Method and apparatus for refraction and vision measurement

Abstract

Consumer products such as refractive measurement devices can be used to obtain refractive measurement results, allowing consumers to track their vision without visiting an optometrist or ophthalmologist. Such consumer products can work in conjunction with a smartphone or other product with a touch screen that presents an image to the refractive measurement device. Smartphones may have a resolution ratio, sometimes measured in PPI or pixels per inch that is unknown to the user and / or the refractive measurement device. One aspect of the present invention is to provide an optical interface for a user to manually match the viewing port boundaries of a smartphone to coincide with the viewing port boundaries of a refractive measurement device. Another aspect of the present invention is the use of pre-distortion in the image presented to the user. By noting the corrective actions applied by the user on the refractive measurement device, the user's own refractive error can be derived.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is a continuation or continuation-in-part of the following patent application, the contents of which are incorporated herein by reference.

[0003] U.S. patent application 16 / 685,017, filed on November 15, 2019, and entitled Automated Personal Vision Tracker, is a continuation-in-part of U.S. patent application 16 / 276,302, filed on February 14, 2019, and entitled Optical Method to Assess the Refractive Properties of an Optical System. U.S. patent application 16 / 276,302 is now U.S. Patent 10,488,507, which is a continuation-in-part of U.S. patent application 15491557 filed on April 19, 2017, rather than Patent 10,206,566, which claims priority to provisional patent application 62409276 filed on October 17, 2016.

[0004] This application is a partial continuation of U.S. patent application No. 16 / 176,631 filed on October 31, 2018, and the invention name is SmartPhone Based Virtual Visual Charts for Measuring Visual Acuity. The application claims the priority date of provisional patent application No. 62 / 579,558 as October 31, 2017.

[0005] This application claims priority to provisional patent application 62 / 876,889 filed on July 22, 2019.

[0006] No copyright and trademark notices apply

[0007] This application contains material that is or may be protected by copyright and / or trademark. The copyright and trademark owners have no objection to the facsimile reproduction of any patented invention as it appears in the Patent and Trademark Office files or records, but otherwise all copyright and trademark rights are reserved regardless. These trademarks may include "EyeQue," "PVT," "Personal VisionTracker," "Insight," "VisionCheck," and others. Technical Field

[0008] The present invention generally relates to vision testing and refraction measurement systems that are attached to a display, such as personal vision tracking systems, visual field calibration systems, and insight systems. More specifically, the present invention relates to apparatus and methods for measuring characteristics of a display and correcting optical aberrations in such systems. Any system intended to measure vision and ocular characteristics (e.g., refraction), where the system includes a display, where the optical system consists of refractive elements and / or reflective elements (e.g., lenses and / or mirrors) may encounter two major problems: the characteristics of the display may be unknown (e.g., the display may be part of a smartphone and the phone resolution is not well reported), and the optical system creates aberrations for the displayed image. The proposed invention describes methods and apparatus for overcoming these problems. Background Art

[0009] Vision is arguably the most important sense organ. The human eye and its direct connection to the human brain is a very advanced optical system. Light from the environment passes through the eye's optical system consisting of the cornea, pupil and lens and is focused to produce an image on the retina. As with all optical systems, the propagation of light through the eye's optics is affected by aberrations. The most common forms of aberrations in the eye are defocus and astigmatism. These low-order aberrations are responsible for the most common eye refractive conditions, myopia (ophthalmic myopia) and hyperopia (ophthalmic hyperopia). Higher-order aberrations also exist and can be most conveniently described by Zernike polynomials. These generally have less impact on visual function. The eye, like any other organ of the human body, can suffer from a variety of diseases and conditions, the most prominent of which are currently: cataracts, age-related macular degeneration (AMD), glaucoma, diabetic retinopathy and dry eye. Other conditions also exist and they should also be considered within the scope of this application.

