Eye movement measurement device with 2D display projector and retroreflective screen

Abstract

An eye movement measurement device including a projection device, the projection device including a micro LED display device with an array of light-emitting pixels and an optical lens disposed in optical communication with the micro LED display device, the optical lens configured to project light into a field of view of the optical lens. The device further includes a retroreflective screen disposed to overlap the field of view of the optical lens. The projection device can be disposed near one or more patient's eyes, and the retroreflective screen can retroreflect light toward the one or more patient's eyes.

Description

[Technical Field]

[0001] The present invention relates to systems and methods for oculometry testing, including videonystagmography (VNG). [Background technology]

[0002] Conventional eye movement measurement devices have several drawbacks. One issue is the mechanical mobility of the laser-driven eye motor required for laser-based solutions, which can cause long-term reliability issues. There is a need in the art for a solution that achieves the same functionality in terms of effectively illuminating a stationary stimulus spot or moving a stimulus spot on a screen in both horizontal and vertical directions using only solid-state components.

[0003] Another problem in the prior art is the need for a separate, stationary laser in conventional VNG goggle solutions. Such solutions limit the use of retroreflective screens, thereby increasing the brightness of the light required to perform oculometry testing. There is a need in the art for a solution that is sufficiently lightweight and compact to be placed within a goggle device.

[0004] Another problem with the prior art is that the eye motors cannot be driven at the speeds required to generate raster-scanned animation in real time, and so are limited to a single stimulation point by using a single scanning laser beam with limited movement speed. There is a need in the art for a solution to generate real-time 2D patterns in the form of animations / movies that can be generated to enable additional balance-related tests, such as optokinetic testing, that cannot be provided by conventional eye-motor-based laser spot solutions and therefore require a separate display screen.

[0005] Another problem in the prior art is the size and weight of the eye motor subassembly, as the overall weight and size of a goggle-based eye movement measurement solution are important factors in usability. Conventional solutions are excessively large and heavy, hindering usability. There is a need in the art for a lighter, more compact eye movement measurement solution that is easily placed within goggles, preferably of small size and comfortable weight, to improve usability, particularly compared to the eye motor subassembly.

[0006] Another problem with the prior art relates to the relative complexity of the mechanical design of the eye motor subassembly and the difficulties associated with manufacturability, compared to extremely simple modular designs that can be manufactured separately and easily integrated into eye movement measurement goggles. Current eye motors are two-axis stepper motors coupled with bevel gear systems to drive lasers to point in both the x and y directions. To avoid or significantly reduce the mechanical coupling between the x and y motions, current designs are increasingly complex, incorporating ball bearings, high-precision bevel gears, and precise adjustment of the relative positions of the two bevel gears using shims. The two-axis motor is mounted directly to the PCBA board, which creates manufacturing challenges and lacks modularity. There is a need for a subassembly that can be manufactured separately from the goggle housing, independently tested for quality control, and then easily integrated into a goggle eye movement measurement device.

[0007] Another problem in the prior art relates to the cost of the eye motor subassembly. With augmented reality (AR) and virtual reality (VR) goggles in significant ongoing development, self-emissive microdisplays with improved cost, size, and display brightness are becoming commercially available. Therefore, a solution utilizing such devices would be advantageous.

[0008] Another problem in the art relates to power consumption and, therefore, the brightness of the stimulus or video scene on the viewing surface. Many eye movement measurement devices are power-limited because they are designed to be powered by USB 3.0 cables, which have limited power supply. Therefore, when the power provided by the USB cable is converted to light output, the light output is also limited. As a result, when using a 2D display projector, the brightness of the display on a screen or wall approximately 1.5 to 2 meters away is typically limited to a level that is not clearly visible to the patient in a room with room lights on. This is particularly true when a short-throw optical projector is required, such as in the case of VNG goggles, which require a viewing angle of at least ±30 degrees horizontally and ±25 degrees vertically. Therefore, a solution is needed that utilizes a retroreflective screen, which redirects light rays striking the screen primarily along or around its incident path. By placing the light exit port of the two-dimensional display optical projector somewhere between the patient's eyes based on a particular design, more light energy can be directed from the retro-reflective screen to the patient's eyes compared to the light energy at the wall where the incident beam is scattered / reflected uncontrollably and a much lower percentage of light returns to the patient's eyes.

