Head-mounted device-based system for measuring binocular alignment

Abstract

A method of determining binocular alignment includes measuring an uncoupling phoria of a patient at a first simulated distance by: presenting a fusible image including a target having a first disparity corresponding to the first simulated distance using a stereoscopic display of a head-mounted device at a screen distance; presenting the target having the first disparity for a first eye and presenting an uncoupling null target image for a second eye to present a non-fusible image, and measuring an uncoupling phoria in response to the presentation of the non-fusible image using an eye tracker of the head-mounted device; and including determining a vergence of the patient at the first simulated distance by: presenting a fusible image having the first disparity corrected for the measured uncoupling phoria for the first and second eyes; measuring a coupling phoria in response to the presentation of the fusible image; and determining the vergence as a combination of the uncoupling phoria and the coupling phoria.

Description

[0001] Cross-references to related applications

[0002] This application is a continuation-in-part of U.S. Patent Application 17 / 179,402, filed February 19, 2021, entitled "System for Measuring Binocular Alignment with Adjustable Displays and Eye Trackers," and claims the benefit thereto. This application is a continuation-in-part of U.S. Patent Application 16 / 579,826 (now U.S. Patent No. 11,589,745), filed September 23, 2019, entitled "Method and System for Measuring Binocular Alignment," and filed September 5, 2017, entitled "Method and System for Measuring Binocular Alignment." A continuation-to-file of U.S. Patent Application No. 15 / 696,161 (now U.S. Patent No. 10,420,467) entitled “System for Measuring Binocular Alignment”, all of which are hereby incorporated herein by reference in their entirety. Technical Field

[0003] This invention generally relates to methods and systems for measuring visual acuity, and more specifically to measuring binocular alignment. Background Technology

[0004] With normal vision, an individual can focus on objects at different distances. Ideally, an individual can focus on distant objects, known as distance vision, and on near objects, known as near vision. The eye's optical system uses many muscles to change focus between these distances. These muscles adjust various aspects of the eye when switching between distance and near vision. Muscle adjustment includes making subtle changes to the shape of the lens to adjust its focus, rotating the eyeball to rotate its optical axis, and changing the size of the pupil.

[0005] Presbyopia is a natural deterioration of near vision caused by the loss of flexibility in the eye's lens as we age. Presbyopia can be partially compensated for by wearing "reading" glasses that correct the refractive error in near vision, allowing the eye to focus less intensely when looking at near objects. People with presbyopia require different optical corrections for distance and near vision. However, using two pairs of glasses and frequently changing them can be distracting. To avoid constantly changing glasses, bifocal lenses that provide different optical corrections for distance and near vision can be used. The transition between these two visual areas can be abrupt or gradual. The latter type of lens is called a progressive addition lens (PAL). Abrupt-change bifocal lenses have a visible line separating the two visual areas, while PAL lenses do not have a visible line or edge between areas with different refractive powers.

[0006] Despite all these advancements, several types of vision-related discomfort persist. One of these discomforts is linked to shifts in habits associated with modern digital lifestyles. Numerous and increasingly common professions require workers to spend significant and increasing amounts of time at close range on digital interfaces, including computer screens and mobile devices. The same is true for many people's personal lives, spending hours playing video games, sending and receiving text messages, and checking for updates on their phones. All these shifts in professions and behaviors have rapidly increased the time people spend looking at digital screens, devices, monitors, and displays at closer distances than ever before. This increased time spent focusing the eyes on near visual targets places excessive demands on the muscles involved in near vision, often pushing them beyond their comfort levels. This can lead to fatigue, discomfort, pain, or even digital-induced migraines. To date, there is no widely accepted consensus on the precise causal mechanisms underlying these digital device-related visual discomforts, pain, and migraines, although millions of people experience these symptoms daily. Therefore, there is a need for eyeglasses or other optometric solutions that can alleviate digital eye discomfort.

[0007] Figures 1-4 illustrate the basic problems of binocular misalignment. Figure 1A The illustration shows how our vision adjusts in two ways when we look at a near object, such as the cross shown. First, we adjust the optical power of our eyes 1-1 and 1-2 to image the near object at a distance L onto the retina of each eye. This is often referred to as the accommodative response A. Second, we rotate our eyes 1-1 and 1-2 inward by an angle... This is to ensure that the visual axes 2-1 and 2-2 of the eye point to the same nearby object. This response is often referred to as accommodative convergence (AC). For obvious geometric reasons, the angle of accommodative convergence (AC) relative to a straight forward reference axis is... The distance L is directly related to the adjustment response A: For healthy, well-aligned eyes, the ratio of accommodative convergence AC to accommodative response A, AC / A, is geometrically defined as a function of object distance L and interpupillary distance PD of both eyes.

[0008] Figures 1B-1C The illustration shows various forms of accommodative inaccuracy that the eye frequently exhibits. Figure 1B In the middle, both eyes turn inward, but to a lesser extent than the geometry requires. This results in an accommodative convergence angle. The misalignment angle is smaller than the geometrically required angle. More specifically, the visual axes of eyes 2-1 and 2-2 should point in the direction of necessary accommodative alignment to see nearby objects correctly, but instead, they are rotated inward to a lesser degree and point in the direction of relaxed or natural accommodative alignment.

[0009] Figure 1C The illustration shows a case of minor rotational asymmetry. In the illustrated case, the visual axis 2-1 of the first eye 1-1 correctly points in the direction of the necessary accommodative alignment, while the visual axis 2-2 of the second eye 1-2 only turns inward in the direction of relaxed or natural accommodative alignment, i.e., it is misaligned by an accommodative misalignment angle. .

[0010] Figures 2A-2D The illustrations depict some types of accommodation misalignment. Different schools of optometry and monographs exhibit some differences in the definition of misalignment, and the techniques used to characterize these misalignments also differ. Therefore, the definitions shown here are merely illustrative, and analogues and equivalents are also included within the scope of the terminology described.

[0011] To place the misalignment discussed in the proper context, we first introduce the concept of image fusion. When our two eyes look at the same object, each eye creates its own visual perception. These perceptions are relayed from the eyes to the visual cortex, where the brain fuses the two images and creates a three-dimensional (3D) perception of the viewed object. This image fusion can be tested using an optometric diagnostic system. For example, two separate objects of the same shape can be projected into each eye using deflectors, prisms, and mirrors, making the two projections appear as if they came from a single object. These visual perceptions are then fused by the brain into a single perceived image. Objects projected in this way are called fusionable objects, presenting fusionable images.

[0012] If the distance between two objects increases, or the deflection angle increases, or the shape of the objects is modified in an experiment, the projections entering the two eyes will begin to differ. At a certain distance or difference between the objects, the difference between the visual perceptions of the two eyes exceeds a threshold, and the brain stops fusing the two images into a single perception. Objects with such differences in distance, angle, or shape are called non-fusible objects, thus presenting non-fusible images.

[0013] Through this preparation Figures 2A-2D The illustration depicts the concept of fixation disparity, measured by a testing device commonly known as a mallet box. The mallet box displays two vertically aligned bars and an "anchor" at the "XOX" level. In some implementations, the two bars can be laterally displaced. In others, an adjustable mirror or prism is placed in front of the patient's eyes to achieve the same horizontal displacement. Using appropriately selected optics, for the first eye 1-1, only one of the anchor and bars is shown as the centered bar 5-1-c; for the second eye 1-2, the same anchor and only the other bar are shown as the centered bar 5-2-c. The anchor and the centered bars 5-1-c and 5-2-c are clearly fusionable. Therefore, the brain of a patient without accommodative misalignment problems will correctly fuse these images.

[0014] Figure 2B The illustration shows that patients with accommodative misalignment will not be able to properly fuse images. What is typically observed is that while the images of the anchor seen by both eyes are correctly fused into a single image, the bars are perceived as shifted. The first eye 1-1 perceives the shifted bar 5-1-s, while the second eye 1-2 perceives the shifted bar 5-2-s. The angle between the line to the center of the image and one of the visual axes 2-1 and 2-2 is shown. This is called fixation difference.

[0015] Figures 2C-2D The diagram illustrates a method for measuring the angle required to counteract or compensate for gaze differences. Figure 2C In this system, the two bars are counter-shifted. The counter-shifted bar 5-1-x is shown for the first eye 1-1, and the counter-shifted bar 5-2-x is shown for the second eye 1-2. The bars are counter-shifted until the patient perceives the two bars as aligned. The angles corresponding to these counter-shifts are measured between the visual axis and the line to the counter-shifted bar. This is often referred to as associated phoria. Figure 2DIn this system, the bars are not reversed. Instead, adjustable or replaceable prisms 7 are inserted in front of the patient's eye. These prisms are adjusted or replaced until the patient perceives the two bars aligned. The prism angle or the angle of refraction of the refractive axis is then reported as associated heterophoria. .

[0016] Figure 3 The diagram illustrates how increasing partial associative heterophoria partially compensates for fixational aberration. Strictly speaking, (fully) associative heterophoria that fully compensates for fixational aberration is given by the intersection of this curve and the partial associative heterophoria visual axis. If human vision were purely optical, then partial associative heterophoria would simply be equal to the negative of the partially compensated fixational aberration. Therefore, the curve would be a straight line passing through the origin, inclined at -45 degrees, pointing from the upper left to the lower right. However, Figure 3 The illustration shows that human vision is more complex, and that perception and image processing play a crucial role in it. Figure 3 Four types of relationships between partially compensated fixational differences and partially associative heterophoria are illustrated. Visually, these lines are not straight lines, none pass through the origin, and two of them do not even intersect the horizontal axis. These Type II and Type III relationships imply that no amount of partially associative heterophoria can fully compensate for fixational differences. Therefore, identifying associative heterophoria that fully compensates for a patient's fixational differences remains a significant challenge. A convention is mentioned at the end: if the eye does not turn inward to the necessary extent, the fixational difference is called "exo," while in the rare cases where the eye turns inward excessively, the fixational difference is called "eso."

[0017] Figures 4A-4C The diagram illustrates the associated visual aberration, termed disassociated phoria. To characterize disassociated phoria, a similar method can be used... Figures 2A-2D The experiment differed in that, instead of showing fusion-compatible images 5-1 and 5-2, the optometrist showed non-fusion-compatible images 6-1-s and 6-2-s for the first eye 1-1 and the second eye 1-2. Figure 4A In this context, these non-mergeable images are crosses and bars. For example... Figure 4B As shown, once the eyes fail to fuse images, typically one or both visual axes will rotate outward. In the asymmetric case shown, the visual axis 2-2 of the second eye 1-2 rotates outward due to an accommodative misalignment angle. Measure the angle of outward rotation. This is referred to as non-associated latent strabismus. In various applications, as described below, non-associated latent strabismus is evenly distributed across both eyes, therefore the non-associated latent strabismus in each eye is equal to... In some cases, such as... Figure 1C As shown, non-associated latent strabismus It may appear unevenly, and therefore must be distributed between the eyes.

[0018] Figure 4C The following scenario is shown in particular clarity: when no image is simply shown to the second eyes 1-2, their field of vision is obstructed. This is an extreme case of non-fusionable images. For Figure 4B In response to obstruction, the visual axis 2-2 of the second eye 1-2 rotates outward to measure the non-associated lacrimal angle. .

[0019] As a quantitative representation of accommodative misalignment, including fixation difference and unrelated heterophoria, some practitioners use the AC / A ratio, which measures the impact of misalignment. AC / A is calculated by subtracting fixation difference from the accommodative convergence angle. (using "prism diopter") The AC is expressed in its tangent form and divided by the accommodative distance L (expressed in diopter D). A typical definition of AC is... The AC / A ratio is expressed as prism diopter. For average visual performance, the AC / A ratio is 6-6.5. / D is necessary, and it is worth noting that in a large portion of the population, the average AC / A ratio affected by inaccuracies was measured to be approximately 3.5. / D. It is clear that various forms of regulatory misalignment affect a large proportion of the population, and any progress in mitigating this condition is invaluable.

[0020] A surprising fact in the field of optometry is that the correlated and uncorrelated heterophoria angles determined by experienced practitioners show a very wide range of variation. Experiments conducted by different optometrists on the same patient, and sometimes even by the same optometrist at different times, have reported variations in prism refractive power. The standard deviation of the distribution of the oblique angles is as high as 3. (1) The prism diopter corresponds to 1 cm of prism refraction at a distance of 1 meter. The large variability of these methods hinders the effective determination and compensation of accommodation misalignment.

[0021] The unusually large standard deviation may be due to a number of factors. These factors include the following: (1) The identified methods use the patient’s subjective response as a key input. (2) Some methods use central images while others use peripheral images to determine associated heterophoria. The relative accuracy and relevance of these methods have not been rigorously evaluated. (3) Most practitioners use a single measurement or a single method and therefore cannot benefit from the potentially important medical information that could be collected by conducting multiple tests. (4) In previous exploratory projects, the applicant also found that the prism response of the eye is quite different for moving test images. However, understanding the relationship between optimal prism correction based on static and moving test images is in its early stages. (5) While there are several methods that can define prism misalignment and they produce different prism predictions and diagnoses, ultimately a single prism needs to be formed in the eyeglasses. How to convert and combine various diagnostically determined prism corrections into a single prism prescription is far from obvious. The applicant is unaware of key studies on how the efficacy and variability of prism prescriptions depend on possible combinations of identified prism corrections.

[0022] For all the reasons mentioned above, determining the optimal prism power to compensate for accommodative misalignment remains a pressing medical need. Furthermore, there is a need for devices that can perform these measurements with high precision, and devices that are smaller and therefore cheaper, which would help these technologies gain wider acceptance and adoption within the medical community. Summary of the Invention

[0023] To address the aforementioned medical needs, some embodiments include a method for determining binocular alignment, the method comprising: (a) measuring a patient’s unassociated heterophoria at a first simulated distance by: presenting a fusionable image at a screen distance using a stereoscopic display of a head-mounted device, comprising a target for a first eye and a second eye having a first parallax corresponding to the first simulated distance; presenting a non-fusionable image by presenting the target for the first eye having the first parallax and an unassociated targetless image for the second eye at a screen distance using a stereoscopic display of a head-mounted device, and measuring unassociated heterophoria in at least one of the first and second eyes in response to the presentation of the non-fusionable image using an eye tracker of the head-mounted device; and (b) determining a patient’s vergence at the first simulated distance by: presenting a fusionable image at a screen distance using a stereoscopic display of a head-mounted device, comprising a first parallax having a measured unassociated heterophoria correction for the first and second eyes; measuring associated heterophoria in response to the presentation of the fusionable image using an eye tracker; and determining the vergence as a combination of unassociated heterophoria and associated heterophoria. Attached Figure Description

[0024] Figures 1A-1C The diagram illustrates various regulatory misalignments.

