Improved systems and methods for testing peripheral vision

Abstract

Systems and methods according to the present principles use a touch screen based device, such as a tablet computer or other computer incorporating a touch screen, to perform testing and receive input / output, It will be appreciated that any such device may be used so long as a display, a means for user input, and a means for eye tracking are provided, and the display screen is large enough to effectively test the visual field.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 327,388, filed April 5, 2023, the contents of which are incorporated herein by reference. [Background technology]

[0002] Peripheral vision, in contrast to central vision, concerns the ability to see objects and movements that are at the edge of one's field of vision, i.e., not in one's direct line of sight.

[0003] The peripheral retina of the eye is generally responsible for peripheral vision. Loss of peripheral vision is called "tunnel vision" and can be associated with glaucoma or other deterioration of the retina or optic nerve. Therefore, one potential test for glaucoma includes testing peripheral vision, and such testing has been performed by perimetry testing, which is a visual field test. Summary of the Invention [Problem to be solved by the invention]

[0004] However, such are generally associated with complex capital equipment, referred to as "perimeter," which is generally bulky and not suitable for portability. As the trend toward value-based outcomes-based healthcare continues, portable, inexpensive equipment is generally highly desirable. [Means for solving the problem]

[0005] In one implementation, systems and methods according to the present principles use a touch screen based device, such as a tablet computer or other computer incorporating a touch screen, to perform testing and receive input / output, It will be appreciated that any such device may be used so long as a display, a means for user input, and a means for eye tracking are provided, and the display screen is large enough to effectively test the visual field.

[0006] In one aspect, the present invention is directed to a method of testing a user's visual field, the method including the steps of displaying a stationary element on a touch screen user interface; detecting whether one or more eyes of the user are fixated on the stationary element; if the user's eyes or more are not fixated on the stationary element, displaying instructions to the user to look at the stationary element; if the user's eyes or more are fixated on the stationary element, displaying a flash element at a position within the peripheral vision at a first given time for the time that the user's eyes or more are fixated on the stationary element; receiving a signal indicating that the user saw the flash element while the user's eyes or more were fixated on the stationary element; repeating the steps of displaying the flash element at the same or another position within the peripheral vision and receiving the signal for one or more subsequent given times; and determining a representation of the user's visual field based on the received signal.

[0007] Implementations of the invention may include one or more of the following: Receiving a signal may include receiving a tap or click indication from a user interface or receiving an audio indication from a user interface. The method may further include determining whether receiving a signal occurred within a first duration following a first given time, and determining the indication may be further based on determining whether receiving a signal occurred within a first duration following a first given time. Determining the indication may include calculating a visual field. The method may further include displaying an indication of the calculated visual field on a user interface. The method may further include determining a measure associated with glaucoma based on the calculated visual field. The method may further include determining a measure associated with an ocular or visual or other defect or disease based on the calculated visual field. The ocular or visual defect or disease may involve peripheral vision. The method may further include determining whether an eye movement occurred during fixation, and if so, determining a type of eye movement detected as part or all of the movement. The method may further include basing part of determining the indication on the determined presence and type of eye movement.

[0008] In another aspect, the invention is directed to a computer readable medium including instructions for causing a computing environment to perform the methods described above. The instructions may be downloadable from an online resource.

[0009] In another aspect, the present invention is directed to a method of testing a user's visual field, the method including the steps of detecting a user input indicating that a visual field test should be initiated; displaying a first element on a touch screen user interface; detecting whether one or more eyes of the user are looking at the first element and determining a first duration between the display of the first element and the detecting step; repeating the displaying and detecting steps of whether the user's eyes are looking at each element step for a number of subsequent successive elements; and determining a display of the user's visual field based on the positions of and / or the distance between the successive elements and the determined duration, the determined user saccade angle, and the determined user saccade distance.

[0010] Implementations of the invention may include one or more of the following: The method may further include displaying an instruction to the user to look at the displayed element if it is detected that the user's one or more eyes are not looking at the displayed element. The step of detecting whether the user's one or more eyes are looking at the element may include detecting whether the user's one or more eyes are fixated on the element. The step of detecting whether the user's one or more eyes are looking at the element may include detecting whether the user's one or more eyes have moved in a direction toward the element. The step of detecting whether the user's one or more eyes have moved in a direction toward the element may include detecting whether the user's one or more eyes have moved in a direction from a previous element to a subsequent element. The method may further include determining a type of eye movement detected as part or all of the eye movement. The method may further include excluding certain types of eye movement from the step of detecting whether the user's one or more eyes are looking at the element step.