[0010] Ophthalmic measurements are essential for eye health and proper vision. Those ophthalmic measurements can be divided into objective and subjective types. Objective types of measurements can provide physiological, physical (e.g., mechanical or optical), biological, or functional metrics without the need for input from the individual being measured (patient, subject, user, or consumer). Examples of objective tests include, but are not limited to, OCT (optical coherence tomography for three-dimensional and cross-sectional imaging of the eye), scanning laser ophthalmoscope (SLO, for spectral imaging of the retina), fundus images (for displaying retinal images), autorefractometers (for refractive measurements), keratometers (for providing corneal profiles), tonometers (for measuring IOP—intraocular pressure). Subjective measurements give metrics that are related to individual input. That is, they provide parameters that also take into account the individual's brain function, perception, and cognitive abilities. Examples of subjective tests include, but are not limited to, visual acuity tests, contrast sensitivity tests, comprehensive refractometer refraction tests, color vision tests, visual field tests, and personal vision tracking systems (EyeQuePVT) and Insight.

[0011] Currently, both objective and subjective eye examinations (measurements) are performed by an ophthalmologist or optometrist. The process typically involves the patient scheduling an appointment, waiting for the appointment, going to the appointment location (e.g., an office or clinic), waiting in line, using various tools for multiple tests, and potentially moving between different technicians and different ophthalmologists. The extended wait times for appointments and queuing at appointment locations, as well as the hassle of getting the tests done with different professionals and the duration of these tests seem to be daunting to many patients. Furthermore, the separate results associated with the process, and even the requirement to remember to start the process, can discourage patients from having the process.

[0012] Furthermore, approximately 2.5 billion people currently have no access to eye and vision care. In some parts of the world in particular, the cost of an eye exam can be considered prohibitive. This creates a barrier to eye care services in third world countries, for example. Cost, time consumption and perceived inconvenience also sometimes make repeated eye exams impossible to perform, especially at the required frequency. In special cases (e.g. after refractive or cataract surgery), repeated measurements may be necessary to track the progression of the patient's condition over time and the success of the surgery. Furthermore, even under normal circumstances, measurements taken in the doctor's office represent only one point in time. The circumstances in which the measurements are taken may not be optimal or fully represent the patient's characteristics. The patient may be tired, nervous or irritated (a doctor's visit can be very stressful, but the repeated tests and questions and choices made during the visit can also increase the patient's stress level), or simply be in a bad mood. Even the doctor's own psychological state may affect the way the measurements are taken. In addition to this, the time of day and other environmental conditions (whether direct, such as lighting conditions, or indirect, such as temperature) may affect the measurements and provide incomplete or erroneous information.

[0013] The availability of information on the Internet, especially including medical information, the increased awareness of preventive medicine, and the advent of telemedicine have allowed many people to take control of their health. In today's world, devices for screening, monitoring, and tracking medical conditions are very common, such as blood pressure measuring devices and blood glucose monitors. Technological advances allow people to be more independent in diagnosing, preventing, and tracking various health conditions. In addition, many people prefer to perform these activities in the comfort of their own homes without the need for appointments or other time-consuming activities. If something unusual occurs, they will call or email their physician to consult on the appropriate course of action.

[0014] Advances in technology have effectively made computers with screens and cameras ubiquitous in the form of laptops, tablets, and smartphones, thus leaving many people with devices that are already capable of processing, displaying, and recording information.

[0015] All of this creates a need for a range of devices that will enable users to perform ophthalmic measurements themselves at home in a timely and cost-effective manner. It should be clear that the quality of these measurements and their accuracy and precision should meet or exceed the standards of current measurement methods.

[0016] This vision can be further enhanced by using cloud-based data and analytics that have complete access to the entire history of patient examinations, tests, and measurements. In addition, the use of artificial intelligence (AI) will enable machine learning and big data-based diagnostics. This can be done by way of data mining, neural network decision making, and pattern detection and recognition as some examples of AI capabilities.

[0017] In summary, the vision of eye care in the near future will look like: A complete solution for eye and vision care for consumers and doctors; A set of remote, self-administered tests for disease and function; Measurements enabled by technology and devices, using AI for analysis, tracking, and reporting; Enhanced by big data statistics and insights.