[0025] Figures 2A-2D The diagram illustrates a method for determining the type of adjustment misalignment.

[0026] Figure 3 The diagram illustrates four types of relationships between fixation differences and partially associative latent strabismus.

[0027] Figures 4A-4C The illustration shows a method for determining non-associated latent strabismus.

[0028] Figure 5 The diagram illustrates a system used to determine binocular misalignment.

[0029] Figures 6A-6B An embodiment of a system for determining binocular misalignment is illustrated.

[0030] Figure 7 The illustration shows an IR image of an eye tracker.

[0031] Figures 8A-8B An embodiment of a system for determining binocular misalignment is illustrated.

[0032] Figure 9 An embodiment of a system for determining binocular misalignment is illustrated.

[0033] Figures 10A-10B An embodiment of the adjustable optics is illustrated.

[0034] Figure 11 The illustration shows a method for determining binocular misalignment.

[0035] Figure 12 The illustration shows exemplary details of the measurement steps.

[0036] Figures 13A-13D The diagram illustrates the steps involved in performing the measurement procedure.

[0037] Figure 14 The illustration shows exemplary details of the determination steps.

[0038] Figures 15A-15C The diagram illustrates the steps involved in performing the determination process.

[0039] Figure 16 The following embodiment of a method for determining binocular misalignment is illustrated in the diagram.

[0040] Figure 17 The diagram illustrates a system used to determine eye alignment.

[0041] Figures 18A-18B An embodiment of the first optical unit is illustrated.

[0042] Figure 19 The diagram illustrates a system used to determine eye alignment.

[0043] Figure 20 The illustration shows a perspective view of the first optical unit.

[0044] Figure 21 The illustration shows a front view of a system used to determine eye alignment.

[0045] Figure 22 An embodiment of a system for determining eye alignment, having a graphical user interface and a patient communication interface, is illustrated.

[0046] Figure 23 An embodiment with an automated refractometer is illustrated.

[0047] Figure 24 An embodiment of a system for determining eye alignment is illustrated.

[0048] Figure 25 An embodiment of the first optical unit is illustrated.

[0049] Figures 26A-26B A head-mounted device-based system for measuring eye alignment is shown.

[0050] Figure 27 The main components of the head-mounted device 500 are shown at the conceptual level.

[0051] Figure 28 The main steps of method 600 for determining eye alignment are shown.

[0052] Figures 29A-29B Ray tracing is shown in the rendering of an image in a head-mounted device 500.

[0053] Figure 30 The illustration shows the lateral optical adjustment of some head-mounted devices 500 according to the patient's interpupillary distance.

[0054] Figures 31A-31B The illustration shows specific embodiments of step 622, which presents a mergeable image, and step 624, which presents a non-mergeable image. Detailed Implementation

[0055] The system described in this patent document addresses the aforementioned specific medical needs in at least the following ways: (1) The described system and method determine prism correction solely through objective measurements, without subjective input from the patient. This alone greatly reduces patient-to-patient and practitioner-to-practitioner variation in outcomes. In fact, studies using the applicant's system and method on a large sample of patients have determined prism correction with standard deviations from the aforementioned 3 Dropped to well below 1 The significant reduction in the standard deviation of the results alone establishes the method described herein as a quantitative predictive diagnostic method. (2) Due to a new understanding of how peripheral and central prism corrections are related, the system and method use both central and peripheral test images. Therefore, the system and method described herein are a promising platform for determining the optimal compromise prism prescription that achieves the best compromise between compensating for both central and peripheral accommodative misalignment. (3) The method described has two stages, and thus, it determines the final prism correction in the second stage based on the important misalignment information obtained in the first stage. In this way, the method integrates the knowledge determined by different methods and benefits from the information determined by all methods. (4) One of the stages of the method involves moving test images. Therefore, the final determined prism correction also captures and integrates the dynamic prism response of the eye. (5) The reliable reproducibility and small variability of the above large-scale studies provide a compelling argument that the applicant's method combines the outputs of different methods in an objectively effective manner to produce a single optimized and objective prism correction. The five aspects described herein provide advantages individually and in combination.

[0056] Figure 5 Figure 10 illustrates the system 10 used to determine binocular alignment, and Figures 11-16 The diagram illustrates a corresponding method 100 for determining eye alignment.

[0057] Figure 5 The illustration shows that, in some embodiments, a system 10 for determining binocular alignment may include a stereoscopic display 20 for projecting visible images to a first eye 1-1 and a second eye 1-2; an adjustable optics 30 for modifying the projected visible images according to apparent distance; an eye tracker 40 for tracking the orientation of the first eye 1-1 and the second eye 1-2; and a computer 50 coupled to the stereoscopic display 20, the adjustable optics 30, and the eye tracker 40 for managing the determination of binocular alignment. In the following, the eyes will be labeled as the first eye 1-1 and the second eye 1-2. This label may correspond to the left eye and the right eye, or vice versa.

[0058] Figure 6ADetailed illustrations of some embodiments of system 10 are shown. In some embodiments, eye tracker 40 may include infrared light-emitting diodes or IR LEDs 42-1 and 42-2 and infrared light sources 44-1 and 44-2, the IR LEDs 42-1 and 42-2 being positioned near the front of system 10 to project an infrared eye-tracking beam onto a first eye 1-1 and a second eye 1-2, and the infrared light sources 44-1 and 44-2 being used to illuminate the first eye 1-1 and the second eye 1-2 with infrared imaging light. Both the infrared eye-tracking beam and the infrared imaging light are reflected from the eyes 1-1 and 1-2. Eye tracker 40 may also include infrared (IR) telescopes 46-1 and 46-2 with infrared (IR) cameras 48-1 and 48-2 to detect the infrared eye-tracking beam and infrared imaging light reflected from the first eye 1-1 and the second eye 1-2.

[0059] Many elements of system 10 are included in pairs, such as infrared telescopes 46-1 and 46-2. For the sake of simplicity, such pairs of elements will be referred to only by their leading identifiers, such as “infrared telescope 46” being an abbreviation for “infrared telescopes 46-1 and 46-2”, unless otherwise misunderstood.

[0060] Figure 7 The illustration shows an IR image 49, the result of detection or sensing by the IR camera 48. In this embodiment, there are four IR LEDs 42-1, ..., 42-4 for each eye. To avoid confusion, ... Figure 7 The description omits the "-1" or "-2" indicating a specific eye. Here, the symbols "-1"..."-4" refer to four IR LEDs, all of which project IR eye-tracking beams onto the same eye. The four IR LEDs 42-1, ..., 42-4 project four IR eye-tracking beams onto the eye, which are reflected from the cornea, thus creating four so-called Purkinje field points P1-1, ..., P1-4 in the IR image 49. The symbol "P1" refers to reflections from the proximal surface of the cornea. Higher-index Purkinje field points P2, ... refer to reflections from deeper surfaces within the eye, such as reflections from the proximal and distal surfaces of the cornea. The embodiment described herein utilizes the P1 Purkinje field point, while other embodiments may employ higher-index Purkinje field points.

[0061] The reflected IR imaging light from the IR light source 44 is also detected by the IR camera 48. As shown in the figure, four Purkinje field points P1-1, ..., P1-4 cover the detected reflected IR imaging light, together forming an IR image 49.

[0062] In some embodiments, the eye tracker 40 may include an image recognition system 52 to determine the orientation of the first eye 1-1 and the second eye 1-2 by forming Purkinje field points P1-1, ..., P1-4 using detected infrared eye-tracking beams and forming an IR image 49 using detected infrared imaging light. The image recognition system 52 may use edge recognition methods to extract an image of, for example, the outline of the pupil 3. It may then determine the orientation of the eye 1 from the center of the pupil 3. Additionally, it may determine the orientation of the eye from the Purkinje field points P1-1, ..., P1-4. Finally, it may use various known image recognition and analysis techniques to determine the “optimal” orientation by combining the two determined orientations using a weighted algorithm. The image recognition system 52 may be a separate processor, a separate application-specific integrated circuit (ASIC), or may be implemented as software deployed in a system management computer 50.

[0063] Figures 6A-6B The illustration shows that system 10 may also include infrared-transmitting visible lenses 24-1 and 24-2, one for each eye, to redirect projected visible images 26-1 and 26-2 from stereoscopic display 20 to the first eye 1-1 and the second eye 1-2; and transmit infrared eye-tracking beams and infrared imaging beams 45-1 and 45-2 reflected together from the first eye 1-1 and the second eye 1-2. In these embodiments, stereoscopic display screens 22-1 and 22-2 of stereoscopic display 20 may be positioned peripherally to the main optical path of system 10, and infrared telescopes 46-1 and 46-2 of eye tracker 40 may be positioned within the main optical path of system 10. For reference, in this embodiment, the axis of the adjustable optical lens 34 for each eye—mirror 24—IR telescope 46 is generally referred to as the main optical path. Additionally, for clarity, some labels have been simplified in the diagrams showing optical paths and beams.

[0064] Figure 6B As shown in this embodiment, the peripheral stereoscopic display screens 22-1 and 22-2 can project visible images 26-1 and 26-2 toward the main optical path of system 10. These visible images 26-1 and 26-2 are redirected toward eyes 1-1 and 1-2 by infrared-transmitting visible mirrors 24-1 and 24-2. Simultaneously, reflected IR eye-tracking beams and reflected IR imaging beams 45-1 and 45-2 from eyes 1-1 and 1-2 are transmitted along the main optical path of system 10 toward IR telescopes 46-1 and 46-2 by the same infrared-transmitting visible mirrors 24-1 and 24-2.

[0065] Figure 8A Another embodiment is illustrated in which the positions of the stereoscopic display screen 22 and the IR telescope 46 are interchanged. Figure 8BThe illustration shows that this embodiment may include visible-transmitting infrared (IR) mirrors 24'-1 and 24'-2 to redirect reflected infrared eye-tracking beams and reflected infrared imaging beams 45-1 and 45-2, both reflected from the first eye 1-1 and the second eye 1-2, toward IR telescopes 46-1 and 46-2. Simultaneously, the IR mirrors 24'-1 and 24'-2 can transmit projected visible images 26-1 and 26-2 from the stereoscopic display screens 22-1 and 22-2 of the stereoscopic display 20 to the first eye 1-1 and the second eye 1-2. In these embodiments of system 10, the stereoscopic display 20 may be positioned in the main optical path of system 10, and the infrared telescope 46 of the eye tracker 40 may be positioned peripherally to the main optical path of system 10. For reference, in this embodiment, the axis of the adjustable optical lens 34 for each eye – mirror 24 – stereoscopic display screen 22 is generally referred to as the main optical path in this embodiment.

[0066] Figure 9 The diagram shows... Figures 8A-8B A variant of system 10, wherein the stereoscopic display 20 may include a single stereoscopic display screen 22 and synchronization glasses 28. The synchronization glasses 28 may be shutter glasses or polarized glasses. In this embodiment, Figures 8A-8B The projected visible images 26-1 and 26-2 on the left and right stereoscopic display screens 22-1 and 22-2 are both displayed by a single stereoscopic display screen 22 in a rapidly alternating sequence. Synchronization glasses 28 can be precisely coordinated with this alternating sequence, allowing the visible images 26-1 and 26-2 to be projected onto the first eye 1-1 and the second eye 1-2 in a rapidly alternating manner, thus creating the impression of separate images projected onto these eyes. Synchronization glasses 28 can be similar to 3D glasses used in 3D movie projection and can rely on a circularly polarized liquid crystal LCD layer capable of rapidly changing the polarization of the two lenses of synchronization glasses 28. Such a system 10 can achieve a smaller footprint, which is advantageous. For optimal operation, a sufficiently wide field of view of the stereoscopic display screens 22 can be helpful.

[0067] Some embodiments of system 10 do not require the inclusion of mirror 24 or 24'. In these systems, eye tracker 40 may include a small implementation of IR camera 48 positioned close to the front of system 10 at a sufficiently large angle to prevent IR camera 48 from obstructing projection onto stereoscopic display screen 22. Image recognition system 52 with such an implementation of eye tracker 40 may include a geometric transformation unit to determine the direction of the eye's visual axis from a substantially tilted IR image 49 and Purkinje field points P1, ..., P4 (some points may even be tilted and obscured).

[0068] In an embodiment of system 10, the adjustable optics 30 may include a comprehensive optometry wheel 32-1 and 32-2 having a series of adjustable optical lenses 34-1 and 34-2 with varying optical powers. These adjustable optical lenses 34 are useful for simulating visual distance for the first eye 1-1 and the second eye 1-2.

[0069] As described below with respect to method 100, system 10 can be used to project visible images 26 to a patient at different viewing distances. This can involve at least two technical solutions. First, inserting an adjustable optical lens 34 with variable optical power into the main optical path can create the impression that the projected visible images 26 are farther or closer. Second, projecting visible images 26-1 and 26-2 closer or farther from each other can simulate the appropriate convergence and divergence of these images, another important factor that makes these images appear at the patient's viewing distance.

[0070] In some embodiments, for the first technical solution, the adjustable optical device 30 may include a curved mirror, a test lens, a flip-in / flip-out lens, an adjustable liquid lens, a deformable mirror, a z-axis movable mirror, a rotational diffractive optical element, a translational diffractive optical element, a variable focus moiré lens, or a focusing lens group, which replace or are combined with the phoretic wheel 32.

[0071] Figures 10A-10B The illustration shows that for the second technical solution, the adjustable optics 30 may include a pair of rotatable deflectors 36, a rotatable prism 38, or an adjustable prism 38 (only one is shown) to deflect the projections of images 26-1 and 26-2 to the first eye 1-1 and the second eye 1-2 to simulate the convergence and divergence of the viewing distance for the first eye and the second eye.

[0072] In some embodiments, instead of using the optical elements described above to simulate convergence and divergence, the projections of the projected visible images 26-1 and 26-2 can be shifted toward each other by using stereoscopic display screens 22-1 and 22-2; in other words, they can be projected closer to each other.