[0009] Another problem in the prior art relates to the projection field of view (FOV). Current solutions either have optically excessive sizes and short throw ratios, or projectors with limited FOVs that are insufficient for eye movement measurement, specifically videonystagmography (VNG), applications when the projector is compact enough to be integrated into eye movement measurement goggles. There is a need in the art for an eye movement measurement solution with a wide-angle projection lens that can be universally used in wide-angle imaging applications. For VNG stimulus projection applications, the projected stimulus spot does not need to have a strictly dimensionally controlled size across the entire FOV region. As long as the opposing angular range of the stimulus spots is less than 1 degree as defined in the S3.45-2009_R2019 standard, optical magnification differences can cause stimulus spot size differences that are sufficiently controllable to meet the 1-degree opposing angular range requirement. Optical distortion can be calibrated, allowing corresponding pixels or binned groups of pixels to be turned on for specific angles or stimulus spot positions. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a perspective view of an eye movement measuring device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram of the eye movement measuring device of FIG. 1. [Figure 3] 2 is a representative diagram of a pixel array of a display device of a projection device according to one embodiment of the present invention. [Figure 4] FIG. 2 is a perspective view of a goggle device of the eye movement measuring device of FIG. 1. [Figure 5] 1 is a flow chart illustrating a method for conducting an eye movement measurement test according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention will now be described more fully hereinafter with reference to the accompanying drawings, which show preferred embodiments of the invention. However, the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Those skilled in the art will understand that the following description of embodiments of the invention is illustrative and not intended to be in any way limiting. Other embodiments of the present invention will be readily suggested to such skilled artisans having the benefit of this disclosure. Like numbers refer to like elements throughout.

[0012] Although the following detailed description contains many specifics for purposes of illustration, those skilled in the art will appreciate that many variations and modifications to the following specifics are within the scope of the present invention. Accordingly, the following embodiments of the present invention are described without any loss of generality to, and without imposing limitations on, the invention.

[0013] In describing the present invention in detail, those skilled in the art should note that directional terms such as "upper," "lower," "top," "bottom," and other similar terms are used for the convenience of the reader referring to the drawings. Those skilled in the art should also note that other terms may be included herein to convey position, orientation, and direction without departing from the principles of the present invention.

[0014] Furthermore, those skilled in the art should note that in this detailed description, quantitative modifiers such as "generally," "substantially," "mostly," and other terms are generally used to mean that the object, characteristic, or quality in question constitutes the majority of the referenced object. The meaning of any of these terms depends on the context in which it is used, and that meaning may be expressly modified.

[0015] As shown and described in the various figures and accompanying text, one embodiment of the present invention provides an eye movement measurement device that can be used to perform videonystagmus testing. Referring now to FIG. 1 , an apparatus 100 according to one embodiment of the present invention is presented. The apparatus 100 may include a goggle device 102 and a retroreflective screen 120. The goggle device 102 may be configured to be worn by a patient. The goggle device 102 may include a projection device 110, as shown in FIG. 2 . The projection device 110 is operable to emit light onto the retroreflective screen 120. The retroreflective screen 120 is configured to elicit a biological response, such as nystagmus, in a patient viewing the retroreflective screen 120 for vestibular function assessment. The unique reflective properties of the retroreflective screen 120, which reflects projected light back toward the direction from which it was projected, result in a significantly lower required intensity of light emitted by the projection device compared to standard screens that reflect projected light more diffusely or only toward the projection direction at very small or zero angles of incidence. This may facilitate smaller, lighter weight display devices that may be placed in a wider variety of locations, including, as shown in this embodiment, within goggle device 102. It is envisioned and within the scope of the present invention that the display device may be placed in other locations, including, but not limited to, on headgear attached to or positioned adjacent to the patient's head, on a surface adjacent to the patient's head, etc.