[0018] In simple terms, for example: a person sits comfortably on the couch at home, uses a device to take various measurements, and then uploads the data to AI for analysis. AI will let the patient know the results and notify the doctor. AI will initiate alerts for this person and the doctor if necessary. Unless there is a serious problem (such as surgery), the person does not need to get up. All other issues will be handled remotely (such as email / phone / video conference with the doctor, ordering glasses, having them delivered to the home and direct delivery of doctor-prescribed drugs).

[0019] Despite the obvious move towards "targeting consumers", these methods could be easily implemented as models for more businesses. One example of such an implementation would have a hierarchical structure where entities such as hospitals, associations, or health insurance companies enable doctors to provide such devices and capabilities to their patients. These devices are all connected to the cloud through user accounts, and measurements are streamed directly into the user's account (and possibly their medical records). These accounts can be connected to one or more doctors, and can also be transferred and shared.

[0020] The known prior art failed to anticipate or disclose the principles of the present invention.

[0021] In the prior art, minimization of the field of view (FoV) and image size, especially in personal view tracking systems, provides a method to overcome distortion aberrations in the system, which causes the image presented to the user to form curved lines despite having straight lines on the display. The field of view calibration system contains an aspheric lens to overcome the distortion of the lines presented to the user. This type of hardware solution makes the system more complex and expensive.

[0022] The pixel density (PPI) property of a display is critical in determining the size of the image displayed. Scaling between different displays is required to allow the image to be displayed correctly. Current systems rely on input from the phone firmware to indicate the correct resolution in the form of PPI. Some current phones do not report this value correctly. Therefore for these phone displays, the correct PPI must be entered manually in the back end of the software.

[0023] Therefore, there is a long felt need in the art for the present invention. Summary of the invention

[0024] The present invention overcomes the deficiencies of the prior art by providing a non-obvious and unique combination and configuration of methods and components to calibrate optical aberrations in the system and allow a self-correcting method to measure display resolution.

[0025] The present invention overcomes the deficiencies of the prior art by using a calibration process to measure display resolution and create a correction map for distortion aberrations.

[0026] In an embodiment of the invention, the display is part of a smartphone. What is displayed to the user is a rectangle with the correct aspect ratio as the attached device. The attached device specifications are well known. The user then adjusts and aligns the rectangle on the screen to match the attachment profile of the device. The known specifications of the device and the input rectangle dimensions in pixels can then be used to calculate the phone resolution or more specifically its PPI. This can then be used for alignment and scaling of the image on the display. This, in turn, can be used to make visual acuity and diopter measurements.

[0027] In another embodiment of the present invention, the resolution measurement is based on the use of external sensor input. An example of this embodiment can be implemented using a smartphone as a display device. The attached system can then have known contact points and defined distances. When the attached system is physically connected to the phone, the touch points indicate the pixel locations of these touch points, which in turn are used in conjunction with the known distances between the points to calculate the display resolution and PPI.

[0028] In another embodiment of the invention, the optical system is attached to a display. The display presents images to the user. These images can be used for vision testing or as a means of measuring the refraction of the optical system. For example, the optical system can be the user's eye, and the refraction measurement can be the refractive correction required by the eye. The optical system introduces aberrations, in particular distortion aberrations, to the user. This causes the image to appear unclear and malformed. In the present invention, a method for solving image distortion by means of pre-distortion of the image on the display is proposed. The image is pre-distorted with a distortion opposite to the distortion introduced by the optical system, so that if viewed directly on the display it will appear distorted, while viewing through an optical system with inherent distortion will cause the image to appear sharp and without distortion. The main principle of pre-distortion is the spatially correlated image curvature calibrated based on the original system distortion map.

[0029] These and other objects and advantages will become apparent when the following detailed description is considered in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Current process of acquiring glasses;

[0031] Figure 2 Examples of suggestions for the process of obtaining glasses;

[0032] Figure 3 Examples of proposed business models;

[0033] Figure 4A An example of implementing display resolution measurement;

[0034] Figure 4B Another example of implementing display resolution measurement;

[0035] Figure 4C Another example of implementing display resolution measurement;

[0036] Figure 5 Example of implementing display resolution measurement;

[0037] Fig. 6A An example of image distortion correction;

[0038] Figure 6B Another example of image distortion correction;

[0039] Figure 6C Another example of image distortion correction.