[0011] Implementations of the invention may include one or more of the following: The method may further include dividing the test of the visual field over multiple user sessions. At least one of the user sessions may further include completing one or more steps of the method one or more times to perform a coarser assessment of the visual field, and performing at least one additional repeat step within a user session subsequent to the previous user session to perform a finer assessment of the visual field. Performing the coarser assessment may include determining a first intensity window defined by upper and lower intensity values ​​that specify the intensity values ​​that the user will and will not perceive, respectively, and performing the finer assessment includes determining a second intensity window narrower than the first intensity window. The coarser assessment and the finer assessment may be performed on a common portion of the user's visual field. Different user sessions may be used to test different portions of the user's visual field. The method may further include tracking the user's iris size while performing the test to identify changes in the distance of the user's eye relative to the touch screen user interface, and taking the changes in the user's distance into account when determining where static and flash elements should be displayed on the touch screen user interface. For a user wearing glasses, the method may further include capturing the user's iris size with and without the glasses to determine a ratio between the iris size with and without the glasses, and using the ratio as a calibration factor to identify changes in the distance of the user's eye relative to the touch screen user interface. The method may further include tracking the size of at least one additional facial feature of the user while performing the test, and using the tracked changes in iris size and the at least one additional facial feature to identify changes in the distance of the user's eye relative to the touch screen user interface.The method may further include tracking the size of at least one additional facial feature of the user while performing the test, and using the tracked changes in iris size and the at least one additional facial feature to identify changes in the distance of the user's eyes relative to the touch screen user interface. One additional facial feature includes interpupillary distance. The method may further include displaying a stationary element and a flashing element on the touch screen user interface while a background intensity on the touch screen user interface is established at or below a level required to minimize or eliminate the user's perception of ambient light reflected from the touch screen user interface. The method may further include sliding the stationary element to different positions while performing the test. The stationary element may include progress indicia that indicate to the user the amount of the test remaining and / or completed. The method may further include determining, for a given position in the user's field of view, minimum and maximum intensity levels visible to the user, and repeating at least some of the steps at the given position while displaying the stationary element at an intensity level intermediate between the maximum and minimum intensity levels. The intermediate intensity level may be selected to be closer to the minimum or maximum intensity level based at least in part on the user response time required to see the flash element.

[0012] In a related aspect, the invention is directed to a computer-readable medium including instructions for causing a computing environment to perform any of the above-described methods. Such instructions may be downloadable from an online resource.

[0013] Advantages of particular implementations of the present invention may include one or more of the following: Systems and methods according to the present principles provide a very inexpensive and convenient way to perform visual field tests, such as tests of peripheral vision, for the diagnosis of eye and vision diseases, including glaucoma. [Brief description of the drawings]

[0014] [Figure 1]FIG. 1 illustrates a touch screen computer implementing one embodiment of the system and method according to the present principles. [Diagram 2] FIG. 1 illustrates a touch screen computer implementing another embodiment of the system and method according to the present principles. [Diagram 3] 2 is a flow chart showing how the system of FIG. 1 may be used. [Figure 4] 3 is a flow chart showing how the system of FIG. 2 can be used. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Like numbers refer to like elements throughout and elements are not to scale unless otherwise noted.

[0016] As noted above, systems and methods according to the present principles may in one implementation use a touch screen based device, such as a tablet computer or other computer incorporating a touch screen, to perform tests and receive input / output, It will be appreciated that any such device may be used so long as a display, a means for user input, and a means for eye tracking are provided, and the display screen is large enough to effectively test the visual field.

[0017] Two embodiments are illustrated in the accompanying drawings, however, other embodiments are understood in view of the present teachings.

[0018] Referring initially to Figure 1, a tablet computer 10 is shown having a display screen 12. The tablet computer may be, for example, an iPad, Android or Windows tablet. As can be seen, a volume control 14 may be provided, as well as a power button 18 or 22, or both. A camera 16 may be provided, which may be used to receive a visual image of a user, and in some implementations, to perform eye tracking by visually tracking the position of the user's eyes, such as using an eye tracking device 17. A home button 24 may be provided to redirect the screen to a home page.

[0019] The display screen 12 may implement a user interface through which a user may view rendered items and interact with the test application 25, for example by touching a touch screen UI. It will be appreciated that the test application 25, as shown diagrammatically, may cause the rendering of static elements 23, flash elements 24, and other elements depending on the implementation, as well as receive user input, as may be detected and / or measured on the touch screen 12, for example.

[0020] For example, the patient may be guided with appropriate instructions on the user interface (touch screen 12) to view the various elements on the screen and to interact with the displayed elements. For example, as shown in the figure, a static element 23 is displayed on the screen. The static element 23 is displayed continuously. A flash element 24 may also be displayed on the screen, but this is only displayed intermittently, e.g. as a flash. The positions of the static and flash elements may vary, but typically the further away the flash element is from the static element the further the test will be viewed (from the field of view).

[0021] In one exemplary test, a user may be instructed to look at the static element 23 and then tap the screen 12 when the flash element 24 becomes visible. Other user indications of the viewer viewing the flash element may also be provided, including, for example, clicking a mouse or saying an audible word or phrase. The user's ability to see the flash element while fixating on the static element indicates how much peripheral vision the user has.

[0022] In advanced implementations, eye movement may be tracked, such as by camera 16 or other eye tracking devices and methods, and the system may wait for the eye to fixate on a stationary element before displaying or flashing any of the flash elements. Gaze tracking or eye tracking may detect a user's gaze fixation on a stationary element, and may further detect, measure, or calculate a user's gaze fixation on a flash element.

[0023] In this case, the fixation action does not necessarily mean that the eyes do not move at all, because when the device or head moves, the eyes usually move to compensate. Rather, "fixation" here may refer to the eyes not moving or performing a slight smooth tracking to compensate for the head / device movement. The system may then wait for the user to tap the screen to confirm that the user is ready to begin. When the test begins, the patient fixates on the stationary element. While the patient is "fixed" on the stationary element, the system presents flash elements 24 at various distances and angles from the stationary element 23 in the patient's peripheral vision.

[0024] When the flashing element appears, the system tests to determine if the patient taps the screen in response, and the test may also include considering how long it took to look at the flashing element and respond to it. If the patient looks away from the stationary element, for example in the case of a saccadic movement, the system may stop the test and ignore the tap on the screen. The patient may then be notified that they are looking away and requested to look again at the stationary element to continue the test. These and other instructions to the patient may be provided by text displayed on the screen or by audio indicators and / or notifications.