[0016] Projection device 110 may include a display device 112. Display device 112 may be operable to emit light in a grid configuration. In some embodiments, display device 112 may be a micro-LED display device comprising an array of light-emitting pixels. Such an embodiment may facilitate displaying display light to cover a two-dimensional space, i.e., the retroreflective display surface 122 of retroreflective screen 120.

[0017] Display device 112 may have one or more of the following features: In some embodiments, the display device may consume 3 watts or less. In some embodiments, the display device may consume 2 watts or less. In some embodiments, the display device may consume 1 watt or less. In some embodiments, the display device may consume 0.5 watts or less. In some embodiments, the display device may consume 0.4 watts or less. In some embodiments, the display device may consume 0.3 watts or less. Display device 112 may be configured to emit light within the visible spectrum, i.e., light having a peak wavelength within a range of 380 nanometers (nm) to 750 nm. In some embodiments, display device 112 may be configured to emit monochromatic light, i.e., light having a narrow wavelength band. In some embodiments, display device 112 may be configured to emit green monochromatic light having a peak wavelength within a range of 495 nm to 570 nm.

[0018] A pixel array may be defined by a number m of horizontal pixels and a number n of vertical pixels, as shown in array 300 of FIG. 3. In some embodiments, the number of horizontal pixels may be at least 120 pixels. In some embodiments, the number of vertical pixels may be at least 100 pixels. In some embodiments, the number of horizontal pixels may be at least 480 pixels and the number of vertical pixels may be at least 400 pixels. It is further contemplated that the horizontal to vertical pixel ratio may be 6:5, and in further embodiments, any array (cropped or uncropped) having a 6:5 ratio, a horizontal pixel count of at least 120 pixels, and a vertical pixel count of at least 100 pixels is contemplated.

[0019] In some embodiments, pixel array 300 may be operable to "bin" groups of adjacent pixels to operate simultaneously and function as a single pixel, as shown in pixel subgroup 302. For example, if the horizontal pixel count is at least 480 pixels and the vertical pixel count is at least 400 pixels, a group of four pixels in a 2x2 array may be binned to operate simultaneously as a single pixel. As another example, if the horizontal pixel count is at least 960 pixels and the vertical pixel count is at least 800 pixels, a group of 16 pixels in a 4x4 array may be binned to operate simultaneously as a single pixel. Any number of pixels in any arrangement may be binned, resulting in an effective array of binned pixels of at least 120 horizontal binned pixels by 100 vertical binned pixels, and is considered within the scope of the present invention.

[0020] In order to minimize the weight of the power supply elements 116 (e.g., batteries, power transformers, or adapters) of the goggle device 102 from a voltage or power regulation standpoint, it is necessary to minimize the power consumption by the display device 112. In this embodiment, the maximum power consumption of the display device 112 is 15 mW or less. Furthermore, the optical power of the light emitted by the display device 112 must be sufficiently bright so that reflections from the display screen 120 are visible to the patient's eye 104 at a distance d, as discussed in more detail below. In some embodiments, the optical power of the light emitted from each pixel or each binned pixel of the pixel array may be at least 16 nW, at least 64 nW, at least 256 nW, or in a range of at least 8 nW to at least 512 nW.

[0021] Additionally, display device 112 may be operable to simultaneously or sequentially change or illuminate pixels and / or binned pixels sufficiently rapidly to simulate movement and generate a video display. Each change of display device 112 may be considered a frame of the video display, with the resulting frames per second (FPS) depending on how quickly display device 112 can change the pixels / binned pixels. In some embodiments, display device 112 may have a frame rate of at least 15 FPS. In some embodiments, display device 112 may have a frame rate of at least 20 FPS. In some embodiments, display device 112 may have a frame rate of at least 25 FPS. In some embodiments, display device 112 may have a frame rate of at least 30 FPS. In some embodiments, display device 112 may have a frame rate of at least 35 FPS. In some embodiments, display device 112 may have a frame rate of at least 40 FPS.