[0073] In some systems 10, the adjustable optics 30 and the stereoscopic display 20 can be combined into a single light field display including a microlens array, wherein the projected visible images 26-1 and 26-2 shown on the stereoscopic display screens 22-1 and 22-2, combined with the optical properties of the microlens array, can be used to vary the viewing distance of the projected visible images 26-1 and 26-2 as seen by the patient.

[0074] In some systems 10, the adjustable optics 30 and the stereo display 20 can be combined into a single light field display that includes a microelectromechanical scanner, a focus modulator, or a light source.

[0075] Having described the problem of prismatic or accommodative misalignment and embodiments of system 10 developed to provide progress in the context of misalignment problems, various methods 100 for determining binocular misalignment using embodiments of system 10 will now be described.

[0076] Figures 11-16 The illustration shows a method 100 for determining binocular alignment of eyes 1-1 and eyes 1-2 using the above-described embodiment of system 10.

[0077] Figure 11 Some embodiments of method 100 illustrated may include 120 measuring the unrelated heterophoria of the patient's first eye 1-1 and second eye 1-2 at the visual distance, and 140 determining the accommodative convergence of the first eye 1-1 and second eye 1-2 at the visual distance using the measured unrelated heterophoria. As previously described, method 100 is a two-stage method, and therefore its results integrate the information and knowledge revealed in the two different stages.

[0078] As described in detail below, in some embodiments, measurement 120 may include projecting non-fusionable visible images 26-1 and 26-2 onto a first eye 1-1 and a second eye 1-2 using the stereoscopic display 20 of system 10. For a more concise description of method 100, hereinafter referred to as Figure 5 - The visible images 26-1 and 26-2 in Figure 10 will be referred to simply as images 26-1 and 26-2.

[0079] Examples of projecting non-fusionable images to determine non-associated latent strabismus have been described, for example, regarding Figures 2C-2D In this context, two non-fusionable images 6-1-s and 6-2-s have comparable appearances or dominance. Some embodiments of method 100 also involve projecting such non-fusionable images with comparable dominance.

[0080] In other embodiments, projection may include projecting a dominant image for a first eye 1-1 and a non-dominant image for a second eye 1-2. (See also: Regarding...) Figures 2C-2DThe eye 1-2 that sees the non-dominant image typically begins to wander off after the brain's effort to fuse the two non-fusion images fails. In these embodiments, measurement 120 may include tracking eyes 1-1 and eyes 1-2 using eye tracker 40, and determining when the wandering eye 1-2 finally achieves a relaxed orientation. Achieving this relaxed state may be inferred, for example, by eye tracker 40, by determining that the movement of eye 1-2 slows down below a threshold or changes from directional movement to random jitter or stops. Once eye tracker 40 determines that eye 1-2 has reached a relaxed state, non-associated heterophoria can be measured by measuring the orientation of at least one of the first eye 1-1 and the second eye 1-2 by eye tracker 40.

[0081] Figure 12 The implementation of these steps is described in more detail, and Figures 13A-13D These steps are illustrated in specific embodiments. In these embodiments, measurement 120 may include the following.

[0082] A centered image is projected onto the first eye using a stereoscopic display with the viewing distance convergence and divergence as the primary eye.

[0083] A stereoscopic display is used to project 124 distributed images to the second eye at a viewing distance convergence, where the centered image and the distributed images are non-blending;

[0084] Use an eye tracker to track the rotation of at least one of the 126 first and second eyes;

[0085] Identify 128 relaxation states from the stability of the tracked rotations; and

[0086] 130° of unrelated latent strabismus was measured by measuring the orientation of at least one of the first and second eyes in a relaxed state using an eye tracker and a computer.

[0087] Figure 13A The left panel illustration shows that the projection step 122 of the centered image may include projecting the centered image 201-1 (in this case, a crosshair) onto the stereoscopic display screen 22-1 of the stereoscopic display 20 of the system 10. Projection 122 can be performed with a viewing distance convergence 206. A reference axis 202-1 is introduced as a center normal for reference, connecting the center of the first eye 1-1 to the center of the stereoscopic display screen 22-1. Thus, the viewing distance convergence 206 can be determined by the viewing distance convergence angle. This angle is characterized as the angle between the visual axis 204-1 of the first eye and the reference axis 202-1 when viewing an object positioned at a visual distance L between the two eyes 1-1 and 1-2. More generally, the visual distance convergence 206 will be expressed as, or referred to as, the angle from the center of the first eye 1-1 relative to the reference axis 202-1. The directional line, even if the first eye's visual axis 204-1 does not point along that line.

[0088] The significance of centering the image 201-1 lies in the fact that it is based solely on the convergence and divergence angle of the viewing distance. Off-center from the stereoscopic display screen 22-1 to simulate viewing distance convergence 206. For simplicity, this angle will sometimes be referred to simply as the convergence angle. The definition of the first eye's visual axis 204-1 may include any other relevant portion of the lens or accommodative optics 30-1 through which the first eye 1-1 observes the centered image 201-1.

[0089] Figure 13A The right panel illustrates step 124 of projecting the distributed images for the second eye 1-2, where the distributed images are a set of irregularly placed spheres or spheres of random size and position without a visual center. The centered image 201-1 is an example of the dominant image, while the distributed image 201-2 is an example of a non-dominant image. The centered dominant image 201-1 and the distributed non-dominant image 201-2 are examples of non-fusionable images. Alternatively, similar to... Figure 4C The square frame in the image, the stereoscopic display screen 22-2, can be simply darkened as another embodiment of the non-blending distributed image 201-2, instead of the irregularly placed spheres.

[0090] Figure 13B As illustrated above, the second eye 1-2 will initially rotate inward at approximately the same focal convergence angle as the first eye 1-1. However, after the brain fails to fuse the non-fusionable central image 201-1 and distributed image 201-2, the second eye 1-2 drifts away. The eye tracker 40 can perform tracking step 126 of the second eye 1-2 until the optometrist or automated program determines in step 128 that the drifting second eye 1-2 has reached a relaxed state from the stability of the tracked rotation. This stability can be defined in several ways: from the eye reaching cessation, or the amplitude of eye jitter becoming less than a threshold, or the directional rotation of the eye evolving into non-directional drift.

[0091] In measurement step 130, once the relaxation state has been identified in step 128, the eye tracker 40 can determine the angle between the second eye visual axis 204-2 and the visual convergence divergence 206. To measure the orientation of the relaxed second eye 1-2. In this measurement step 130, the angular deviation of the relaxed second eye 1-2 from the visual distance convergence 206 is measured. This will be referred to as non-associated latent strabismus 208, which has a non-associated latent strabismus angle. This definition is consistent with Figures 4B-4C The definitions are very similar. As mentioned earlier, there are slight differences among practitioners in their definitions of non-associated laticular strabismus.

[0092] In some related embodiments, tracking step 126 may involve tracking the rotation of the first eye 1-1, the second eye 1-2, or both. In these embodiments, the rotation can be measured from the 130-degree lateral angle of the first eye. -1. Second eye perspective -2 and will non-associated latent strabismus Determined as -1 and -2 is used to define non-associated latent strabismus 208 by some type of average value.

[0093] Figures 13A-13B The illustration shows that steps 122-130 of the overall measurement process 120 can be performed for near visual distances, such as L in the range of 40 cm - 100 cm.

[0094] Figures 13C-13D The same steps 122-130 are illustrated and can also be performed as part of a distance vision test, in which case the visual distance L is large and the visual distance convergence angle is [missing information]. =0. In relevant embodiments, L can be in the range of 1 m – 10 m. In diopters, method 100 can be performed at near visual distances corresponding to 1-3 D and at far visual distances corresponding to 0-0.5 D.

[0095] In summary, the result of the first stage measurement step 120 of method 100 is non-associated heterophoria 208, which has a non-associated heterophoric angle. The second phase of Method 100, namely determination step 140, involves performing an additional test for prismatic misalignment based on the newly determined non-associated heterophoria 208. Therefore, Method 100 as a whole is a combination of the first and second phases, thus integrating two distinct tests for prismatic misalignment and consequently incorporating knowledge and data on two different types of binocular alignment. This approach promises to achieve a more thorough treatment and a better improvement in visual acuity.

[0096] Figure 14 The illustration shows that determining step 140 may include a presentation step 142, which uses a stereoscopic display to present a first image for a first eye and a second image for a second eye with the measured non-associated heterophoria correction distance convergence; wherein the first image and the second image are fused.

[0097] Figure 15AThe illustration shows one implementation of presentation step 142, in which a fused first image 210-1 can be presented on a stereoscopic display screen 22-1 for the first eye 1-1, and a fused second image 210-2 can be presented on a stereoscopic display screen 22-2 for the second eye 1-2. These fused images 210-1 and 210-2 can be peripheral. For example, as shown, peripheral images 210-1 and 210-2 can be two substantially identical circular bands or rings of a sphere or planet. The centers of the fused images 210-1 and 210-2 can be shifted toward each other according to the viewing distance convergence angle 206. Non-associated heterophoria as measured in measurement step 120 (208) Correction is performed. As shown in the figure, the measured non-associated latent strabismus It can be symmetrically distributed between the two eyes. In these typical cases, the centers of the fused images 210-1 and 210-2 can be determined based on... The convergence angle is shifted relative to reference axes 202-1 and 202-2 towards each other. Non-associated latent strabismus Correction. In response, the first eye visual axis 204-1 and the second eye visual axis 204-2 are generally aligned with the visual distance convergence 206 corrected by the non-associated heterophoria 208, as indicated by these visual axes 204 pointing to the center of the fusionable image 210.

[0098] In some cases, when the binocular misalignment is asymmetrical, an optometrist may have reason to classify the measured non-associated latent strabismus as a possibility. The distribution is uneven between the two eyes. It should also be noted that earlier conventions continue to make the description easier to understand: where doing so would not cause confusion, the description simply refers to a pair of “restrictions N-1 and restriction N-2” as “restriction N”.

[0099] The shift of the fused image 210 can be affected by the adjustable optics 30. The setting of the adjustable optics 30 can depend on the adjustable distance L or the patient's preferred spectacle power, and may be further corrected by cylinders or aberrations.

[0100] In some embodiments, the first image 210-1 and the second image 210-2 that can be merged can be dynamic. Figure 15A In the diagram, the directional dashed arcs indicate that the planet's rings can rotate around its center. Experiments have shown that rotating the peripheral fusionable images 210 can more reliably and reproducibly capture the peripheral prism effect. In presentation step 142, the radius, spatial distribution, shading, dynamics, and rotation speed of these fusionable images 210 can be adjusted to provide alignment information with optimal weighting.

[0101] In some embodiments, the first image 210-1 and the second image 210-2 may be static. In some embodiments, the first image 210-1 and the second image 210-2 may be centered. These embodiments may demonstrate their own medical advantages.

[0102] Figure 14 Describe and Figure 15B The illustration shows that after presentation step 142, there can be a projection step 144. Projection step 144 may include projecting a first added center image 212-1 onto the first eye 1-1 and a second added center image 212-2 onto the second eye 1-2. These center images 212 may be projected at the center of the fused image 210. In an embodiment where the fused image 210 is a circulating planet, the added center images 212 may be projected at the center of its circulation, for example, a cross as shown.

[0103] The projections 144 of these two added center images 212-1 and 212-2 can be performed alternately using a stereoscopic display 20. To illustrate the alternating manner of the projections 144, in... Figure 15B In the diagram, only one of the added center images, cross 212-1, is shown as a solid line, while the other added center image, 212-2, is shown as a dashed line. The alternation period can be selected according to several different criteria and can be less than 1 second, ranging from 1 second to 100 seconds, and in some cases from 5 seconds to 10 seconds.

[0104] If measured in step 120 If the angle of non-associated heterophoria 208 completely captures the binocular alignment of eye 1, then eye 1 will not need to adjust to have the angle of non-associated heterophoria. / 2 Corrected convergence angle The projection step 144 involves adding a central image 212. This in itself implies that the eye's visual axis 204 will remain aligned with the non-associated psilocytic viewpoint after projection step 144. / 2 Corrected convergence angle alignment.

[0105] However, the applicant's research shows that patients respond to a corrected convergence angle. The added central image 212 is projected onto the projection 144, and the eyes 1 are moved and adjusted. This makes the applicant realize that additional measurements must be performed to determine the remaining, residual prismatic misalignment of the eyes. These additional measurements are described below in steps 146-154.

[0106] Using an eye tracker, the adjustment of the first eye in response to the projection of the first added central image is tracked, and the adjustment of the second eye in response to the projection of the second added central image is tracked.

[0107] Using a stereoscopic display and a computer, in an alternating manner, projection 148 uses a first added central image of a first iterative associated heterophoric shift to reduce the adjustment of the first eye, and projects a second added central image of a second iterative associated heterophoric shift to reduce the adjustment of the second eye.

[0108] The eye tracker tracks the adjustment of the first eye in response to the projection of a first added center image with shift, and the adjustment of the second eye in response to the projection of a second added center image with shift;

[0109] Determine whether the effective adjustment of the first eye and the second eye is less than the adjustment threshold, and if the effective adjustment of the first eye and the second eye is greater than the adjustment threshold, then return to the step of the first added center image of the projection shift;

[0110] If the effective adjustment of the first and second eyes is less than the adjustment threshold, then 154 stable correlated heterophoria are identified from the last first-iteration correlated heterophoria and the last second-iteration correlated heterophoria; and

[0111] The sum of 156 non-associated heterophoria and stable associative heterophoria is identified as a correction for accommodative convergence corresponding to the visual distance. These steps will be described in detail below.

[0112] Figure 14 Describe and Figure 15B As illustrated, in order to determine residual prismatic misalignment, after projection step 144, eye tracker 40 may be used to track 146 the adjustment of the first eye 1-1 in response to the projection of the first added center image 212-1 and the adjustment of the second eye 1-2 in response to the projection of the second added center image 212-2. Figure 15B The illustration shows that the first eye 1-1 is adjusted to the projection 144 by rotating the first eye's visual axis 204-1 by an adjustment angle 214-1 (denoted by ε-1), and the second eye 1-2 is adjusted by rotating the second eye's visual axis 204-2 by an adjustment angle 214-2 (denoted by ε-2). From now on, for simplicity, these angles will refer to angles corrected by non-associated heterophoria. The line-of-sight convergence and divergence, rather than the reference axis 202. The fact that the adjustment angles ε-1 and ε-2 are non-zero makes it necessary to determine the subsequent steps of step 140.