[0025] The still and flashing elements may be of variable color, brightness, contrast against the background, length of time, and / or size, and may be static in any of these parameters or variable in any of these parameters, for the purpose of testing different visual elements or to variously test or capture the patient's attention.

[0026] An exemplary method of testing is provided by the flow chart 20 of Figure 3. In a first step, the user taps the display to initiate the test (step 48). A stationary element may then be displayed (step 52). The system begins to detect whether the user has fixed on the stationary element, and if the system detects such a fixation, step 54 is complete and the flow proceeds to step 56. In step 56, a flash element is displayed. The position of the flash element as well as its duration may be programmed or selected in a random process by the system and method.

[0027] The system may then detect that the user has at least partially fixed on the flash element (step 58). This step may be performed in a variety of ways. For example, in one implementation, the system determines whether the user taps on the touch screen, and the tap is accepted as an indication that the user has seen the flash element. In another implementation, an eye-tracking device or other detector may be used to determine whether the user has fixed on the flash element. Other techniques will be appreciated. The system may then record the time between the display of the flash element and the detection of the user's fixation on the flash element (step 62). This step is optional, and this time may not be necessary in all evaluations. However, it is usually important to record whether the user has seen the flash element, as well as some indication of the geometric relationship between the stationary element and the flash element. In some cases, since peripheral vision may depend on the rotational state of the user's eyes, information regarding the rotational position of the user's eyes may also be recorded, which may be used in combination with the position of the stationary element and the position of the flash element, and whether the user has detected that he or she has seen the flash element, in a general evaluation of the user's peripheral vision.

[0028] In some cases, the time notation is simply used to determine whether the next element should be displayed, e.g., whether the user has not seen the flash element and therefore the test should continue after a predetermined period of time. In other cases, the time taken to see and respond may be used in the calculation of other aspects of the user's visual acuity and / or peripheral visual function, such as response time from a stationary element to a flash element or saccade time and direction. For example, a faster speed and / or more accurate saccade direction at which the user reacts may be taken as evidence of better detection of the flash element and therefore better peripheral vision.

[0029] As noted, the system may record the positions of the stationary and flashing elements (step 64), and finally, the system may use the recorded data to provide an assessment of peripheral vision (step 66). The system may then display the results (step 68). A decrease in the speed or accuracy of the results reflected in the assessment may be considered a reflection of a decrease in the function of visual acuity and / or peripheral visual function.

[0030] The system and method may provide an iterative process of making a rough assessment of the user's peripheral vision, for example using a pre-programmed set of flash elements, followed by a more detailed assessment. For example, the initial assessment may be the same for everyone, with the user viewing a pre-defined set of flash elements in a pre-defined set of locations for a pre-defined period of time. Depending on the results of this assessment, the system may branch out to performing other tasks as indicated by the results of the initial test, including modifying the test and re-running parts of the test based on the initial assessment and results (step 72). For example, the results of the first test may indicate that the user's peripheral vision is worse on the right side than on the left side. This may be confirmed in a second series of tests by further rendering the flash elements on the right and left sides of the screen and determining the patient's ability to see them.

[0031] Referring now to system 10' of Figure 2, a tablet computer is again used, but a different type of test is displayed. In this approach, instead of tapping the device when a new or flashing element appears, the patient is instructed and expected to change gaze and watch such flashing element appear in their peripheral vision. In Figure 2, the first element in the sequence is shown as element 32, the second element in the sequence is shown as element 34, followed by the third element as element 36. Note that these flashing elements are displayed in sequence.

[0032] Using an eye-tracking device, or possibly (or instead) using the user tapping on the touch screen 12, the system times the look response to the appearance of the new element to assess whether the patient actually saw the new element and responded to its appearance. For this reason, eye-tracking can be particularly useful in this implementation. In particular, the system does not need to measure whether the user saw the new flashing element exactly, but rather whether the user responded to its appearance by looking in its direction. Important variables measured include time, and timing factors can also be used to determine how long it took the user to respond, as well as characteristics of eye movement saccades, including speed, direction or vector.

[0033] The stationary and flashing elements may be of variable color, brightness, contrast against the background, length of time, and / or size, and may be static in any of these parameters, or variable in any of these parameters, with the goal of testing different visual elements or variously testing or capturing the patient's attention. In an alternative but related implementation, the patient may be guided to always return to the same "origin" fixed point each time, or, as noted, the test can move from point to point, varying brightness or size, and the visual field (see FIG. 2) calculated across this constantly moving format.

[0034] The calculations involved in evaluating the results and determining the quality of peripheral vision, or an increase or decrease in the quality of peripheral vision if determined multiple times with time intervals, include whether a saccade to the next point occurs, measured as "yes" or "no," where "yes" has some limitations, such as, for example, that this must occur within 1 second, ideally within 500 milliseconds, of the appearance of the next point, and that this must demonstrate a saccade in the direction of the next point, measured as a deviation that must be within 30 degrees, ideally within 5 degrees, of the direction of the next point, and that this must reach the distance of the next point, possibly within a predetermined time period, usually within plus or minus 25% of the total distance, ideally within 10% of the total distance. Measurements also include if there is a refixation movement or additional saccade to complete fixation on the next spot. In addition to summing these measurements as "yes" or "no" for each spot, the raw measurements can be used to assess the quality of vision in each direction from fixation, such that measurements of shorter time (e.g., closer to 200 milliseconds), closer saccade direction (e.g., closer to 0 degrees deviation), and closer distance (e.g., accurate at full distance), as well as the number of additional refixation movements or saccades required (e.g., 0 additional saccades required) are indicators of better visual function in that region of peripheral vision.