[0022] The projection device 110 may further include an optical lens 114 disposed in optical communication with the display device 112. Specifically, the optical lens 114 may be disposed within an illumination path 111 of the projection device 110, which is defined by the light emission direction of the display device 112. Such emission direction may originate from an emission lens (not shown) fabricated on each micro LED pixel of the display device 112. Light emitted from the display device 112 may be refracted by the optical lens 114 and projected therefrom. The direction of light projected from the optical lens 114 may be defined as a field of view 115 of the optical lens 114 / projection device 110. The retroreflective screen 120 may be positioned relative to the goggle device 102 to overlap the field of view 115. In this embodiment, the optical lens 114 defines a field of view 115 in front of the projection device 110, characterized by a horizontal angular dimension of 60 degrees and a vertical angular dimension of 50 degrees. In another embodiment, the field of view 115 may be characterized by a horizontal angular dimension ranging from 50 degrees to 70 degrees and a vertical angular dimension ranging from 40 degrees to 60 degrees.

[0023] The goggle device 102 may further include multiple components to enable ocular imaging. These components may include an infrared light source 134, an imaging sensor 132, a dichroic reflective device 138, and a bandpass filter and / or electro-optical device 136. The dichroic reflective device 138 and the bandpass filter and / or electro-optical device 136 may be combined into a single device, as shown as 136 in FIG. 4 . The infrared light source 134 may be positioned to emit infrared light that is incident on the patient's eye 104, i.e., light having a peak intensity within a wavelength range of 700 nm to 1,000 nm. Such incidence may occur when light emitted from the infrared light source 134 directly impinges on the patient's eye 104 or indirectly after being reflected by a reflective structure, such as a hot mirror 138, which may also be included in the goggle device 102.

[0024] The patient's eye 104 may reflect infrared light incident thereon. Such reflected infrared light may be received and measured by the imaging sensor 132. The imaging sensor 132 may be any imaging device operable to measure infrared light, including, but not limited to, charge-coupled devices and active pixel sensors, including CMOS and N-type MOS devices. The imaging sensor 132 may be positioned to receive reflected infrared light directly from the patient's eye 104 or indirectly, such as when infrared light reflected from the patient's eye 104 strikes a hot mirror 138 and is thereby reflected back toward the imaging sensor 132. The reflected infrared light measured by the imaging sensor 132 may be analyzed to provide eye movement measurements of the patient's eye 104 in response to what the patient's eye observes on the retroreflective screen 120, i.e., the stimuli or images generated by the projection device 110 and projected onto the retroreflective screen 120. The included eye imaging components may further include one or both of a fixed focus lens 135 and a variable focus lens 133 optically positioned intermediate the dichroic hot mirror 138 and the image sensor 132 to focus the reflected infrared light passing therethrough so that it can be more clearly measured by the image sensor 132.

[0025] The dichroic reflective and / or electro-optical device 136 may be configured to selectively allow light within a first wavelength range to pass and selectively reflect light within a second wavelength range. In this embodiment, the dichroic reflective and / or electro-optical device 136 may be electrically configured to allow visible light, i.e., light having a peak intensity within a wavelength range of 380 nm to 750 nm, to pass through. Thus, reflected light 106 from the retroreflective screen 120 may pass through the dichroic reflective and / or electro-optical device 136 and be incident on and observable by the patient's eye 104. In some embodiments, the first wavelength range over which light may pass through the dichroic reflective and / or electro-optical device may be narrower than all visible light. In some embodiments, the first wavelength range may be similar to or equal to the wavelength range of light emitted by the display device 112. In some embodiments, the first wavelength range may be 495 nm to 570 nm. In some other embodiments, the first wavelength range may be electro-optically controlled to be absorbed or scattered, thereby making the light path of the first wavelength range opaque to the patient's eye. The second wavelength range may be configured to reflect light emitted by the infrared light source 134 and light reflected by the patient 104, specifically infrared light reflected by the patient's eye 104. Thus, the second wavelength range may be 700 nm to 1,000 nm.

[0026] Embodiments of the electro-optical device 136 may be any material or device operable to cause the reflection / transmission / absorption / scattering described above, including, but not limited to, dichroic reflectors, switchable privacy smart films / glasses including embodiments of polymer dispersed liquid crystals and suspended particles, and electrochromic films / glasses. If electrochromic films / glasses are used, the goggle device 102 may further comprise components necessary to control the state of the electrochromic films / glasses. If switchable privacy smart films / glasses are used, the goggle device 102 may further comprise components necessary to control the state of the privacy switchable smart films / glasses.