[0040] Reference numerals

[0041] 100 Current list of steps to get glasses;

[0042] 200 Suggested steps for obtaining glasses;

[0043] 300 attached devices, such as personal view tracking;

[0044] 400 display devices, such as smart phones;

[0045] 430 user-adjustable to fit markings of attached device;

[0046] 500 Alternative attachment devices, such as insight devices;

[0047] 540 Input area for attaching device. DETAILED DESCRIPTION

[0048] The following detailed description is directed to certain specific embodiments of the present invention. However, the present invention can be embodied in many different ways as defined and covered by the claims and their equivalents. In the specification, the accompanying drawings are marked, wherein the same components are always marked with the same numerical symbols.

[0049] Unless otherwise stated in the specification or claims, all terms used in the specification and claims shall have the meaning commonly assigned to those terms by those skilled in the art.

[0050] Unless the context clearly requires otherwise, throughout the specification and claims, the words "include," "comprising," and similar expressions should be construed in an inclusive sense, and not in an exclusive or exhaustive sense; that is, in a sense, "including, but not limited to." Words using the singular or plural number also include the plural or singular number, respectively. In addition, when used in this application, the words "herein," "above," "below," and words of similar meaning shall refer to this application as a whole and not to any particular portions of this application.

[0051] In an embodiment of the present invention, a resolution measurement is performed on a display (e.g., a display of a smartphone). The user is asked to connect to the device used in the refraction or vision test. The user is then presented with a shape on the display that is identical in shape and aspect ratio to the attached device. The user then adjusts the size and position of the displayed shape until it matches the base contour of the connected device. Figure 4A -C shows an example of an implementation of this method. Figure 4A The device is shown attached to a smartphone display, the outline shape of the smartphone display appearing to the user being too large compared to the base to which the device is attached. Figure 4C The device is shown attached to a smartphone display whose profile shape presented to the user is too small compared to the base to which the device is attached. Figure 4BThe device is shown attached to a smartphone display, which presents the user with an outline shape that is the correct size for the base to which the device is attached. At that point, the user can indicate a match and then measure the size of the shape in pixels. Since the specifications of the device are well known, the display resolution (PPI – pixel density) can be calculated as follows:

[0052]

[0053] where d p is the final matching size of the displayed shape in pixels, which is taken from the shape drawn on the display, and D D It is the shape and size (in inches) of the base of a well-known device.

[0054] In another embodiment of the present invention, resolution measurement can be performed by using sensors rather than by user input. In a proposed implementation, the measuring device can be mounted on a frame that includes at least two touch points, or the device itself has at least two touch points embedded on itself. These contact points are made of a material that allows interaction with the touch screen. An example is to attach a rubber dome to a slightly conductive plastic frame. The touch points are then connected to a display that includes a touch screen (for example, like on a smartphone). The display then detects the two touch points and records the pixel value of each point. The distance between the points can then be calculated according to the following formula:

[0055]

[0056] Where (x 1、2 ,y 1、2 ) are the coordinates of touch points 1 and 2 detected on the screen. The PPI can then be calculated using the same formula as above, where D D is the distance between touch points on the device in inches. In another embodiment of the present invention, three or more touch points may be implemented so that resolution may be measured in more than one direction.

[0057] Figure 5 An example implementation of the proposed embodiment is shown. In this figure, the attachment device is held in a frame with two contact points. The distance between them is well known. The device with the frame and the touch points is then connected to a touch-enabled display. The display then detects the touch points and can determine the touched pixels. The process described above for calculating PPI can then be followed.