[0035] FIG. 4 shows a flow chart 30 that may be implemented by the system of FIG. 2. As before, the user may tap the display to initiate a test (step 49). However, in this case, a first element is displayed (step 51). Unlike the method of FIG. 3, the first element may be made to disappear upon display or rendering of the second element. However, prior to this, the system detects that the user is fixating or otherwise gazing at the first element (step 53). Subsequently, the first element is removed and the second element is displayed (step 55). As before, the system may detect that the user has at least partially moved their gaze towards the second element (step 57). The system may record the detection of the gaze (step 59), e.g., the time from when the gaze is detected at the first element to when the gaze is detected at the second element. The system records the direction and distance of the saccade towards the second element. These steps may be repeated for the third, fourth, fifth, etc. elements. The system records the location of the element (step 61) and whether the user was able to detect the field of view of the element in the peripheral vision. The system records the direction and distance of the saccade toward the subsequent element. The system may then use the recorded data to evaluate the user's peripheral vision (step 63). The system may then display the results (step 65). As mentioned above, depending on the results of the previous test, pre-programmed tests may be modified and re-run based on the initial evaluation and results (step 67).

[0036] Typically in each of these embodiments, single flash elements are displayed sequentially, although in alternative implementations the single flash elements may be separated by fixed time intervals, the single flash elements may appear for different amounts of time, and in some cases more than one flash element may be displayed at once.

[0037] In one implementation, details of how eye movements can be analyzed and tracked include those disclosed in U.S. Patent Application entitled "SYSTEM AND METHOD FOR ANALYSIS OF EYE MOVEMENTS USING TWO-DIMENSIONAL IMAGES" and patent applications incorporated by reference therein, all of which are incorporated by reference herein. Other implementations may be understood. Typically, eye trackers that measure eye position or point of gaze may be used. In an exemplary implementation, a video-based eye tracker may be used in which a camera focuses on one or both eyes and records their movements. Such may include infrared or near-infrared eye tracking technology.

[0038] The systems and techniques described above are designed to allow patients to test their visual field themselves on a general-purpose consumer device, such as a tablet computer. Unlike tests performed in the controlled environment of a doctor's office on equipment designed and dedicated to performing such tests, performing visual field tests on consumer devices and performing such tests by patients presents several challenges. To address some of these challenges, several examples of techniques that may be used in combination with the systems and techniques described in the aforementioned references are presented below. These techniques may be used individually or in any suitable combination as an adjunct to the systems and techniques described herein.

[0039] EMBODIMENT 1 A primary objective of this embodiment is to achieve large visual field testing on a small screen that may not have a large enough area to test the patient's entire peripheral vision, which may be difficult to achieve if, for example, a first fixation element of any of the tests described above is displayed in the center of the screen with a second element displayed around it, as this limits the maximum possible distance between the two elements, thereby limiting how much of the patient's peripheral vision can be tested.

[0040] To address this issue, instead of using a stationary fixation element to test multiple locations on the retina, the fixation element is periodically moved to test different locations. For example, if the fixation element is to the left edge of the screen, then essentially the full width of the screen is made available to test the visual field to the right of the screen. Similarly, if the fixation element is moved to the bottom edge of the screen, then the full height of the screen is available to test the visual field.

[0041] In some cases, the test will normally move the fixation element to a new position after testing a specific location on the retina, so in these cases the test will naturally already move the fixation element to allow the user room to see elements in new positions that were previously out of range. However, this may not be enough to test all positions in the visual field, especially since the user may miss some elements due to visual field defects. Thus, to test the full angular range of the user's peripheral vision, the fixation element may be periodically moved to a new position on the screen to ensure that all visual field positions are tested and are not out of range. Importantly, the fixation element movement may be a jump, but more preferably, the fixation element slides, which is consistent with inducing smooth tracking on the part of the user and ensures that the fixation element movement is not missed by the user. In some cases, an algorithm may be used that governs which points are presented and ensures that the largest possible visual field is tested by a mixture of jumping and sliding of the fixation element, even if the screen on which the test is presented is relatively small.

[0042] EMBODIMENT 2 The primary objective of this embodiment is to achieve a comprehensive yet relatively short test that can test many different intensity levels, but also achieves a high degree of discrimination between the different intensity levels. This can be difficult to achieve because the test requires measuring different levels of intensity at many different locations in the field of view, which can result in a lengthy test if all desired locations and intensity levels are tested. This can cause fatigue to the user and reduce the accuracy of the test.

[0043] To address this issue, instead of performing a single, comprehensive test in a single session, the test may be split up to be performed over multiple sessions. In some embodiments, instead of randomly terminating the sub-tests performed in a single session at any point (e.g., after a predetermined time has elapsed), each sub-test may be performed in a manner that provides useful information, e.g., allowing subsequent sub-tests to further refine previously obtained results.

[0044] For example, in some cases, an initial sub-test may be performed to roughly test the visual field at different intensity levels and different locations within the visual field, with subsequent sub-tests being performed to more precisely determine the intensity levels that the user can see. For example, if an initial test determines that the user can see a displayed element having an intensity level of 100 (arbitrary units) at a particular location, but cannot see an intensity level of 50, a subsequent test may be performed to determine whether the user can see an intensity level of, say, 75. If so, a subsequent sub-test may be performed at that location to more precisely determine the intensity level between 50 and 75 at which the displayed element is no longer visible to the user. Alternatively or additionally, an initial test may roughly define locations on the retina where the user may have a visual defect, and subsequent sub-tests may be performed to more precisely identify the boundary between areas where a visual defect is present and areas where it is not. For example, one sub-test may broadly test various areas of the visual field, and subsequent tests may be satisfied by testing previously untested locations or by focusing on specific areas identified as more likely to produce defects. In other words, in some embodiments, each subsequent sub-test may iteratively refine the results obtained in the previous sub-test to improve the resolution and precision of the ultimately obtained data.