[0027] In this embodiment, the combination of the display device 112 and the optical lens 114 may be such that the light projected thereby has a projection accuracy on the retroreflective screen 120 within at least one of the ranges of -1.0 degrees to 1.0 degrees, -0.5 degrees to 0.5 degrees, or -0.25 degrees to 0.25 degrees.

[0028] The retroreflective screen 120 may be configured to retroreflect light projected thereon, i.e., reflect light back toward the light source. The retroreflective screen 120 may comprise any retroreflective material known in the art, including, but not limited to, fabrics, laminates, films, paints, and combinations thereof. In some embodiments, the retroreflective screen 120 may comprise a flexible substrate coated with a retroreflective layer of material that facilitates storage of the retroreflective screen 120.

[0029] The retroreflective screen 120 may be positioned a distance d from the goggle device 102 within the field of view 115. The distance d may be in the range of 1 meter to 3 meters. In one embodiment, the distance d is 2 meters. The distance d may be selected as a function of various parameters of the display device 112, including, but not limited to, the projection accuracy of the light projected onto the retroreflective screen 120, the angular resolution of the light retroreflected by the retroreflective screen 120, the field of view of the display device 112, and the intensity of the light emitted by the display device 112.

[0030] In some embodiments, the retroreflective screen 120 may be configured to have an angular resolution of light reflected thereby of at least one of 1.0 degrees or less, 0.5 degrees or less, or 0.25 degrees or less.

[0031] Referring now to FIG. 4 , additional details regarding the goggle device 102 are provided. The goggle device 102 may include a housing 103 configured to hold and / or accommodate components of the projection device 110 and components for performing the eye imaging described above. Furthermore, the housing 103 may be configured to generally conform to the shape of a human head, allowing patients with heads of various sizes and shapes to wear the goggle device 102. The dichroic reflective and / or electro-optical device 136 may be positioned in front of the patient's eyes when the goggle device 102 is worn by the patient. The image sensor and infrared light source may be positioned within the housing 103 adjacent an opening 105 in the housing 103 through which electromagnetic radiation (EMR) can pass. One or more of the above-described optical systems, including one or more of the optical lens 114, the variable focus lens 133, and the fixed focus lens 135, may be positioned in optical communication with the opening 105 and may be further carried by an optical housing 107 attached to the housing 103. Additionally, opening 105 may be positioned such that it is not visible to the patient's eye, such that EMR passing through opening 105 cannot be directly observed by the patient.

[0032] Referring now to FIG. 5 , a method 500 according to one embodiment of the present invention is shown. Method 500 may include, at step 502, positioning a projection device near one or more patient's eyes. The projection device may comprise a micro LED display device comprising an array of light-emitting pixels and an optical lens disposed in optical communication with the micro LED display device. Method 500 may continue, at step 504, operating the micro LED display device to emit light from the array of light-emitting pixels. Method 500 may continue, at step 506, projecting light emitted by the micro LED display device from the optical lens onto at least a portion of a retroreflective screen within a field of view of the optical lens. At step 508, method 500 continues by retroreflecting the light projected onto the retroreflective screen by the optical lens toward one or more patient's eyes. Method 500 may conclude, at step 510, by observing movement of one or more patient's eyes in response to the one or more patient's eyes observing the retroreflected light.

[0033] The light emitted by the micro LED display device may be monochromatic green light. Operating the micro LED display device to emit light from the light-emitting pixel array may include operating the micro LED device to emit light from at least one pixel of the pixel array or a group of adjacent pixels of the pixel array such that the angular resolution of the emitted light on the retroreflective screen is 0.5 degrees or less. Operating the micro LED display device to emit light from the light-emitting pixel array may include emitting light from at least one pixel of the pixel array or a group of adjacent pixels of the pixel array such that a projection of the emitted light has a projection accuracy on the retroreflective screen within a range of -0.5 degrees to 0.5 degrees. Positioning the projection device near one or more patient's eyes may include positioning goggles including the projection device on the patient's head. Operating the micro LED display device to emit light from the light-emitting pixel array may include emitting light such that a two-dimensional motion simulation is projected onto the retroreflective screen.