[0113] Figure 15CAs shown, determining the accommodative convergence step 140 then includes projection 148 to the first iterative correlation of latent strabismus. The first added center image 212-1 is shifted to reduce the adjustment of the first eye 1-1, and the projection is used to correlate the second iteration of latent strabismus. The second added center image 212-2 is shifted to reduce the adjustment of the second eye 1-2. As explained in detail below, the eye adjustment here can be achieved by adjusting the angle. The changes were measured.

[0114] For the sake of clarity and brevity, in this Figure 15C In the diagram, only the first eye 1-1 is explicitly shown. A shifted, added central image 212 is attached to the eye 1 and is characterized by the shifted image axis 216. Figure 15C The first shifted image axis 216-1 is shown, which connects the first added center image 212-1 to the first eye 1-1.

[0115] Regarding Figure 2- Figure 3 The description refers to the related latent strabismus that requires compensation. and gaze differences They are not simply equal and opposites. Similar to this identification, associative latent strabismus... It's not simply about adjusting the angle with the first eye. They are equal and opposite. Therefore, embodiments of method 100 iteratively determine these quantities in steps 1, 2, ..., n. In the definitions above, the step index is shown as... and The first iteration of correlational latent strabismus is used. Representation, first and second iteration correlation of latent strabismus This means that, and so on. Naturally, the indices “-1” and “-2” continue to mark the corners of the first eye 1-1 and the second eye 1-2 respectively, while the indices “(1)”, “(2)”, ..., “(n)” mark the first, second and nth steps of the iterative process.

[0116] As in projection step 144, the projection of these shifted added central images 212-1 and 212-2 can be performed in an alternating manner using stereoscopic display 20 and computer 50 148.

[0117] Figure 15CThe illustration also shows that after projection step 148, the eye tracker 40 can be used to track 150 the adjustment of the first eye 1-1 in response to the projection of the first added center image 212-1 with displacement, and to track the adjustment of the second eye 1-2 in response to the projection of the second added center image 212-2 with displacement. Only the presentation of the first eye 1-1 is illustrated; tracking step 150 includes tracking the adjustment in response to the projection of the first added center image 212-2 with displacement. The first added center image 212-1 of the shifted projection 148 first eye 1-1 adjustment angle .

[0118] This tracking step 150 is similar to tracking step 146. The difference is that the iteration step index grows from (n) to (n+1). In short, embodiments of the method involve iteratively shifting the added center image 212 to correlated latent strabismus. Tracking the responsive adjustment angle of eye 1 From the change of adjustment angle Determine the adjustment of eye 1, and then use the new iteration's correlational latent strabismus. (Choose to reduce the change in adjustment angle) (Amplitude and sign) Repeat the shift of the added center image 212.

[0119] In some embodiments, The amplitude can be chosen to be equal to In some cases, these embodiments may exhibit slow convergence. Therefore, in some embodiments, Can be selected equal to , where λ < 1. These embodiments typically exhibit good convergence. Other nonlinear, polynomial, nonanalytic, or analytic relationships may also be employed in various embodiments.

[0120] After iteratively performing steps 148 and 150, step 152 can be performed to determine whether the effective adjustment of the first and second eyes is less than an adjustment threshold. Using the above framework, step 152 can evaluate the change in the adjustment angle. Is it less than a threshold? Effective adjustment can be defined in several ways. It might involve a change in the adjustment angle of only one eye: for eye 1-1 is... ; or the sum of the changes in the adjustment angles of the two eyes 1-1 and 1-2, or some weighted average, or a non-linear relationship.

[0121] like Figure 15C As shown, if the adjustment angle changes If the value is greater than the threshold, then the method can return to the projection step 148 of the first added center image 212 of the shift.

[0122] On the other hand, if a change in the angle is found, for example, in step (n), If the adjustment of the represented eye is less than the threshold, then the iteration can stop, and the method can continue from the last first iteration of the associated latent strabismus. Related to the last second iteration of latent strabismus Identify 154 stable associative latent strabismus Furthermore, different formulas can be used to define stable associative latent strabismus in step 154. ,For example, .

[0123] In the foregoing embodiments, non-associated latent strabismus and stable correlation with latent strabismus It is usually defined for both eyes together. Therefore, in the case of symmetry, the value for each eye is half of the angle defined here.

[0124] After identifying step 154, non-associated latent strabismus can be identified. and stable correlation with latent strabismus The sum Identify 156 as a correction for the accommodative convergence AC, which has an accommodative convergence angle corresponding to the viewing distance. Thus, using the prism's refractive power... The form, whereby the fully or fully corrected accommodative convergence determined by method 100, can be obtained via the corresponding fully or fully corrected accommodative convergence angle. Expressed using the tangent. As mentioned earlier, the typical definition of regulated convergence is... prism diopter The unit is [unit missing]. This form illustrates that the results of an embodiment of method 100 represent a significant improvement over previous methods, which only used non-associated latent strabismus. To correct , converted Another difference compared to previous methods is the determination... The specific system 10 and method 100.

[0125] Having determined the fully corrected AC by method 100, binocular alignment can again be characterized by the AC / A ratio, the ratio of accommodative convergence AC to accommodative response A. This AC / A ratio can be determined for a single distance, or it can be derived from the AC and A values ​​for multiple distances. For simplicity, from now on, the fully corrected accommodative convergence AC will be simply referred to as accommodative convergence AC.

[0126] In some embodiments, method 100 may include using distance vision accommodative convergence AC (L) d ) is determined to be at the distance of distance vision L d Accommodative convergence resulting from the execution of method 100; and near-visual accommodative convergence AC (L n ) was determined to be at the near visual distance L n The regulatory convergence resulting from the execution method.

[0127] Through this preparation, in some embodiments, binocular alignment of the first and second eyes can be characterized by first determining the distance visual accommodative response A(L) in diopters. d ) and near visual accommodation response A (L n Then, by constructing a distance vision accommodative convergence AC (L) d Subtract near vision accommodative convergence AC (L) d ) divided by the distance vision accommodation response A (L d Subtract the near visual accommodation response A (L) n The ratio of the first and second eyes is used to characterize binocular alignment:

[0128] Eyes aligned = (1)

[0129] In some embodiments, the adjustable optics 30 may be used to perform the measurement 120 at the line of sight and the determination 140 at the line of sight.

[0130] When the shortcomings of existing methods were previously described, the subjectivity of patient feedback was identified as a source of dispersion in the data and a cause of limited reproducibility. In this case, it should be mentioned that embodiments of method 100 can be performed without soliciting substantial responses from the patient to determine one of the key quantities or angles. (Of course, non-substantial responses regarding, for example, comfort are likely part of method 100.) This is one of the key reasons why method 100 provides measurements with high reproducibility.

[0131] Figure 16 The illustration shows that, in some embodiments, when method 100 is performed at a viewing distance corresponding to near vision, non-associated heterophoria and accommodative convergence corresponding to near vision can be determined from a viewing angle below the equatorial direction 9 by displaying a centered image 201 below the equatorial direction 9.

[0132] The applicant’s extensive experiments have shown that when prism glasses are manufactured based on the accommodative convergence determined by method 100, patients wearing these glasses have reported particularly promising reductions in visual discomfort, pain, and migraines associated with digital devices.

[0133] It is very likely that this substantial improvement has already been achieved, as method 100 has developed and integrated solutions regarding the previously identified points (1)-(5), as described below.

[0134] (1) Method 100 does not use the patient’s subjective response as a key input.

[0135] (2) Method 100 uses two peripheral images (e.g., images 124 and 210) and a central image (e.g., images 201 and 212).

[0136] (3) Method 100 uses a two-stage approach with a measurement step 120 and a determination step 140 to collect and utilize information about both central vision and peripheral vision.

[0137] (4) Method 100 uses a moving test image, such as image 210.

[0138] (5) Method 100 developed a specific definition of accommodative convergence and its established protocol, for example in steps 142-156, and demonstrated through extensive testing that eyeglasses prescribed using this definition are particularly effective in reducing discomfort associated with eye fatigue.

[0139] For all these reasons, the aforementioned system 10 and method 100 offer promising new ways to reduce discomfort, pain, and migraines associated with eye strain.

[0140] Figures 17-25 An additional embodiment of the system 310 for determining eye alignment is illustrated, showing a comparison with... Figures 8A-8B The similarities between the embodiments of system 10 for determining binocular alignment and the present invention are as follows. Therefore, similar parts are labeled with the same tags, using 300 as the base. As an example, system 310 for determining binocular alignment can be considered an embodiment of system 10 for determining binocular alignment; therefore, the various elements and techniques described with respect to system 10 can be applied to, adapted to, and combined with elements and techniques of system 310, and vice versa. For brevity, system 310 for determining binocular alignment will sometimes be simply referred to as system 310.

[0141] Figure 17The diagram illustrates a system 310 for determining binocular alignment. The system includes: a first optical unit 315-1 comprising a first display 322-1 and a first eye tracker assembly 340-1. The first display 322-1 displays an image for a first eye 1-1 and is actuated longitudinally according to an analog distance and the optical power of the first eye 1-1. The first eye tracker assembly 340-1 tracks the gaze direction of the first eye 1-1 and is adjustable in the horizontal direction to accommodate a first interpupillary distance 4-1 of the first eye; and a second optical unit 315-2 comprising a second display 315-1. The second eye 1-2 and the second eye tracker assembly 340-2, the second display 322-2 for displaying images for the second eye 1-2 and actuated in the longitudinal direction according to the simulated distance and the optical power of the second eye 1-2, the second eye tracker assembly 340-2 for tracking the gaze direction of the second eye 1-2 and adjustable in the horizontal direction to adapt to the interpupillary distance 4-2 of the second eye 1-2; and the computer 350, which is coupled to the first optical unit 315-1 and the second optical unit 315-2 for determining binocular alignment based on the gaze direction of the first eye 1-1 and the second eye 1-2. Figure 17 The xyz coordinate system, an alternative method for characterizing direction, is also shown on the side. Using this xyz coordinate system, the "horizontal lateral direction" is aligned with the x-axis, the "vertical lateral direction" with the y-axis, and the "vertical direction" with the z-axis. This alignment can be strict, or in some embodiments it can be within tolerances (such as ±10 degrees).

[0142] Different patients have different prescriptions, such as myopia or hyperopia of a few diopters. Some previously described embodiments of the system 10 used to determine binocular alignment use phoropter wheels 32-1 and 32-2 with lenses of different diopters to simulate these prescriptions, while displaying images to the patient on fixed stereoscopic display screens 22-1 and 22-2—see, for example… Figures 8A-8B These embodiments measure binocular alignment at two different nominal distances. These distances are again simulated by rotating the phoropter wheels 32-1 and 32-2 and engaging lenses with refractive powers representing simulated distances other than the patient's prescription.

[0143] Embodiments of the system 310 for determining binocular alignment do not involve the phoropter wheels 32-1 and 32-2: these perform the aforementioned two functions by enabling displays 322-1 and 322-2 to actuate longitudinally according to simulated distances and the optical powers of eyes 1-1 and 1-2. The elimination of the phoropter wheels 32-1 and 32-2 makes the physical size of the system 310 for determining binocular alignment significantly smaller than that of the system 10 for determining binocular alignment using the phoropter wheels 32-1 and 32-2. This is an advantage in the crowded offices of optometrists where physical space is scarce. Furthermore, the use of the phoropter wheels 32-1 and 32-2 allows the system 10 for determining binocular alignment to simulate the patient's prescription using only step sizes, such as 1 diopter. As another advantage, the system 310 for determining eye alignment can actuate the first display 322-1 and the second display 322-2 substantially continuously along the longitudinal direction, thus continuously simulating the patient's prescription with high accuracy (possibly within 0.1 diopters or better).

[0144] Another challenge with the system 10 designed using the phoropter wheel 32-1 is that when the phoropter wheel 32-1 is rotated to engage a new lens to simulate a new distance or prescription, the magnification changes with the rotation of the phoropter wheel 32-1 because the first eye tracker assembly 340-1 is observing the eye 1-1 through the lens of the phoropter wheel 32-1. This change in magnification necessitates recalibrating the image analysis performed by the computer 350. This recalibration can lead to time lags and potential coding challenges. In contrast, embodiments of the system 310 for determining binocular alignment using an actuable first display 322-1 and a second display 322-2 avoid this need for recalibration, making the operation of the system 310 much easier.

[0145] In some embodiments, the first display 322-1 and the second display 322-2 can travel in a longitudinal range of 50 mm to 200 mm (in some embodiments, in a range of 75 mm to 125 mm). The nearest longitudinal distance between the first display 322-1 and the second display 322-2 and the first eye tracker assembly 340-1 and the second eye tracker assembly 340-2 can be in the range of 5 mm to 40 mm, and in other embodiments, in the range of 10 mm to 30 mm. Thus, in some embodiments, the system 310 for determining binocular alignment can simulate a prescription power of -20 D to +20 D or less, in other embodiments in the range of -10 D to +10 D or less, and in still other embodiments in an asymmetric range, such as -10 D to +20 D or less.

[0146] In this embodiment, the closer the first display 322-1 and the second display 322-2 are positioned to the eyes 1-1 and 1-2, the larger the field of vision perceived by the patient. This field of vision can extend at least from -30 degrees to +30 degrees, and in other embodiments at least from -35 degrees to +35 degrees, or even larger values. Therefore, some embodiments of the system 310 used to determine binocular alignment can also be used for visual field testing with multiple purposes, such as identifying local blind spots or scotomas, and peripheral visual problems. These symptoms can indicate various diseases, such as glaucoma or brain disorders.