[0045] EMBODIMENT 3 The main purpose of this embodiment is to allow the user to sit freely without having to keep their head in a fixed position at a certain distance relative to the screen while performing the test. This can be difficult to achieve since the test focuses on testing the user's ability to see displayed elements that are in the periphery of the user's visual field. The position of the displayed element on the screen is defined by an angle. The point on the screen at which the fixation element is presented depends on the distance between the user's iris and the screen. If this distance varies from test to test, or even within a test, a displayed element that is presented at a certain pixel distance from the fixation element on the screen will actually appear in a different position on the user's retina, thus testing different and unexpected angles in the visual field.

[0046] To address this issue, the size of the iris may be tracked, which has an average diameter of 1.18 cm, and has the only minimal deviation between people, regardless of age, beyond about 1 year, since it is the only facial feature that is fairly consistent between people. Thus, the iris can be used to calculate the absolute distance to the screen, possibly along with measured changes in size of other facial features. In this way, the distance of the user's iris to the screen can be determined and monitored to identify changes in the distance of the user's iris to the screen. Before presenting a displayed element on the screen, this distance is calculated, and then the pixel distance on the screen required to present the displayed element at a particular visual angle on the screen is calculated. In this way, the position of the displayed element on the screen is constantly adapted based on the user's distance to the screen. In some embodiments, the size of the displayed element may also be changed based on the user's iris distance to the screen. In other embodiments, the visual field angle calculation changes when assembling the data for the entire visual field test. One example of a method for determining the distance between a user's iris and the screen may be found in U.S. Pat. No. 10,254,831, which is incorporated herein by reference in its entirety.

[0047] EMBODIMENT 4 The main purpose of this embodiment is to measure the distance of the user's iris relative to the screen even while wearing glasses. As explained above, the size of the iris may be used to estimate the user's distance from the screen, which is then used to determine the distance at which displayed elements should be presented on the screen to correspond to a known viewing angle and therefore viewing position. If the size of the iris detected by the camera is affected by the myopic or hyperopic glasses worn by the user, this may result in an incorrect calculation of the distance of the user's iris relative to the screen, making the user appear closer or further from the screen than they actually are.

[0048] To address this issue, the camera captures an image of the iris while the user is wearing the glasses before starting the test for the first time, so that the system can calculate the user's iris size. In some embodiments, this is compared to other facial features and distances that do not change whether the glasses are worn or not. The system then asks the user to remove the glasses while the camera captures an image of the iris again, so that the system can calculate the user's iris size again. The two iris sizes are compared, and their ratio can be used as a calibration factor throughout the test to compensate for the change in size due to the glasses.

[0049] In some embodiments, comparison with other facial feature sizes and distances is used to normalize the iris size calculation if the patient changes their distance from the camera while adding or removing glasses. In this way, the iris size used to calculate the distance between the user and the screen is used to convert the viewing angle to a position on the screen throughout the test, and this can be calibrated to match that of the distance calculation if the user's iris size was captured without glasses. In some cases, the measurement may only be performed once, and the same calibration may be used throughout that test and possibly subsequent tests. In other cases, the user may be prompted to periodically recalculate the calibration factor, since the user may wear glasses differently or may wear different glasses, which may affect the apparent size of the iris.

[0050] In one example of the embodiment described above where other facial sizes or distances are tested in addition to or instead of measuring iris size with and without glasses, the camera may capture the interpupillary distance, which is less affected by glasses than iris size. In some embodiments, the interpupillary distance may be measured and used to compensate for changes in distance that may occur between the time the user's iris is measured with and without glasses. In some cases, a doctor or other practitioner may input a known interpupillary distance into the system so that the system does not need to measure the user's iris size. Rather, the interpupillary distance is captured on the screen, measured in pixels, and compared to the known interpupillary distance to obtain a ratio, and then the pixel iris diameter is measured and compared to the average 1.18 cm diameter to obtain that ratio. The two ratios are then compared, and without glasses, they are the same, so by comparing the difference between the ratios, the effect of glasses on the measurement is determined. In this way, knowing the pixel interpupillary distance can replace the step of removing the glasses.

[0051] As another example, the distance and size of the head, nose, mouth, chin, ears, or other features can be measured collectively and used accordingly, thus ensuring that only changes in apparent iris size caused by glasses are captured, and not changes in apparent iris size caused by changes in the user's position.

[0052] EMBODIMENT 5 The main purpose of this embodiment is to avoid unbalanced reflections from light sources in the room away from the screen, which can make certain parts of the screen less visible than others. When displayed elements are presented on the screen at variable intensity levels, the minimum level presented cannot be below the intensity of the background. For example, if the background is black, the reflections observed on the screen may prevent different areas of the screen from presenting light at lower intensity levels. On the other hand, if the entire screen is very bright, fewer reflections are observed, but the ability to display a wide range of contrast between the bright background and the stimuli is more limited. Furthermore, a bright screen may create reflections from the user's glasses that can prevent them from seeing the camera eye.