[0034] As mentioned above, projection device 110 may generally be positioned between where the patient's eyes are intended to be located. In this embodiment, projection device 110 may be positioned on bridge portion 109 of housing 103, which may be positioned over the bridge of the patient's nose when goggle device 102 is worn by the patient. Such a location is exemplary only, and placing projection device 110 anywhere on housing 103 is contemplated and within the scope of the present invention.

[0035] Some of the exemplary aspects of the present invention may be advantageous in solving the problems described herein, as well as other problems not described herein that may be discoverable by one of ordinary skill in the art.

[0036] While the above description contains many specific details, these should not be construed as limiting the scope of any embodiment, but as illustrative of the presented embodiment. Many other variations and modifications are possible within the teachings of the various embodiments. While the present invention has been described with reference to exemplary embodiments, those skilled in the art will recognize that various changes may be made without departing from the scope of the invention and that equivalents may be substituted for elements thereof. Furthermore, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope of the invention. Therefore, the present invention is not limited to the particular embodiment disclosed as the best or only mode contemplated for carrying out the invention, but is intended to include all embodiments falling within the description of the invention. Furthermore, although the drawings and description disclose exemplary embodiments of the invention and specific terms may be used, unless otherwise noted, these terms are used in a generic and descriptive sense only and not for purposes of limitation, and therefore do not limit the scope of the invention in any way. Furthermore, the use of terms such as "first," "second," etc., does not denote order or importance, but rather is used to distinguish one element from another. Furthermore, the use of terms such as "a," "an," etc. does not denote a limitation of quantity, but rather denotes the presence of at least one of the referenced item.

Claims

1. An eye movement measuring device (100), A projection device (110), comprising: a micro LED display device (112) comprising an array of light-emitting pixels (300); a projection device (110) comprising: an optical lens (114) disposed in optical communication with the micro LED display device (112), the optical lens (114) configured to project light within a field of view of the optical lens (114); a retroreflective screen (120) configured to be positioned to overlap the field of view of the optical lens (114); the projection device (110) is configured to be positioned near one or more eyes of a patient; An eye movement measurement device (100), wherein the retroreflective screen (120) is configured to retroreflect light toward the one or more patient's eyes.

2. The eye movement measurement device (100) of claim 1, wherein the micro LED display device (112) is monochromatic.

3. The eye movement measurement device (100) of claim 2, wherein the micro LED display device is configured to emit green light.

4. 2. The eye movement measurement device (100) of claim 1, wherein light emitted from at least one of a pixel of the light-emitting pixel array (300) or a group of adjacent pixels of the light-emitting pixel array (300) and retroreflected by the retroreflective screen (120) has an angular resolution on the retroreflective screen (120) of 0.5 degrees or less.

5. 2. The eye movement measurement device (100) of claim 1, wherein light emitted from at least one of a pixel of the pixel array or a group of adjacent pixels of the pixel array has a projection accuracy on the retroreflective screen (120) within a range of −0.5 degrees to 0.5 degrees.

6. 2. The eye movement measurement device (100) of claim 1, wherein the pixel array has dimensions of at least 120 horizontal pixels by 100 vertical pixels.

7. 2. The eye movement measurement device (100) of claim 1, wherein the field of view of the optical lens (114) is greater than or equal to 60 degrees horizontally and greater than or equal to 50 degrees vertically.

8. The eye movement measurement device (100) of claim 1, wherein the retroreflective screen (120) comprises at least one of a retroreflective fabric, a retroreflective laminate, a retroreflective film, and a retroreflective paint.

9. 2. The eye movement measuring device (100) according to claim 1, wherein the projection device (110) is constituted by a goggle device (102) worn by the patient.

10. 10. The eye movement measuring device (100) of claim 9, wherein the projection device (110) is disposed between two eyepiece openings of the goggle device (102) and emits light in the direction of the patient's field of vision when the goggle device (102) is worn.