[0147] Making at least a portion of the first optical unit 315-1 and the second optical unit 315-2 adjustable in the lateral direction has several advantages, and several embodiments achieve this adjustability. As described above, by making the first eye tracker assembly 340-1 and the second eye tracker assembly 340-2 adjustable in the horizontal lateral "x" direction, it is possible to accommodate different interpupillary distances for different patients. Furthermore, in a system where the first optical unit 315-1 and the second optical unit 315-2 are fixed, when the patient is prompted to look at a simulated near object, the eye is looking through the system's front lens (see, for example, the first lens assembly 360-1 in Figure 18) through a nasally offset off-center region. While these front lenses provide the designed refractive power, their off-center regions also introduce unintended prisms into the refraction of light, which disrupts the correct determination of the patient's binocular alignment. Embodiments of the system 310 for determining binocular alignment again minimize or even eliminate this problem by making the first eye tracker assembly 340-1 and the second eye tracker assembly 340-2, along with their corresponding front lenses, actuable in the horizontal lateral direction. In these systems 310, when simulating a closer object by displaying an image of the first eye 1-1 and the second eye 1-2 shifted near the center of system 310, the first eye tracker assembly 340-1 and the second eye tracker assembly 340-2, together with their front lenses, can be horizontally actuated so that the patient still looks at the closer object through the center of the system's front lens to determine eye alignment 310, thereby avoiding unintended prismatic effects.

[0148] The motivation for introducing horizontal lateral adjustability described above can be achieved not only by making the first eye tracker assembly 340-1 and the second eye tracker assembly 340-2 adjustable or actuable in the horizontal lateral direction. First, as mentioned earlier, the first eye tracker assembly 340-1 and the second eye tracker assembly 340-2 can be adjusted together with their corresponding front lenses. Furthermore, in some embodiments of the system 310 for determining binocular alignment, the first display 322-1 can also be structurally adjustable or actuable together with the first eye tracker assembly 340-1; and the second display 322-2 can also be structurally adjustable or actuable together with the second eye tracker assembly 340-2. For example... Figure 17 As shown, when the adjustability of the front lens is also taken into account, in these embodiments, the entire first optical unit 315-1 and the second optical unit 315-2 can be horizontally adjustable or actuated.

[0149] Another type of adjustability is also useful. It is noteworthy that there is a significant distribution in the population regarding the vertical position of the left and right eyes: the two eyes are often misaligned by several millimeters in the vertical direction. Such patients may encounter problems when aligning their eyes with the first optical unit 315-1 and the second optical unit 315-2. Embodiments of the system 310 for determining binocular alignment address this problem by making the first eye tracker assembly 340-1 adjustable with its front lens in the vertical-lateral direction; and making the second eye tracker assembly 340-2 adjustable with its front lens in the vertical-lateral direction. In the language of the previously defined coordinate system, this translates to adjustability along the y-axis.

[0150] Figure 18AThe illustration shows some embodiments of the system 310 for determining binocular alignment. Within the first optical unit 315-1, a first eye tracker assembly 340-1 may include one or more first infrared light-emitting diodes (IR LEDs) 342-1 to project an infrared eye-tracking beam 342b-1 onto the first eye 1-1. Furthermore, the first eye tracker assembly 340-1 may also include a first infrared (IR) light source 344-1 to illuminate the first eye 1-1 with infrared imaging light 344b-1. Finally, the first eye tracker assembly 340-1 may include a first infrared camera 348-1 to detect the infrared eye-tracking beam and the infrared imaging light, both reflected from the first eye 1-1, collectively labeled 345b-1, via a first IR optics 346-1. Naturally, in the system 310 for determining eye alignment, within the second optical unit 315-2, the second eye tracker assembly 340-2 may include: one or more second infrared light-emitting diodes 342-2 for projecting an infrared eye-tracking beam 342b-2 onto the second eye 1-2; a second infrared light source 344-2 for illuminating the second eye 1-2 with infrared imaging light 344b-2; and a second infrared camera 348-2 for detecting the infrared eye-tracking beam and the infrared imaging light, both reflected from the second eye 1-2, via a second IR optics 346-2, collectively labeled 345b-2. Since the second eye tracker assembly 340-2 is similar to the first eye tracker assembly 340-1, it need not be explicitly shown. For orientation, Figure 17 The xyz coordinate system is also displayed, and its viewpoint is relative to... Figure 17 The perspective rotates.

[0151] In embodiments, the number of the first IR LED 342-1 and the second IR LED 342-2 can range from 1 to 10, and in some embodiments from 2 to 4. In embodiments, the first infrared light source 344-1 can include a spatially distributed set of individual infrared LEDs to illuminate the first eye 1-1 with dispersed infrared imaging light 344b-1; and the second infrared light source 344-2 can include a spatially distributed set of individual infrared LEDs to illuminate the second eye 1-2 with dispersed infrared imaging light 344b-2. The individual infrared LEDs of the first infrared light source 344-1 and the second infrared light source 344-2 can be positioned in many different patterns, such as circles, arcs, rectangles, and rectangular arrays, etc. Their number can range from 1 to 50, and in some embodiments from 5 to 20. The infrared imaging light 344b-1 and 344b-2 can be dispersed or homogenized in different ways (including through a diffuser, or through a scattering mirror, or through a scattering surface).

[0152] Figures 18A-18BThe illustration shows one or more first infrared light-emitting diodes 342-1 that can be positioned at different locations within the first eye tracker assembly 340-1. Figure 18A In this design, the first infrared light-emitting diode 342-1 is positioned in the front region of the first eye tracker assembly 340-1, close to the first eye 1-1. In these designs, the IR beam 342b-1 can form a large angle with the principal optical axis of the first optical unit 315-1, potentially complicating the centering of the reflected IR light. Figure 18B In this configuration, one or more first infrared light-emitting diodes 342-1 are positioned much higher upstream along the optical path, near the first infrared camera 348-1, typically close to its center, the first IR optics 346-1. In these designs, the IR beam 342b-1 can be well aligned with the principal optical axis of the first optical unit 315-1.

[0153] In some embodiments of the system 310 for determining binocular alignment, the computer 350 may include an image analysis system 352 or be connected to the image analysis system 352 to determine the orientation of the first eye 1-1 and the second eye 1-2 using reflections of infrared eye-tracking beams 342b-1 and 342b-2, commonly labeled 345b-1 and 345b-2, and an IR image formed by infrared imaging beams 344b-1 and 344b-2. The image analysis system 352 may be configured to determine Purkinje reflections from the first eye 1-1 and the second eye 1-2 using the detected reflected infrared eye-tracking beams 342b-1 and 342b-2; and to determine pupillary properties of the first eye 1-1 and the second eye 1-2 using the IR image formed by infrared imaging beams 344b-1 and 344b-2. Purkinje reflections may be any of the so-called P1, P2, etc., Purkinje reflections, labeled according to the optical surface of the eye from which they reflect. One commonly used Purkinje reflection is P1, which is a reflection from the anterior surface of the cornea. The IR beam 342b-1 is typically guided by the first IR LED 342-1 to reflect off the apex of the cornea to produce a central P1 Purkinje reflection. Determining the gaze direction may also involve determining one of the pupil properties, such as the location of the pupil center or the degree of ellipticity of the pupil image. For a typical eye, the pupil of eye 1-1 will appear as a circle when the eye's optical axis is aligned with the principal optical axis of the first eye tracker assembly 340-1. When the gaze direction of eye 1-1 is rotated away from this principal optical axis by an angle of rotation, the same pupil will appear as an ellipse. Analyzing the ellipticity of this ellipse (e.g., given by the ratio of its minor axis to its major axis) and determining the orientation of these axes provides important information about the angle of rotation regarding the gaze direction. Other pupil properties may also involve the imaging of the iris and the recording of specific features of the iris. Determining pupil properties may involve edge recognition software that identifies the precise edges of the pupil.

[0154] The operation of these first optical units 315-1 and second optical units 315-2, as well as the image analysis system 352, has been designed through recall of numerous patients with varying pupil sizes who are not perfectly circular or perfectly aligned. For example, in patients whose eyes are not perfectly aligned, when one eye is aligned with the optical axis of its corresponding eye tracker assembly 340-1 or 340-2, the other eye is not aligned with its corresponding eye tracker optical axis. Finally, the Purkinje reflex may not originate precisely from the vertex.

[0155] To determine the gaze direction of the first eye 1-1 and the second eye 1-2 despite all these possible deviations from ideal conditions, the image analysis system 352 typically operates by first instructing the patient to look straight ahead, then registering and recording the position of the Purkinje reflex P1 and the pupillary center using the first IR camera 348-1 and the second IR camera 348-2. Additionally, the ellipticity of the eyes and other pupillary properties can also be recorded. Connecting the position of the Purkinje reflex P1 with the pupillary center can be used to define the gaze direction or the direction of the eye's optical axis. All these records are used as reference directions for subsequent measurements. Following this reference setting step, visible images 326-1 and 326-2 may be projected onto the patient via a first display 322-1 and a second display 322-2. Simultaneously, in response to these images, one or more Purkinje reflexes, pupillary center, and other pupillary attributes such as ellipticity are remeasured. The Purkinje reflexes, pupillary center, and pupillary attributes of the first eye 1-1 and the second eye 1-2 are then compared with previously determined reference Purkinje reflexes, pupillary center, and pupillary attributes of the first eye 1-2 and the second eye 1-2. As described below, comparing these measured values ​​with reference values ​​can then be used to determine the gaze direction and its changes.

[0156] In an embodiment, the image analysis system 352 can use the position of the pupil center in the xy plane (as determined by the IR image formed by reflected IR beams 344b-1 and 344b-2) and the position of the Purkinje reflection P1 from the apex of the cornea (as determined by reflected IR beams 342b-1 and 342b-2). If the pupil center and the corneal apex overlap or coincide in the xy plane, then the eye is looking forward, as in the reference IR image. When the pupil center and the corneal apex are offset in the xy plane, the image analysis system 352 can determine the rotation angle of the gaze direction of each eye relative to the reference direction from the direction and magnitude of the offset.

[0157] As previously mentioned, for some patients, even when they are looking straight ahead, the pupil center and corneal apex may not coincide in the reference image. However, even in these cases, the image analysis system 352 can acquire the positions of the pupil center and corneal apex in an image of the rotated eye, then subtract the reference positions from these positions, and determine the rotation angle of the gaze direction of eyes 1-1 and 1-2 in response to the projected visible images 326-1 and 326-2 from the difference thus constructed. Other embodiments may determine the gaze direction using other methods, such as other pupillary properties and / or other Purkinje reflexes. Other embodiments may use multiple pupillary properties without using Purkinje reflexes. Other embodiments may proceed in reverse: using multiple Purkinje reflexes without using pupillary properties.

[0158] Because the eye performs multiple rapid eye saccades per second, the gaze direction changes rapidly over time. Therefore, if measured close together in time, the Purkinje reflex and pupillary center, along with other possible pupillary properties, indicate a specific gaze direction. Conversely, if they are measured with a large time difference (greater than 0.1 seconds or 1 second or more), the gaze direction calculated by the image analysis system 352 may become increasingly inaccurate. To improve the accuracy of this calculation, in some embodiments, one or more first infrared LEDs 342-1 project an infrared eye-tracking beam (IR beam) 342b-1 alternately with illumination from a first infrared light source 344-1 using infrared imaging light 344b-1; and one or more second infrared LEDs 342-2 project an infrared eye-tracking beam 342b-2 alternately with illumination from a second infrared light source 344-2 using infrared imaging light 344b-2. The alternation frequency can be in the range of 1 Hz – 1000 Hz, in some embodiments in the range of 10 Hz – 150 Hz, and in some embodiments in the range of 60 Hz – 120 Hz. Through these alternations, the first IR camera 348-1 and the second IR camera 348-2 can determine the Purkinje reflex and pupil center, and possibly other pupillary properties, within 1 ms – 1000 ms in other embodiments, and within 8 ms – 16 ms in still other embodiments. Determining the Purkinje reflex and pupil center, and possibly other pupillary properties, so closely relative to each other, advantageously improves the accuracy of the image analysis system 352 in calculating the gaze direction. As previously mentioned, in some embodiments of the system 310 used to determine binocular alignment, only a plurality of pupillary properties are determined, and in other embodiments of the system 310, only a plurality of Purkinje reflexes are determined. Determining any of these at the aforementioned repetition rate also improves the accuracy of gaze direction determination.

[0159] In some embodiments of the system 310 for determining binocular alignment, the first eye tracker assembly 340-1 further includes a first visible-transmitting infrared mirror 324-1, which is positioned to transmit an image from the first display 322-1 to the first eye 1-1 in a longitudinal direction; and to redirect reflected infrared eye-tracking beams and infrared imaging beams (collectively 345b-1) from the first eye 1-1 in a lateral direction to the first infrared camera 348-1; and the second eye tracker assembly 340-2 includes a second visible-transmitting infrared mirror 324-2, which is positioned to transmit an image from the second display 322-2 to the second eye 1-2 in a longitudinal direction; and to redirect reflected infrared eye-tracking beams and infrared imaging beams (collectively 345b-2) from the second eye 1-2 in a lateral direction to the second infrared camera 348-2. In some embodiments, a first infrared camera 348-1 is positioned relative to a first visible-transmitting infrared mirror 324-1 in one of a vertical lateral direction or a horizontal lateral direction; and a second infrared camera 348-2 is positioned relative to a second visible-transmitting infrared mirror 324-2 in one of a vertical lateral direction or a horizontal lateral direction. The horizontal lateral direction corresponds to the x-axis, and the vertical lateral direction corresponds to... Figure 17 - The y-axis of the xyz coordinate system in Figure 18.

[0160] Various eye-tracking display systems are available, such as those in virtual reality goggles, where the IR eye-tracking beam and the projected visible image do not share a common optical path and they do not utilize visible transparent IR mirrors. In these designs, the eye tracker's IR camera is pointed directly at the eye. However, the geometry of this design dictates that these IR cameras point at the eye from a high angle. Thus, the eye-tracking IR beam is often obstructed by long eyelashes, which confuses their image analysis system and can lead to tracking deadlock. In the current system 310 used to determine eye alignment, this obstruction problem due to eyelashes is avoided by having the reflected IR beam and the IR imaging beams 345b-1 and 345b-2 share a main optical path (leaving the eye in the normal / z / longitudinal direction and then being redirected by the first visible transparent IR mirror 324-1 and the second visible transparent IR mirror 324-2).