[0053] Typically, the darker the screen, the more reflections from the room are visible. On the other hand, bright lights can both minimize the intensity range available for testing and create reflections on the user's glasses, which can negatively affect eye tracking and the user's ability to see the screen clearly. To address this issue, the screen may be set to an intermediate intensity level (e.g., gray) that projects enough light to minimize the user's perception of light reflecting off the screen, but is not so bright as to limit the range of contrast of the stimuli compared to the background from testing or to create reflections on the user's glasses.

[0054] It should be noted that reflections from a screen typically arise from a particular light source in the room shining on the screen, not from the overall light level in the room. Thus, in some embodiments, the system's camera may detect areas of relatively high intensity light being projected toward the screen and, in response, present an on-screen prompt asking the user to take corrective action to reduce that light. Additionally (or alternatively), in some cases, the user may be prompted to adjust the overall background light level in the room based on a measurement of the overall ambient light level in the room.

[0055] EMBODIMENT 6 A primary goal of this embodiment is to keep the user engaged and prevent the user's eyes from "wandering" as a result of fatigue or frustration, which can be problematic in traditional visual field testing because the user's eyes are fixed in one position for the duration of the test, which can be tiring.

[0056] To address this issue, in contrast to traditional visual field testing, in some embodiments, the systems described herein may move (e.g., slide) the fixation element during the test in order to keep the user more focused and engaged. This may be even more difficult if the user is focused on the same screen location for too long, as the user may anticipate the next movement and begin to wander in search of a new fixation element. That is, if the user is fixed on the same location for, e.g., more than a few seconds, missing a displayed element, or wandering and lack of focus, the fixation element may be moved to a new location (e.g., slid to induce smooth tracking that does not rely on functional peripheral vision) and the test may continue from there. Moving the fixation element may give the user a sense of progression, reduce frustration, and keep the user engaged and focused. Furthermore, moving the fixation element in this way may prevent local screen defects (e.g., screen dirt, smudges, defective pixels, reflections) from obtaining erroneous measurements when these defects prevent the user from seeing the displayed element, because with each new fixation location, the viewing angle surrounding that central fixation point is redistributed to different locations on the screen. One advantage of sliding the fixed point by simply jumping to a new position is that when sliding, the user's eyes slide naturally without losing contact with the fixed point ("smooth tracking").

[0057] EMBODIMENT 7 The main purpose of this embodiment is to allow the user to know how they are progressing and understand how much of the test is left. Because the test is based on the user looking at a fixed element, and in some embodiments also looking towards a peripheral element in response, it is preferable not to have additional information on the screen that may distract the user and make them look at it. Therefore, it may be difficult to let the user know how much progress they are making in the test.

[0058] In some embodiments, the fixed element itself may provide an indication of progress. For example, a progress bar, a pie chart with a filled portion displaying the percentage of tests completed, or some other feature may be incorporated into the fixed element to indicate the amount of tests completed and / or remaining. It is also contemplated as part of the present invention that variables within the fixed element may aid in the user's engagement throughout the duration of a test.

[0059] EMBODIMENT 8 The main objective of this embodiment is to quickly find a threshold intensity at each location in the user's field of view that stops the user from seeing the displayed element. This can be problematic because there are many locations in the user's field of view to test and it is desired to find the exact threshold intensity at which the user can see at each location. If all locations are tested at many intensity levels, it will take a very long time. In some embodiments, when frequent tests are performed, one would like to shorten the test by using previously acquired test data, but this presents a problem because one needs to ensure that the data is still relevant and has not been changed.

[0060] To address this issue, an algorithm can be used that defines visible and invisible intensity values ​​("V" and "NV"). Visible is the highest test value that the user can see, and invisible is the lowest intensity value that the user can see. At each iteration of the algorithm, the system presents a midpoint ("M") value between V and NV. If M values ​​are seen, then V=M, and if M values ​​are not seen, then NV=M. At the next iteration, M is halfway between the new values ​​of V and NV, and so on. In this way, the test can very quickly slide through the range between V and NV, thereby converging on a threshold intensity value. In some embodiments, instead of simply assuming that the threshold is halfway between V and NV, the threshold can be assumed to be closer to V or closer to NV, based in part on the user's response time required to see the displayed element. For example, if V=100 and NV is 50, and the user responded very quickly to 100, then the user's threshold can be estimated to be closer to 50 than 100. On the other hand, if the user saw 100 but responded slowly to it, then the threshold is more likely to be closer to 100 than 50.

[0061] In some embodiments, if there are V and NV intensity values ​​available from a previous test, they can be used as a starting point, but they can be designated as "unverified". What this means is that the test will not end unless a new V and NV are generated or the same "unverified" values ​​are retested. For example, if the previous test had V=200 and NV=100, these values ​​can be used as a starting point, but are defined as "invalid". In the first iteration, the M value may be, for example, 150. If the user sees it, V=150. If the test ends here, NV=100, but since it has been designated as "unverified", the system will retest with 100 before ending the test to ensure that it is not actually seen before verifying. This ensures that the test uses previous data to better infer the intensity range to be tested without assuming that the previous data is still valid. Note that in some cases, previously obtained NV and V values ​​designated as "unverified" may be associated with an expiration date. For example, if the previous test was performed yesterday and has not passed the expiration date, the NV and V values ​​can be assumed to still be valid, but if the previous test was performed a month ago and has passed the expiration date, the NV and V values ​​can be designated as "unverified" and therefore require additional validation as described in the algorithm above.

[0062] Note that each location in the peripheral vision that is tested has a V and NV value associated with it. However, in some embodiments, the algorithm may use the V and NV values ​​of adjacent locations, or an average of neighboring locations, to estimate the intensity range to be tested. Finally, note that in some cases, the user may not be able to see any displayed elements at a particular location, so in this case NV=maximum intensity and V is not relevant.