11. an infrared light source (134); an image sensor (132); a dichroic reflective device (138) configured to allow transmission of visible light and reflection of infrared light, the dichroic reflective device (138) being positioned in optical communication with each of the infrared light source (134), the image sensor (132), and the patient's eye; The eye movement measuring device (100) of claim 1 further comprising:

12. 2. The eye movement measurement device (100) of claim 1, wherein the micro LED display device (112) is operable to emit light such that a two-dimensional movement simulation is projected onto the retroreflective screen (120).

13. 1. A method for conducting an oculomotor test, comprising: Positioning a projection device (110) near one or more patient's eyes, said projection device (110) comprising: a micro LED display device (112) comprising an array of light-emitting pixels (300); an optical lens (114) disposed in optical communication with the micro LED display device (112); operating the micro LED display device (112) to emit light from the light-emitting pixel array (300); projecting light emitted by the micro LED display device (112) from the optical lens (114) onto at least a portion of a retro-reflective screen (120) within a field of view of the optical lens (114); retroreflecting light projected by the optical lens (114) onto the retroreflective screen (120) toward the one or more patient's eyes; observing movement of the one or more patient's eyes in response to the one or more patient's eyes observing the retroreflected light; A method comprising:

14. 14. The method of claim 13, wherein the light emitted by the micro LED display device (112) is monochromatic green light.

15. 14. The method of claim 13, wherein operating the micro LED display device (112) to emit light from the light-emitting pixel array (300) comprises operating the micro LED device to emit light from at least one pixel of the pixel array or a group of adjacent pixels of the pixel array such that the angular resolution of the emitted light on the retroreflective screen (120) is 0.5 degrees or less.

16. 14. The method of claim 13, wherein operating the micro LED display device (112) to emit light from the light-emitting pixel array (300) comprises emitting light from at least one pixel of the pixel array or a group of adjacent pixels of the pixel array such that a projection of the emitted light has a projection accuracy on the retroreflective screen (120) within a range of −0.5 degrees to 0.5 degrees.

17. 14. The method of claim 13, wherein positioning the projection device (110) near one or more of the patient's eyes comprises positioning goggles including the projection device (110) on the patient's head.

18. 14. The method of claim 13, wherein operating the micro LED display device (112) to emit light from the light-emitting pixel array (300) comprises emitting light such that a two-dimensional motion simulation is projected onto the retroreflective screen (120).

19. An eye movement measuring device (100), A goggle device (102) configured to be worn on a patient's head, comprising: Two eyepiece openings; a projection device (110) disposed between the eyepiece openings, a monochromatic micro LED display device (112) comprising an array of light-emitting pixels (300) having dimensions of at least 120 horizontal pixels by 100 vertical pixels; a projection device (110) comprising: an optical lens (114) disposed in optical communication with the micro LED display device (112), the optical lens (114) configured to project light within a field of view of the optical lens (114), the field of view being greater than or equal to 60 degrees horizontally and greater than or equal to 50 degrees vertically; an infrared light source (134); an image sensor (132); a goggle device (102) configured to allow transmission of visible light and reflection of infrared light, the goggle device comprising: a dichroic reflective device (138) positioned in optical communication with the infrared light source (134), the image sensor (132), and each of one or more patient's eyes; a retroreflective screen (120) configured to be positioned to overlap the field of view of the optical lens (114), the retroreflective screen including at least one of a retroreflective fabric, a retroreflective laminate, a retroreflective film, and a retroreflective paint; the retroreflective screen (120) is configured to retroreflect light toward the one or more patient's eyes; An eye movement measurement device (100), wherein light emitted from at least one pixel of the light-emitting pixel array (300) or a group of adjacent pixels of the light-emitting pixel array (300) and retroreflected by the retroreflective screen (120) has an angular resolution of 0.5 degrees or less on the retroreflective screen (120).

20. 20. The eye movement measurement device (100) of claim 19, wherein light emitted from at least one of a pixel of the pixel array or a group of adjacent pixels of the pixel array has a projection accuracy on the retroreflective screen (120) within a range of −0.5 degrees to 0.5 degrees.

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