[0161] As previously described, when measuring binocular alignment, the first display 322-1 can be actuated to a first longitudinal position based on the simulated distance, wherein the first longitudinal position is dynamically corrected according to the optical power of the first eye 1-1; and the second display 322-2 can be actuated to a second longitudinal position based on the simulated distance, wherein the second longitudinal position is dynamically corrected according to the optical power of the second eye 1-2. The first display 322-1 and the second display 322-2 can be continuously actuated along the longitudinal / z-direction, which allows for more precise correction of the simulated distance based on the optical power or prescription of the patient's eyes 1-1 and 1-2. It is also worth noting that many virtual reality displays achieve cost advantages by using a single display and displaying images for the left and right eyes on corresponding halves of that single display. However, such systems lack the degrees of freedom to move the two halves of the display to different z-coordinates, even though for most people their two eyes have different prescriptions and therefore require different z-coordinates. In contrast, since the two displays 322-1 and 322-2 are independently actuable, embodiments of the system 310 for determining binocular alignment are well-suited to handling such different prescriptions.

[0162] Furthermore, when simulating images at different distances to determine binocular misalignment at these distances, the horizontal position of the image can be moved accordingly by the computer 350 on the first display 322-1 and the second display 322-2.

[0163] Figures 18A-18B The illustration also shows that the first optical unit 315-1 may include a first lens assembly 360-1 to receive and guide an infrared eye-tracking beam and an infrared imaging beam, both reflected from the first eye and collectively labeled 345b-1, toward the first infrared camera 348-1, and to reduce at least one of chromatic aberration, optical aberration, optical astigmatism, and wavefront distortion; and the second optical unit 315-2 may include a second lens assembly 360-2 to receive and guide an infrared eye-tracking beam and an infrared imaging beam, both reflected from the first eye and collectively labeled 345b-2, toward the first infrared camera 348-2, and to reduce at least one of chromatic aberration, optical aberration, optical astigmatism, and wavefront distortion. (For simplicity, the elements of the second optical unit 315-2 are not explicitly shown—they are similar to the elements of the first optical unit 315-1.)

[0164] In some embodiments of the system 310 used to determine binocular alignment, the first infrared camera 348-1 and the first lens assembly 360-1 are adjustable together; and the second infrared camera 348-2 and the second lens assembly 360-2 are also adjustable together. In embodiments where the two components are not adjustable together, the infrared cameras 348-1 and 348-2 need to be much larger so that high resolution and low distortion of the image can be maintained even if the first lens assembly 360-1 and the second lens assembly 360-2 are adjusted to an off-center, misaligned position. Conversely, in embodiments where the first and second infrared cameras 348-1 and 360-2 are adjustable together with the first infrared camera 348-1 and the second infrared camera 348-2, the first and second infrared cameras 348-1 and 348-2 can be made much smaller because collinearity with the first and second lens assemblies 360-1 and 360-2 is maintained despite adjustments. The smaller size of the first infrared camera 348-1 and the second infrared camera 348-2 advantageously reduces the overall size of the system 310 used to determine eye alignment.

[0165] Figure 19 An embodiment of a system 310 for determining eye alignment is illustrated. It shows a connection with... Figure 17 - The same element as in Figure 18, viewed from the top, y-direction, or downward in the vertical and horizontal direction, is similar. Figure 17 Specifically, it clearly demonstrates the direction of actuation in the longitudinal / z-direction and the horizontal / x-direction.

[0166] Figure 20 An embodiment of the first optical unit 315-1 of the system 310 for determining binocular alignment is illustrated in the perspective view. In addition to the previously described elements, further elements can be seen, including a first z-actuator 347-1 configured to actuate the first display 322-1 along the longitudinal / z-direction. Furthermore, a first coupling 354-1 to the computer 350 is also visible, which couples the first display 322-1 to the computer 350 using a set of flexible or deformable communication lines. The first display 322-1 can be configured such that the first eye 1-1 displays an image modified according to at least one of the optical power, lenticular lens, and prism of the first eye 1-1; and the second display 322-2 can be configured such that the second eye 1-2 displays an image modified according to at least one of the optical power, lenticular lens, and prism of the second eye 1-2.

[0167] In some embodiments, the first display 322-1 and the second display 322-2 may include a liquid crystal display, a light-emitting diode (LED) display, an organic LED display, a quantum dot LED display, a microlens array, a digital mirror device, and a scanning projector microelectromechanical system.

[0168] Figure 21The illustration shows a frontal, z-direction view of the system 310 used to determine eye alignment. This is what the patient can see. A first lens assembly 360-1 and a second lens assembly 360-2 are shown. In addition, some embodiments include a nasal bridge 370, centrally located between the first optical unit 315-1 and the second optical unit 315-2, configured to receive and secure the patient's nose.

[0169] This embodiment offers an improvement over related diagnostic systems. Many related diagnostic systems aim to stabilize the patient's head and eyes using variations of a chin rest where the patient places their chin. However, the chin still acts as a rotational axis of the patient's head, so the eyes can still rotate around the supported chin with the distance from the chin to the eye as the radius, resulting in rotational misalignment with the diagnostic device. By stabilizing the patient's head and eyes at the nose rather than the chin, this residual rotational misalignment can be minimized or eliminated. The nose bridge 370 achieves this with its "downward V" shape: it stabilizes the patient's head at the top of the nose (very close to the eyes) rather than at the chin. For this reason, in such an embodiment, the eyes are much more securely fixed relative to the system 310 used to determine eye alignment.

[0170] Another advantage is... Figures 17-21 Proof. Let the center of the system 310 used to determine binocular alignment be denoted as center 311. For a subset of patients, the distances from the pupil center of their first eye 1-1 and the pupil center of their second eye 1-2 to the center of symmetry of their head are not equal. These differences may be 1 mm – 2 mm, which is sufficient to cause significant errors if the measurements are analyzed assuming symmetrical positioning of eyes 1-1 and 1-2. Therefore, in embodiments of the system 310 used to determine binocular alignment, it is advantageous not only to make the overall pupillary distance (“PD”) adjustable to accommodate patient-to-patient differences, but also to make the first / left eye single pupillary distance 4-1 defined relative to center 311 adjustable independently of the second / right eye single pupillary distance 4-2 defined similarly relative to center 311. In this embodiment, this is achieved by making the first eye optic unit 315-1 adjustable relative to the nose bridge 370 in the horizontal lateral / x direction to accommodate the single pupillary distance 4-1 of the first eye 1-1, as indicated by the thick arrow; and by making the second optic unit 315-2 adjustable relative to the nose bridge 370 in the horizontal lateral / x direction to accommodate the single pupillary distance 4-2 of the second eye 1-2. In some cases, the same objective can be achieved by making only the first eye tracker assembly 340-1 and the second eye tracker assembly 340-2 adjustable relative to the nose bridge 370 in the horizontal lateral direction.

[0171] Figure 22Further features of embodiments of a system 310 for determining binocular alignment are illustrated. Some embodiments may include a graphical user interface 380 configured for a medical operator to interact with a computer 350 to manage the determination of binocular alignment. This graphical user interface 380 may display to the medical operator (such as an optometrist or technician) infrared images captured by a first IR camera 348-1 and a second IR camera 348-2, the movement of eyes 1-1 and 1-2, available diagnostic steps for selection therefrom, and parameters for setting the diagnostic process, etc.

[0172] Further embodiments of the system 310 for determining binocular alignment may include a patient communication interface 385, such as a speaker, for guiding a patient through the steps required to determine binocular alignment. These instructions may come from a remote operator, or they may be pre-recorded and synchronized with the projection of specific visible images 326-1 and 326-2 by the computer 350. Other embodiments of the patient communication interface 385 may include a patient feedback portal for receiving feedback from the patient. Examples include buttons, trackwheels, touchpads, microphones, and audio interaction devices. Using any of these patient feedback portals, the patient can select feedback in response to steps of the diagnostic process. In an example, the computer 350 may begin adjusting the portrait / z-direction of the first display 322-1, and the speaker of the patient communication interface 385 may convey a pre-recorded instruction to the patient: “Press the button to indicate when the image is clear.” When the patient presses the button on the patient communication interface 385, the computer 350 may record the portrait / z-position of the first display 322-1, which provides information about the patient's prescription or the optical power of the eye 1-1. Alternatively, the computer can move the projected visible images 326-1 and 326-2 in the horizontal / x-direction on the first display 322-1 and the second display 322-2, and require the patient to indicate via a button when the two images 326-1 and 326-2 merge or when the fusion of the two images is broken. The horizontal / x-direction of the two images 326-1 and 326-2 provides information about the binocular alignment of the patient's eyes 1-1 and 1-2.

[0173] Figure 23The illustration shows that in some embodiments, the first eye tracker assembly 340-1 may include a first autorefractor 400-1 to determine refractive information about the first eye 1-1; and the second eye tracker assembly 340-2 may include a second autorefractor 400-2 to determine refractive information about the second eye 1-2. As previously mentioned, the second autorefractor 400-2 may be similar to the first autorefractor 400-1 and therefore does not need to be explicitly shown. The refractive information may simply be the refractive power of the eye under study required to perform method 100. For example, the patient's prescription may have changed without her / his knowledge since the last optometrist's examination. Or the optometrist may want to track the degree of accommodation in response to movement of the first display 322-1 in the longitudinal / z-direction. Or the optometrist may want to examine higher-order astigmatism or aberrations.

[0174] In an embodiment, the first autorefractor 400-1 may include a first wavefront (WF) infrared (IR) light source 402-1 to project WF IR light 402b-1 into a first eye. The first WF IR light source 402-1 may have many different embodiments, including LEDs, LED arrays, superradiative LEDs called SLEDs, and extended-beam lasers, etc. The WF IR light 402b-1 may be guided through a first collimator 404-1 and a first polarization beam splitter 406-1, the transmission polarization plane of the first polarization beam splitter 406-1 being aligned with the polarization plane of the first WF IR light source 402-1. The WF IR light 402b-1 may be coupled into the optical path of the first eye tracker assembly 340-1 via a first beam splitter 410-1 (optionally via an optional first refractive lens 408-1). Figure 23As shown, from here, WF IR light 402b-1 can be guided to the first eye 1-1 via the main optical path of the first eye tracker assembly 340-1, which includes the first visible transparent IR mirror 324-1 and the first lens assembly 360-1. The WF IR light 402b-1 (typically pencil-beam-like) is then reflected from the retina of the first eye 1-1 into a wider spatial angle as reflected WF IR light 402r-1. As the reflected WF IR light 402r-1 propagates through the lens and cornea of ​​the first eye 1-1, its extended wavefront is modified by refraction through the lens and cornea, thus acquiring information about the refractive properties of the lens and cornea of ​​the first eye 1-1. The reflected WF IR light 402r-1 propagates backward through the main optical path of the first eye tracker assembly 340-1, is separated by the first beam splitter 410-1, and is finally guided by the first polarization beam splitter 406-1 to the first microlens array 412-1. The first microlens array 412-1 is configured to receive the reflected WF IR light 402r-1 from the first eye 1-1 and split it into beamlets. These beamlets are then captured by the first wavefront camera 414-1 and analyzed to determine the refractive information they carry about the first eye 1-1.

[0175] The above-described embodiment of the automated refractometer 400-1 largely follows the design of the Shack-Hartmann wavefront analyzer. Other embodiments may use other wavefront analysis designs, such as Talbot-Moire interferometry, slit-lamp technology, Tscherning aberration measurement, focimeter technology, etc. In fact, focimeter devices can capture the optical properties of the eye beyond spherical / refractive power. These properties include cylindrical power and axis information, among others.

[0176] The system 310, equipped with an automated refractometer 400-1, for determining binocular alignment provides another useful diagnostic method. One type of binocular alignment problem is called "accommodative lag." This refers to the phenomenon where, when an object is presented to the patient at a presentation distance d1, the patient's eyes focus at a different distance d2, which is not equal to d1. Typically, d2 is greater than d1: d2 > d1. The system 310 with the automated refractometer 400-1 can identify and diagnose this accommodative lag.

[0177] At a higher conceptual level, the primary objective of the system 310 used to determine binocular alignment is to diagnose and characterize the cooperation and cross-linking of the two systems that control human vision: the focusing system, which uses the ciliary muscle to focus the lens on an object at actual distance; and the convergence system, which uses the six extraocular muscles to rotate the eyes to see an object at actual distance. Figures 17-23Embodiments of the system 310 for determining binocular alignment provide high-quality diagnostic information about these cross-linking systems through several design choices, including: they simulate objects using a first display 322-1 and a second display 322-2 actuated in the longitudinal / z-direction; they use a first optical unit 315-1 and a second optical unit 315-2 actuated in the horizontal direction; and optionally they include a first autorefractor 400-1 and a second autorefractor 400-2. These design choices enable the system 310 for determining binocular alignment to diagnose and characterize the cooperation and cross-linking of the focusing and convergence systems in an integrated “closed-loop” manner. Therefore, embodiments of the system 310 for determining binocular alignment are configured to determine the convergence and accommodation responses in an integrated manner by configuring the first display 322-1, the first eye tracker assembly 340-1, the second display 322-2, and the second eye tracker assembly 340-2 to determine the convergence response and the first autorefractor 400-1 and the second autorefractor 400-2 to determine the accommodation response.

[0178] For the sake of completeness, let's reiterate what was mentioned earlier. Figures 11-16 The described method 100 for determining binocular alignment. A computer 350 may be configured to perform the steps of method 100. Thus, in some embodiments, the computer 350 may be configured to determine the patient's gaze difference as the amount of angular misalignment between the central target and the peripheral fusion lock around the image-moving target with a blank center, as part of the determination of binocular alignment.

[0179] In some embodiments, the computer 350 may also be configured to determine the total gross phoria as the average amount of angular misalignment between the first eye 1-1 and the second eye 1-2 when the first display 322-1 and the second display 322-2 display different images (only one eye is focused on the target at a time), as part of determining binocular alignment.