[0063] Various embodiments of the systems and methods described above may be fully implemented within any number of computing devices. Typically, instructions are located on a computer-readable medium, usually non-transitory, and these instructions are sufficient to enable a processor within the computing device to implement the methods of the present invention. The computer-readable medium may be a hard drive or solid-state storage with instructions loaded into a random access memory at execution time. For example, input to the application from multiple users or any one user may be by any number of suitable computer input devices. For example, a user may use a keyboard, mouse, touch screen, joystick, trackpad, other pointing device, or any other such computer input device to input data related to the calculation. Data may also be input via an inserted memory chip, hard drive, flash drive, flash memory, optical media, magnetic media, or any other type of file storage medium. Output may be delivered to the user via a video graphics card or integrated graphics chipset coupled to a display that the user can view. Alternatively, a printer may be used to output a hard copy of the results. Given this teaching, it is understood that any number of other tangible outputs are also contemplated by the present invention. For example, the output may be stored on a memory chip, a hard drive, a flash drive, flash memory, optical media, magnetic media, or any other type of output. It should also be noted that the present invention may be implemented in any number of different types of computing devices, such as personal computers, laptop computers, notebook computers, netbook computers, handheld computers, personal digital assistants, mobile phones, smartphones, tablet computers, and devices designed specifically for these purposes. In one implementation, a user of a smartphone or WiFi connected device downloads a copy of the application from a server to their device using a wireless Internet connection.Appropriate authentication procedures and secure transaction processes may be provided for payments to be made to the merchant. The application may be downloaded via a mobile connection or via a WiFi or other wireless network connection. The application may then be executed by the user. Such a networked system may provide a suitable computing environment for implementations in which multiple users provide separate inputs to the systems and methods. In the following systems in which visual field testing is contemplated, multiple inputs may allow multiple users to simultaneously enter relevant data. [Explanation of symbols]

[0064] 10 tablet computer, 10' system, 12 touch screen, display screen, 14 volume control, 16 camera, 17 eye tracking device, 18 power button, 20 flow chart, 23 still element, 24 home button, flash element, 25 test application, 30 flow chart, 32 first element in sequence, 34 second element in sequence, 36 third element in sequence

Claims

1. 1. A method for testing a user's visual field, comprising: a. displaying a static element on a touch screen user interface; b. detecting whether one or more eyes of a user are fixed on said stationary element; c. if one or more eyes of the user are not fixed on the stationary element, displaying instructions to the user to look at the stationary element; d. displaying a flash element at a first location within peripheral vision at a first given time if and for the duration that one or more eyes of the user are fixated on the stationary element; e. receiving a signal indicating that a user saw the flash element while one or more eyes of the user were fixed on the stationary element; f. repeating the steps of displaying a flash element at the first location or another location within the peripheral vision and receiving a signal for one or more subsequent given periods of time; g. determining a representation of the field of view of the user based on the received signals; h. repeating steps a-f one or more times while displaying the stationary element at different locations on the touch screen user interface, thereby enhancing the amount of peripheral vision being tested; A method comprising:

2. The method of claim 1 , wherein at least one of steps a-f is repeated while displaying the stationary element on an edge of the touch screen user interface.

3. 2. The method of claim 1, wherein the step of repeating steps a-f one or more times while displaying the stationary element at different locations on the touch screen user interface is performed a sufficient number of times to test all locations within the user's peripheral vision.

4. 2. The method of claim 1, wherein the step of repeating steps a-f one or more times while displaying the stationary element at different positions on the touch screen user interface comprises sliding the stationary element to the different positions.

5. The method of claim 1 , further comprising dividing the testing of the visual field across multiple user sessions.

6. 6. The method of claim 5, further comprising: during at least one of the user sessions completing steps a-f one or more times to perform a coarser assessment of the visual field; and performing steps a-f at least one additional time within a user session subsequent to at least one of the user sessions to perform a finer assessment of the visual field.

7. 7. The method of claim 6, wherein performing the coarser assessment includes determining a first intensity window defined by upper and lower intensity values ​​that specify intensity values ​​that the user will and will not perceive, respectively, and performing the finer assessment includes determining a second intensity window narrower than the first intensity window.

8. The method of claim 7 , wherein the coarser assessment and the finer assessment are performed for a common portion of the field of view of the user.

9. The method of claim 5 , wherein different user sessions are used to test different portions of the field of view of the user.

10. 10. The method of claim 1, further comprising: tracking an iris size of the user while performing the test to identify changes in a distance of the user's eyes relative to the touch screen user interface; and taking the changes in distance of the user into account when determining where the static and flash elements should be displayed on the touch screen user interface.

11. For users who wear glasses, capturing an iris size of the user with and without the eyeglasses to determine a ratio between the iris sizes with and without the eyeglasses; using the ratio as a calibration factor to determine a change in the distance of the user's eyes relative to the touch screen user interface; The method of claim 10 further comprising:

12. 11. The method of claim 10, further comprising: tracking a size of at least one additional facial feature of the user while performing the test; and using the tracked changes in iris size and the at least one additional facial feature to identify the change in the distance of the user's eyes relative to the touch screen user interface.

13. 12. The method of claim 11, further comprising: tracking a size of at least one additional facial feature of the user while performing the test; and using the tracked changes in iris size and the at least one additional facial feature to identify the change in the distance of the user's eyes relative to the touch screen user interface.

