the ambient light levels in the left and right compartments that represent the contribution of external light while the user is wearing the VR headset.

16. 1. A method for pupillary disorder testing, comprising: i) sending a signal to the left display and the right optical display of the VR headset to simultaneously display a dark background; ii) sending a signal to only one of the left display or the right display to display a light stimulus; iii) sending a signal to the other of the left display or the right display only to display the light stimulus; iv) during i)-iii), recording left and right pupil sizes of a user of the VR headset over time based on the tracking data from the eye-tracking subsystem within the VR headset, and storing the recorded sizes as a data set associated with the user; 1. A method for testing for pupillary disorders, comprising:

17. 17. The method of claim 16, further comprising adding an intermediate background interval by signaling the left display and the right display to simultaneously display the dark background after ii) and before iii).

18. 18. The method of claim 16 or 17, further comprising marking the data set if the recorded sizes of the left pupil and the right pupil differ by more than a threshold over the same time interval of at least 1 second during which the background is displayed.

19. 19. The method of claim 16, further comprising marking the data set if the left pupil and the right pupil do not constrict symmetrically for the same time interval of at least ½ second in response to a stimulus being displayed.

20. signaling the left and right displays to simultaneously display the stimuli for a given time interval; recording sizes of the left and right pupils based on the tracking data from the eye tracking subsystem over the given time interval and storing the recorded sizes as a separate data set associated with the user; marking the separate data set if the recorded sizes of the left and right pupils differ by more than a threshold; The method of any one of claims 16 to 19, further comprising:

21. 21. The method of claim 16, further comprising displaying the recorded sizes of the left and right pupils over time or the determined rates at which the left and right pupils constrict and recover as part of a history of afferent pupillary defect tests administered to the user.

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