[0180] Figures 24-25The illustration shows an embodiment of a system 310 for determining binocular alignment. The system includes: a first optical unit 315-1, comprising a first display 322-1 and a first eye tracker assembly 340-1. The first display 322-1 displays an image for a first eye 1-1 and is actuated in a lateral actuation direction according to a simulated distance and the optical power of the first eye 1-1. The first eye tracker assembly 340-1 tracks the gaze direction of the first eye 1-1 and is adjustable in the horizontal direction to accommodate the interpupillary distance of the first eye 1-1; and a second optical unit 315-2, comprising a second display... The system includes a display 322-2 and a second eye tracker assembly 340-2. The second display 322-2 is used to display images for the second eye 1-2 and is actuated in a lateral actuation direction according to an analog distance and the optical power of the second eye 1-2. The second eye tracker assembly 340-2 is used to track the gaze direction of the second eye 1-2 and is adjustable in the horizontal direction to accommodate the interpupillary distance of the second eye 1-2. A computer 350, coupled to the first optical unit 315-1 and the second optical unit 315-2, is used to determine binocular alignment based on the gaze directions of the first eye 1-1 and the second eye 1-2. Figures 17-23 The significant difference in the embodiment is that the positioning of the first display 322-1 and the second display 322-2 is changed from a longitudinal arrangement to... Figures 24-25 The lateral arrangement in the embodiment. This difference alters the shape factor and dimensions of the entire system 310, which can be advantageous in a crowded optometrist's office. The lateral actuation direction can be either the horizontal lateral ("x") direction or the vertical lateral ("y") direction. Figure 24 In the middle, the lateral actuation direction is horizontal. Figure 25 In the middle, it is vertical.

[0181] Figure 25The latter vertical embodiment is illustrated in more detail, focusing on the first eye 1-1. The elements of the system 310 for determining binocular alignment, associated with the second eye 1-2, are similar and are not shown for clarity. In the system 310 for determining eye alignment, the first eye tracker assembly 340-1 may include one or more first infrared light-emitting diodes 342-1 to project an infrared eye-tracking beam 342b-1 onto the first eye 1-1; a first infrared light source 344-1—which may include several individual LEDs—to illuminate the first eye 1-1 with infrared imaging light 344b-1; a first infrared camera 348-1 positioned along the longitudinal direction to detect the infrared eye-tracking beam and the infrared imaging light, both of which are reflected from the first eye and are collectively labeled 345b-1; and a first infrared transmission visible mirror 324'-1 for transmitting the reflected infrared eye-tracking beam and infrared imaging light 345b-1 from the first eye 1-1 to the first infrared camera 348-1 along the longitudinal direction; and redirecting the image from the lateral actuation direction of the first display 322-1 to the longitudinal direction toward the first eye 1-1. The second eye tracker assembly 340-2 may include (not shown for clarity) one or more second infrared light-emitting diodes 342-2 for projecting an infrared eye-tracking beam 342b-2 onto the second eye 1-2; a second infrared light source 344-2 for illuminating the second eye 1-2 with infrared imaging light 344b-2; a second infrared camera 348-2 positioned along the longitudinal direction to detect the infrared eye-tracking beam and the infrared imaging light, both reflected from the second eye and collectively labeled 345b-2; and a second infrared transmission visible mirror 324'-2 for transmitting the reflected infrared eye-tracking beam and infrared imaging light 345b-1 from the second eye 1-2 to the second infrared camera 348-2 along the longitudinal direction; and redirecting the image from the lateral actuation direction of the second display 322-2 to the longitudinal direction toward the second eye 1-2. Typically, the beams arriving at and departing from the eyes 1-1 and 1-2 propagate through the first lens assembly 360-1 and the second lens assembly 360-2. Figures 17-23 Many variations and modifications of the embodiments are in Figures 24-25 Similar implementations can be found in other embodiments. For example, horizontal adjustability can be implemented only for the first eye tracker assembly 340-1 and the second eye tracker assembly 340-2, or for these assemblies together with the first display 322-1 and the second display 322-2 (with or without the first lens assembly 360-1 and the second lens assembly 360-2), as is the case for... Figures 17-23 As described in the embodiments.

[0182] A head-mounted device-based system for determining eye alignment

[0183] Figures 26-31 illustrate the combination of Figure 1- Figure 25 Another embodiment of the above-described system and method, which is technically extended, is based on a head-mounted device. Figures 26A-26B The illustration depicts a head-mounted device 500 that can be used in this context. Similar technical names for these devices include virtual reality goggles, personal projection equipment, etc. The head-mounted device 500 may include a stereoscopic display 522, focusing optics 530, and an eye tracker 540. Figures 26A-26B In the images, the head-mounted device is shown with its skin, so some of the components are not clearly visible. These figures are provided more as a realistic representation of some embodiments. Figure 27 The same key components are clearly shown in schematic diagrams or conceptual illustrations. Head-mounted device 500 may include a left stereoscopic display 522L and a right stereoscopic display 522R. In some embodiments, these two displays are actually the left and right sides of the same single stereoscopic display, visually separated only by a central divider. The head-mounted device may also include a left focusing optics 530L and a right focusing optics 530R. These may be single lenses or lens assemblies. They may include fixed optics or adjustable optics. In most head-mounted devices today, focusing optics are designed to have a fixed focal length to allow the observer to adjust to an object 1.25 meters away. Furthermore, eye tracker 540 may include left-eye tracking illumination 544L and right-eye tracking illumination 544R, as well as left-eye tracking cameras 548L and right-eye tracking cameras 548R.

[0184] These components are similar to those with similar labels in the previous embodiments, such as... Figures 6A-6B , Figures 8A-8B , Figure 9 , Figures 17-25 As described above. For example, stereoscopic display 522 is similar to 322 of the previous stereoscopic display screen 22 and stereoscopic display 20. Focusing optics 530 is similar to adjustable optics 30, which may include an integrated optometry wheel 32, an adjustable optical lens 34, and a lens assembly 360. Finally, eye tracker 540 is similar to eye trackers 40 and 340, wherein eye-tracking illumination 544 may be similar to IR light source 44 and IR LED 42, and IR light source 344 and IR LED 342; and eye-tracking camera 548 is similar to IR cameras 48 and 348. Binocular markings have been changed from -1 and -2 to L and R to indicate the left and right eyes. Any embodiment of these previously described similar elements can be used in the embodiments of head-mounted device 500 described herein.

[0185] Figure 28 A method 600 for determining eye alignment is shown, the method comprising:

[0186] (a) The following steps were used to measure unrelated latent strabismus at the first simulated distance in 620 patients.

[0187] - Using the stereoscopic display 522 of the head-mounted device 500, a fusionable image 622 of a target for a first eye and a second eye with a first parallax 206 corresponding to a first simulated distance is presented at a screen distance;

[0188] - Using the stereoscopic display 522 of the head-mounted device 500, 624 non-fusionable images are presented at a screen distance by presenting a target with a first parallax 206 for the first eye and a non-associated targetless image 201 for the second eye, and

[0189] - Using the eye tracker 540 of the head-mounted device 500, measure 626 at least one of the first and second eyes for non-associated latent strabismus 208 in response to the presentation of a non-fusionable image.

[0190] These steps are followed by

[0191] (b) Determine the convergence and divergence of 640 patients at the first simulated distance using the following steps.

[0192] - Using a stereoscopic display 522 of a head-mounted device 500, a fusionable image 642 is presented to the first and second eyes at a screen distance, having a first parallax corrected by a measured non-associated heterophoria 208.

[0193] - Measured 644 presentation-associated latent strabismus in response to fusionable images using an eye tracker 540; and

[0194] - The convergence and divergence were determined to be a combination of 646 disparity, 206 non-associated heterophoria, 208 associative heterophoria, and 208 associative heterophoria.

[0195] As before, these method steps are embodiments of the previous methods adapted for head-mounted devices. Specifically, measurement 620 is similar to measurement 120, and determination 640 is similar to determination 140, as per [reference to...]. Figure 11 , Figure 12 and Figure 14 As described. Parallax is similar to viewing distance convergence 206. Convergence is related to accommodative convergence, but is modified because the fixed distance (or accommodative distance) in the head-mounted device 500 is fixed and not affected by the analog distance. This difference is sufficient to be expressed in the modified terminology. Finally, the non-associated targetless image 201 is similar to the distributed image 201. The first eye and the second eye can be the left eye and the right eye, or vice versa. In addition, the screen distance can be interchangeably referred to as the display distance.

[0196] The method 600 described above outlines the steps and sub-steps for determining convergence and divergence at a specific simulated distance. An important aspect of method 600 also includes determining the convergence and divergence of distant and near objects to determine whether the patient requires prescription glasses that have different effects or modifications on the convergence and divergence of the patient's near and distance vision.

[0197] Therefore, in some embodiments, method 600 includes the following steps.

[0198] - Repeat step (a) 620 by measuring the patient's unrelated latent strabismus 208 at a second simulated distance using the stereoscopic display 522 of the head-mounted device 500 at the screen distance;

[0199] - Repeat step (b) 640 by determining the patient's convergence at a second simulated distance using the stereoscopic display 522 of the head-mounted device 500 at the screen distance;

[0200] - The gradient convergence-divergence ratio is calculated as the ratio of the difference between the convergence and divergence at the first and second simulated distances to the difference between the reciprocal of the first and second simulated distances; and

[0201] - Prescribe eyeglasses with contour prisms to patients based on gradient convergence-divergence ratio.

[0202] The first distance here can be the typical distance for far vision used in optometry, such as 6 meters (or a comparable alternative), and the second distance can be the typical distance for near vision, such as 0.4 meters or 0.5 meters.

[0203] The above steps can be summarized as the so-called "regulatory convergence and regulation" adaptation or AC / A ratio:

[0204]

[0205] Where GV = (geometric) convergence, set as half the interpupillary distance in centimeters, divided by the simulated distance in meters; A = accommodative response = 1 / simulated distance (in meters); and Ph = heterophoria, with a corresponding definition. Subscripts 1 and 2 refer to these quantities measured for distance and near vision targets. The AC / A ratio formula is adapted for some of the previous embodiments in this document in the preceding equation (1). Similarly, for the current head-mounted device-based embodiments, the gradient convergence ratio GVR can be defined as

[0206]

[0207] Where P i For the first or second parallax, DPh i For the first or second unrelated heterophoria measured in step 620, and APhi For the first or second associated heterophoria measured in step 640, i can be 1 or 2. Using the notation described above and previously, disparity P acts as geometric convergence GV and also corresponds to distance convergence. Non-associated latent strabismus DPh corresponds to the previous And (stable) correlated latent strabismus APh corresponds to , such as regarding Figures 13A-13D to Figures 15A-15C The sum of these two heterophoria, DPh and APh, corresponds to the (total) heterophoria above: DPh + APh = Ph. The disparity P, or distance convergence, is the difference between the two heterophoria values. It is defined by geometry: it is the angle whose tangent is equal to half the interpupillary distance divided by the simulated distance, just like the geometric convergence / divergence (GV) above. All the aforementioned convergence and eccentricity angles can be defined directly as angles, or they can be defined via their tangents. The latter is more typical, in which case the convergence is given as... Where heterophoria is divided by 2, each heterophoric angle represents the average heterophoric angle for each eye as before. Since interpupillary distance is typically measured in centimeters while analog distances are measured in meters, a factor of 100 is introduced before. Alternative formulas that express the same concept for a two-eye combination, or use angles instead of tangents, or measure all distances in the same units (all meters or all centimeters) are obvious analogues to this expression. Finally, there is a different notation convention for heterophoria. We use a notation derived from parallax. The convention of subtracting positive latent strabismus from 206 is used. However, the concepts described in this paper can be implemented equally efficiently using either the + or - sign convention.

[0208] As discussed above, the first disparity P1 corresponding to the first simulated distance is an angle whose tangent is equal to half of the patient's interpupillary distance divided by the first simulated distance; and the second disparity P2 corresponding to the second simulated distance is an angle whose tangent is equal to half of the patient's interpupillary distance divided by the second simulated distance.

[0209] Figures 29A-29B As shown in some embodiments of method 600, presenting images for a first eye and a second eye with a first parallax corresponding to a first simulated distance (see steps 622 and 642) includes: presenting a first image and a second image whose image centers are shifted from the interpupillary distances of the patients to each other by a refraction-corrected distance offset equal to half the interpupillary distance of the patients multiplied by the ratio of the screen distance to the first simulated distance and corrected for refraction according to the focusing optics of the head-mounted device; wherein the images are either fusionable or non-fusionable images. Figure 29AA simplified conceptual scenario is illustrated. To describe the geometry and optics in detail, a reference system is employed by referring to the points where the patient's gaze directly ahead intersects with the stereoscopic display 522 as left and right reference points 523L or 523R. The image centers 523ICL and 523ICR are positioned at these reference points 523L and 523R, thus presenting the image to the patient as if the image / object / target were at infinity. Accordingly, presenting the image centers 523ICL and 523ICR shifted inward from these centers 523L / R by distance offsets 524L and 524R (equal to half the patient's interpupillary distance multiplied by the ratio of the screen distance to the first simulated distance) is an effective way to simulate the object appearing at the first simulated distance for the patient.

[0210] Figure 29B This illustrates an additional technical aspect of most head-mounted devices 500, including focusing optics 530, which are also important for presenting images to the patient at a simulated distance. Of course, these focusing optics 530 have refractive properties and influence... Figure 29A The refractive power is determined by a simple geometric relationship. This requires recalibrating or correcting the distance offset 524L / R. However, this is convenient, as the reference point 523L / R of the stereoscopic display 522L / R can be naturally defined to be aligned with the center of the focusing optics 530L / R. In detail, the recalibration or correction of the distance offset 524L / R based on the refraction of the focusing optics 530 includes: using the laws of geometric optics to calculate a refraction-corrected distance offset 525L / R for the system, which is separated by eye-optics distance 526 and optics-screen distance 527, respectively, for the eye, the focusing optics 530 with focusing power, and the stereoscopic display 522L / R, so that the patient can perceive the image at the first simulated distance. Figure 29B For the left eye, it is shown that this refractive correction results in the image center 523ICL of the presented image being shifted from the reference point 523L by not only a distance offset 524L, but also a refractively corrected distance offset 525L. For the right eye, the same concept is illustrated by showing an unresolved geometric parallax 206. Instead, it is based on the parallax corrected by refraction, 206RC. It is used to present images and reflect this.

[0211] Figure 30Some head-mounted devices 500 are shown to have additional features, such as (lateral) adjustable distances for the left and right focusing optics 530L and 530R. This allows the head-mounted device 500 to be adjusted to optimally match the patient's respective interpupillary distance, thereby minimizing unintended refractive deviations caused by misalignment of the eye, focusing optics 530, and image center 523IC. In such a head-mounted device 500, method 600 may include: determining the patient's interpupillary distance; aligning a reference point 523L / R of the stereoscopic display 522L / R with the patient's pupil, separated by the determined interpupillary distance; calculating a refractively corrected distance offset 525L / R using the determined interpupillary distance; and shifting the calculated refractively corrected distance offset 525L / R from the set reference point 523L / R.