14. The method of claim 13 , wherein one of the additional facial features includes interpupillary distance.

15. 10. The method of claim 1, further comprising the step of displaying the still and flashing elements on the touch screen user interface while a background intensity on the touch screen user interface is established at or below a level required to minimize or eliminate a user's perception of ambient light reflected from the touch screen user interface.

16. The method of claim 1 , further comprising the step of sliding the stationary element to different positions while performing the test.

17. 2. The method of claim 1, wherein the step of repeating steps a-f one or more times while displaying the stationary element at different positions on the touch screen user interface comprises sliding the stationary element to the different positions.

18. The method of claim 1 , wherein the fixation element includes progress indicia that indicate to the user the amount of the test remaining and / or completed.

19. 2. The method of claim 1, further comprising the steps of: determining, for a given position within the field of view of the user, minimum and maximum intensity levels visible to the user; and repeating steps a-f at the given position while displaying the stationary element having an intermediate intensity level between the maximum and minimum intensity levels.

20. 20. The method of claim 19, wherein the intermediate intensity level is selected to be closer to the minimum or maximum intensity level based at least in part on a response time of the user required to see the flash element.

21. A computer readable medium comprising instructions for causing a computing environment to perform the method of claim 1.

22. 22. The medium of claim 21, wherein the instructions are downloadable from an online resource.

23. 1. A method for testing a user's visual field, comprising: a. detecting a user input indicating that visual field testing should begin; b. displaying the first element on a touch screen user interface; c. detecting whether one or more eyes of a user are looking at the first element and determining a first duration between the display of the first element and the detecting step; d. repeating the steps of displaying and detecting whether the user's eyes are looking at each of the element steps for a plurality of subsequent successive elements; e. determining a representation of the user's field of view based on the positions of and / or the distances between the successive elements and the determined duration, the determined user saccade angle, and the determined user saccade distance; f. tracking the user's iris size while performing said test to identify changes in the distance of the user's eyes relative to said touch screen user interface and taking said changes in distance of the user into account when determining where on said touch screen user interface said static and flash elements should be displayed; A method comprising:

24. For users who wear glasses, capturing an iris size of the user with and without the eyeglasses to determine a ratio between the iris sizes with and without the eyeglasses; using the ratio as a calibration factor to determine a change in the distance of the user's eyes relative to the touch screen user interface; 24. The method of claim 23, further comprising:

25. 24. The method of claim 23, further comprising: tracking a size of at least one additional facial feature of the user while performing the test; and using the tracked changes in iris size and the at least one additional facial feature to identify the change in the distance of the user's eyes relative to the touch screen user interface.

26. 25. The method of claim 24, further comprising: tracking a size of at least one additional facial feature of the user while performing the test; and using the tracked changes in iris size and the at least one additional facial feature to identify the change in the distance of the user's eyes relative to the touch screen user interface.

27. 27. The method of claim 26, wherein one of the additional facial features includes interpupillary distance.

28. 24. The method of claim 23, further comprising the step of displaying the still and flashing elements on the touch screen user interface while a background intensity on the touch screen user interface is established at or below a level required to minimize or eliminate a user's perception of ambient light reflected from the touch screen user interface.

29. 24. The method of claim 23, further comprising the step of sliding the stationary element to different positions while performing the test.

30. 24. The method of claim 23, wherein the step of repeating steps a-f one or more times while displaying the stationary element at different positions on the touch screen user interface comprises sliding the stationary element to the different positions.

31. 24. The method of claim 23, wherein the fixation element includes progress indicia that indicate to the user the amount of the test remaining and / or completed.

32. 24. The method of claim 23, further comprising determining, for a given position within the field of view of the user, minimum and maximum intensity levels visible to the user, and repeating steps a-f at the given position while displaying the stationary element having an intermediate intensity level between the maximum and minimum intensity levels.

33. 33. The method of claim 32, wherein the intermediate intensity level is selected to be closer to the minimum or maximum intensity level based at least in part on a response time of the user required to see the flash element.

34. 24. A computer readable medium comprising instructions for causing a computing environment to perform the method of claim 23.

35. 35. The medium of claim 34, wherein the instructions are downloadable from an online resource.

36. 24. The method of claim 23, further comprising repeating steps a-d one or more times while displaying the first element at different locations on the touch screen user interface, thereby enhancing the amount of peripheral vision tested.

37. 37. The method of claim 36, wherein at least one of steps a-d is repeated while displaying the first element on an edge of the touch screen user interface.

38. 37. The method of claim 36, wherein the step of repeating steps a-d one or more times while displaying the first element at different locations on the touch screen user interface is performed a sufficient number of times to test all locations within the user's peripheral vision.

39. 2. The method of claim 1, wherein the step of repeating steps a-f one or more times while displaying the stationary element at different positions on the touch screen user interface comprises sliding the stationary element to the different positions.

40. 24. The method of claim 23, further comprising dividing the testing of the visual field across multiple user sessions.

41. 41. The method of claim 40, further comprising: at least one of the user sessions completing steps a-d one or more times to perform a coarser assessment of the visual field; and performing steps a-f at least one additional time in a user session subsequent to at least one of the user sessions to perform a finer assessment of the visual field.

42. 42. The method of claim 41 , wherein performing the coarser assessment includes determining a first intensity window defined by upper and lower intensity values ​​that specify intensity values ​​that the user will and will not perceive, respectively, and performing the finer assessment includes determining a second intensity window narrower than the first intensity window.

43. 43. The method of claim 42, wherein the coarser assessment and the finer assessment are performed for a common portion of the field of view of the user.

44. 41. The method of claim 40, wherein different user sessions are used to test different portions of the field of view of the user.

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