[0212] As previously mentioned, in these head-mounted devices 500, the focusing optics 530L / R of the head-mounted device 500 can be adjusted laterally according to the determined interpupillary distance. Figure 30 An adjustable head-mounted device 500 in operation is shown, wherein after treating patient 1, the spacing of the left and right focusing optics 530L / R is adjusted for patient 2, and the two patients have different interpupillary distances PD1 and PD2. The focusing optics 530L and 530R are shown as greatly reduced in size, simply to increase the clarity of the diagram.

[0213] Figure 31A An embodiment of step 622 is shown, presenting a fusionable image including targets for a first eye and a second eye with a first parallax. Here, the targets can be a left target 623TL and a right target 623TR, for example, a clearly depicted cross or small circle or dot. The fusionable image may also include non-target elements, such as a group of spheres, star-shaped objects, or any other objects. These non-target elements can be static or dynamic and are located at the center or periphery.

[0214] Figure 31B An embodiment of step 624 is shown, in which an unblended image is presented by presenting the target 623TL to the left eye and an unrelated target-free image 623DTR to the right eye. As before, the unrelated target-free image 623DTR can be central or peripheral, and can be static or dynamic. In some cases, as shown, using a repeating set of dots with different brightness can yield good results. Many other unrelated target-free images 623DTR can also be presented on the right stereoscopic display 522R, as long as they cannot be blended with the image of the left target 623TL.

[0215] As discussed above, the fact that the screen distance (or display distance) in some head-mounted devices 500 is fixed and cannot be adjusted for different simulated distances may limit the integrity of the simulated experience performed on the patient. Therefore, some embodiments of method 600 may include presenting the image using additional distance simulation techniques, such as using a blur factor or chromatic aberration blur factor corresponding to a first simulated distance; wherein the image may be a blendable image in steps 622 and 642, or a non-blending image in step 624. Introducing these blur factors or chromatic aberration blur factors can improve the realism of the simulation of the image at the first or second simulated distance.

[0216] Several aspects described below are similar to or even identical to the methods and steps described previously. Specifically, similar to... Figure 12 and Figures 13A-13D In an embodiment of method 600, step 626, which measures non-associated latent strabismus in response to the presentation of an unfusionable image in at least one of the first and second eyes, may include the following steps.

[0217] - As in step 126, an eye tracker is used to track at least one of the first and second eyes in response to the rotation of the projection;

[0218] - As in step 128, identify the relaxation state from the stability of the tracked rotations; and

[0219] - As in step 130, non-associated latent strabismus is measured by measuring the orientation of at least one of the first and second eyes in a relaxed state using an eye tracker 540L / R.

[0220] In some embodiments, similar to Figure 14 and Figure 15A And step 142, step 642, which presents the fused image, may include: using the stereoscopic display 522 of the head-mounted device 500, presenting a first image for a first / left eye and a second image for a second / right eye with a first disparity 206 corrected for by a measured non-associated heterophoria 208. As previously described, the first and second images may be peripheral, dynamic, or static, etc.

[0221] In addition, similar to Figure 14 and Figure 15B In addition to step 144, in some embodiments, determining step 640 may include using the stereoscopic display 522 of the head-mounted device 500 to alternately present a first added center image 212L or 212-1 to a first eye; and to present a second added center image 212R or 212-R to a second eye.

[0222] In some embodiments, the next step may be with Figure 14Step 146 is similar to the following steps: using eye tracker 540, the adjustment of the first / left eye in response to the projection of the first added central image 212L is tracked, and the adjustment of the second / right eye in response to the projection of the second added central image 212R is tracked.

[0223] Determining step 640 may also include... Figure 14 and Figure 15C Step 148 is similar to the following steps: using a stereoscopic display 522 to alternately present the latent strabismus with the first iterative correlation. or The first added center image 212L is shifted to reduce the adjustment of the first / left eye; and a latent strabismus with a second iterative correlation is presented. or The second added center image 212R is shifted to reduce the adjustment of the second / right eye.

[0224] Determining step 640 may also include... Figure 14 and Figure 15C Step 150 is similar to the following steps: using an eye tracker 530, the first eye is tracked to adjust the presentation of the first eye in response to the shifted first added center image 212L; and the second eye is tracked to adjust the presentation of the second eye in response to the shifted second added center image 212R.

[0225] Furthermore, determining 640 may include similar to Figure 14 and Figure 15C Step 152 in the process involves determining whether the effective adjustment of the first and second eyes is less than an adjustment threshold. The next step could be a bifurcation step similar to step 148: if the effective adjustment of the first and second eyes is greater than the adjustment threshold, then the first added center image 212 with the shifted presentation is restored; and if the effective adjustment of the first / left eye and the second / right eye is less than the adjustment threshold, then the associative latent strabismus is determined from the last first iteration. or and the last second iteration of related latent strabismus or Identify stable associative latent strabismus.

[0226] These steps can lead to something similar to Figure 14 Step 156 of the integration process: Integrate the disparity P 206 or the distance convergence / divergence. The combination of the measured non-associated latent strabismus DPh and the determined stable associated latent strabismus APh is identified as the convergence / divergence degree corresponding to the first simulated distance. In the formula, this combination is simply the sum of these three quantities: or .

[0227] The steps described above, similar to steps 126-128-130, expand upon and provide details for measurement step 620; while the steps similar to steps 142-144-146-148-150-152-154-156 expand upon and provide details for determination step 640 of method 600.

[0228] In some embodiments of method 600, when the first simulated distance corresponds to near vision (such as 0.4 meters or 0.5 meters), both the measurement step 620 and the determination step 640 of method 600 are performed at a downward viewing angle. Such embodiments determine near vision convergence and divergence at a viewing angle below the equator, thus more realistically simulating the final use of prescription glasses, since the near vision zone of a progressive lens is typically below the equator of the lens.

[0229] Finally, an important and advantageous aspect of method 600 is that it can be performed without soliciting a patient's (subjective) response. Therefore, since method 600 is performed solely based on objectively measured quantities and parameters, it is expected to eliminate subjective feedback from the patient that could lead to significant non-reproducibility, bias, or uncertainty in the measurement results.

[0230] The method 600 described above can be used in a system for determining binocular alignment, the system including a head-mounted device 500 having a stereoscopic display 522 and an eye tracker 530, configured to:

[0231] (a) The unassociated heterophoria of 620 patients at a first simulated distance was measured by: presenting a fusionable image of a target for a first eye and a second eye with a first disparity corresponding to the first simulated distance at a screen distance using a stereoscopic display of a head-mounted device; presenting a non-fusionable image by presenting a target for the first eye with a first disparity and an unassociated targetless image for the second eye at a screen distance using a stereoscopic display of a head-mounted device; and measuring the unassociated heterophoria of at least one of the first and second eyes in response to the presentation of the non-fusionable image using an eye tracker of the head-mounted device; and

[0232] (b) The convergence and divergence of 640 patients at a first simulated distance were determined by presenting a fusionable image with a first disparity having been corrected for unrelated heterophoria to the first and second eyes at a screen distance using a stereoscopic display of a head-mounted device; measuring the related heterophoria in response to the presentation of the fusionable image using an eye tracker; and determining the convergence and divergence as a combination of disparity, unrelated heterophoria, and related heterophoria.

[0233] While this document contains numerous details, these details should not be construed as limiting the scope of the invention or the scope of claims, but rather as descriptions of features specific to particular embodiments of the invention. Certain features described herein in the context of individual embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented separately in multiple embodiments or in any suitable sub-combination. Furthermore, while features may be described above as functioning in certain combinations and even initially claimed so, in some cases, one or more features from the claimed combination may be removed from the combination, and the claimed combination may involve sub-combinations or variations thereof.

Claims

1. A method for determining eye alignment, the method comprising: (a) Measure the patient’s unrelated latent strabismus at the first simulated distance using the following method: A stereoscopic display using a head-mounted device presents a fusionable image of a target for a first eye and a second eye, including a first parallax corresponding to a first simulated distance, at a screen distance. By using a stereoscopic display of a head-mounted device to present a target with a first parallax for the first eye and an unrelated targetless image for the second eye at a screen distance, an unfusionable image is presented. Eye trackers from a head-mounted device are used to measure at least one of the first and second eyes for non-associated latent strabismus in response to the presentation of a non-fusionable image; as well as (b) Determine the patient's convergence or divergence at the first simulated distance using the following: A stereoscopic display using a head-mounted device presents a fusionable image at a screen distance to the first and second eyes, with a first disparity having a measured non-associated heterophoria correction. Associative latent strabismus in response to the presentation of fusionable images was measured using an eye tracker; and Convergence and divergence were defined as a combination of parallax, non-associated heterophoria, and associative heterophoria.

2. The method of claim 1, comprising: Step (a) was repeated by measuring the patient’s unrelated latent strabismus at a second simulated distance using a stereoscopic display of a head-mounted device at the screen distance. Step (b) was repeated by determining the patient’s convergence at a second simulated distance using a stereoscopic display of a head-mounted device at the screen distance. The gradient convergence-divergence ratio is calculated as the ratio of the difference between the convergence and divergence at the first simulated distance and the second simulated distance to the reciprocal of the first simulated distance and the reciprocal of the second simulated distance; and Based on the gradient convergence-divergence ratio, eyeglasses with contour prisms are prescribed to patients.

3. The method of claim 2, wherein: The first disparity corresponding to the first simulated distance is the angle whose tangent is equal to half the patient's interpupillary distance divided by the first simulated distance; and The second parallax corresponding to the second simulated distance is the angle whose tangent is equal to half the patient's interpupillary distance divided by the second simulated distance.

4. The method of claim 1, wherein presenting an image having a first parallax corresponding to a first simulated distance to the first eye and the second eye comprises: A first image and a second image are presented, their image centers shifted from the interpupillary distances of the patients to each other by a refraction-corrected distance offset equal to half the patient's interpupillary distance multiplied by the ratio of the screen distance to the first simulated distance, and corrected according to the refraction of the focusing optics of the head-mounted device; wherein The image can be either a mergeable image or a non-mergeable image.

5. The method of claim 4, wherein the correction based on refraction comprises: Using the laws of geometric optics, the system calculates a refraction-corrected distance offset for the eye, which is separated from the eye-optical distance and the optical-screen distance, the focusing optics with focusing power, and the stereoscopic display, so that the patient perceives the image at the first simulated distance.

6. The method of claim 4, comprising: Determine the patient's pupillary distance; The reference point of the stereoscopic display is aligned with the patient's pupil, separated by the determined interpupillary distance; Calculate the refraction-corrected distance offset using the determined interpupillary distance; as well as The distance offset calculated by shifting the image center from the set reference point.

7. The method of claim 6, comprising: The focusing optics of the head-mounted device are adjusted laterally according to the determined interpupillary distance.

8. The method of claim 1, comprising: Present an image with a blur factor or chromatic blur factor corresponding to the first simulated distance; in The image can be either a mergeable image or a non-mergeable image.

9. The method of claim 1, wherein measuring at least one of the first eye and the second eye for non-associated latent strabismus in response to the presentation of a non-fusionable image comprises: In response to projection, an eye tracker is used to track the rotation of at least one of the first and second eyes; Identify relaxation states from the stability of the tracked rotations; as well as Unassociated latent strabismus is measured by using an eye tracker to measure the orientation of at least one of the first and second eyes in a relaxed state.

10. The method of claim 1, wherein presenting the fusionable image is used to determine including: Using a stereoscopic display of a head-mounted device, a first image is presented to a first eye and a second image is presented to a second eye using a first disparity corrected for measured non-associated heterophoria.

11. The method of claim 10, wherein: The first and second images are peripheral, dynamic, or static.

12. The method of claim 10, wherein the determination comprises: Stereoscopic displays using head-mounted devices are used in an alternating manner: The first added center image is presented to the first eye; as well as The second added center image is presented to the second eye.

13. The method of claim 12, wherein the determination comprises: Using stereoscopic displays in an alternating manner: Presenting a first added central image with first iterative correlational heterophoria shift to reduce the adjustment of the first eye; as well as A second, additional central image is presented with a second iteration of correlated heterophoria shift to reduce the adjustment of the second eye.

14. The method of claim 13, wherein the determination comprises: Using an eye tracker: The first eye adjusts in response to the shift in the presentation of the first added center image; as well as The second eye adjusts in response to the shift in the presentation of the second added center image.

15. The method of claim 14, wherein the determination comprises: Determine whether the effective adjustment of the first and second eyes is less than the adjustment threshold.

16. The method of claim 15, wherein the determination comprises: When the effective adjustment of the first and second eyes exceeds the adjustment threshold, the shifted first added center image is restored; as well as When the effective adjustment of the first and second eyes is less than the adjustment threshold, stable associative heterophoria is identified from the last first-iteration associative heterophoria and the last second-iteration associative heterophoria.

17. The method of claim 16, wherein the determination comprises: The combination of parallax, non-associated heterophoria, and stable associative heterophoria is identified as the convergence / divergence corresponding to the first simulated distance.

18. The method of claim 1, wherein: When the first simulated distance corresponds to near vision, the measurement and determination steps of the method are performed at a downward viewing angle.

19. The method of claim 1, wherein: The method is performed without soliciting a response from the patient.

20. A system for determining eye alignment, comprising: A head-mounted device having a stereoscopic display and an eye tracker, the head-mounted device being configured to: (a) Measure the patient’s unrelated latent strabismus at the first simulated distance using the following method: A stereoscopic display using a head-mounted device presents a fusionable image of a target for a first eye and a second eye, including a first parallax corresponding to a first simulated distance, at a screen distance. By using a stereoscopic display of a head-mounted device to present a target with a first parallax for the first eye and an unrelated targetless image for the second eye at a screen distance, an unfusionable image is presented. The non-associated latent strabismus of at least one of the first and second eyes in response to the presentation of a non-fusionable image is measured using an eye tracker on a head-mounted device. as well as (b) Determine the patient's convergence or divergence at the first simulated distance using the following: A stereoscopic display using a head-mounted device presents a fusionable image at a screen distance to the first and second eyes, with a first disparity having a measured non-associated heterophoria correction. Associative latent strabismus in response to the presentation of fusionable images was measured using an eye tracker; and Convergence and divergence were defined as a combination of parallax, non-associated heterophoria, and associative heterophoria.

Images