[0058] In another embodiment of the present invention, a method for aberration correction is proposed. In particular, distortion-type aberrations. The distortion is mapped in space, and the distortion map is used to create a pre-distorted image that presents a clear image to the user when viewed through a distorted optical device. The distortion map can be obtained by simulation or empirically. The simulation of the distortion map can be achieved by ray tracing or other computational methods (analytical or numerical). For example, the empirical mapping can be completed by observing lines at different distances through an optical device, displaying lines at different distances, and assigning a curvature to each line as a function of the distance from the center to obtain a straight line when observed through an optical system. In other embodiments, a grid or points can be used for mapping instead of lines, in which case the curvature is used to straighten the grid or create an array of equidistant points, respectively. In an example embodiment, the curvature will match the radius of the circle. In another embodiment, the curve will match the polynomial expansion of the function. A best fit can be performed to match the curvature as a function of the distance to the center. This in turn can be used to correct the image presented to the user through the optical device. In an example embodiment, for a centrally symmetric image, the distance measurement may be bidirectional (between two coaxial lines) rather than a single distance to the center. In a simplified embodiment, where the image presented is intended to be a linear bar, the curvature may be considered uniform for the entire bar based on, for example, the curvature of the center of the bar. This may simplify having to create different curvatures for the sides of the bar. This approximation works well if the bar thickness is small relative to the radius of curvature.

[0059] Fig. 6A -C shows an illustration of an example implementation of distortion correction. The figure uses two color bars as the displayed image. The image can be used to demonstrate distortion correction, as well as for use in the refractive measurement device of [PVT Patent]. The figure shows the image presentation on the display in the first row. The second and third rows show the two bars visible through the attachment device at two different locations along the bars on the display. The last row shows a situation where the lines appear to overlap through the attachment device. This is the case, for example, for 0D refraction. It shows the possible ambiguity of the overlapping situation required in the refractive measurement of [PVT Patent]. Fig. 6A The distortion present in the device is shown where the image on the display is expected without any correction through the system. The figure shows the fact that the straight lines on the display are equivalent to curved lines through the device optics. This will then cause errors and ambiguity to the user when viewing the image and performing a refraction test. Figure 6BA prior art form of controlling distortion in an image is presented. The solution used is to reduce the length of the bars to minimize the effect of the curvature of the lines caused by the distortion of the optical system. The disadvantage of this approach is obvious, as the curvature is not reduced, but only less noticeable. The shorter length of the lines causes many users to have problems viewing the lines and performing the test (aligning the bars). Figure 6C An embodiment of the solution of the invention is proposed in which the lines on the display are pre-distorted by the optics to produce a sharp image. The process described so far is used to construct a map of the curvature of the bars as a function of the distance between the bars to produce the straight line when it is viewed through the optics of the attached device (rows 2-4 in the figure).

[0060] The above detailed description of the embodiments of the present invention is not intended to be exhaustive or to limit the present invention to the precise form disclosed above. Although specific embodiments and examples of the present invention are described above for illustrative purposes, various equivalent modifications can be made within the scope of the present invention as will be appreciated by those skilled in the relevant art. For example, although steps are presented in a given order, alternative embodiments can perform routines with steps in different orders. The teachings of the present invention provided herein can be applied to other systems, not just the systems described herein. Various embodiments described herein can be combined to provide more embodiments. In view of the detailed description, these and other changes can be made to the present invention.

[0061] All of the above references and US patents and applications are incorporated herein by reference. Aspects of the invention can be modified, if necessary, to employ systems, functions, and concepts of the various patents and applications described above to provide further embodiments of the invention.

Claims

1. A method for measuring the refractive error of an optical system, the method comprising the following steps: a) using a first lens for reduction; b) using a second and a third lens, the second and third lenses each defining a slit; and wherein the second lens has a different color than the third lens; c) projecting a first line through first and second lenses using a viewing screen, and projecting a second line through first and third lenses using a viewing screen, wherein the first and second lines are pre-distorted to project relatively straight lines perceived by a user; d) rotating the first and second lines projected by the viewing screen using the meridian angle; e) initially placing first and second lines projected by the viewing screen using a first meridian angle, and adjusting the first and second lines to align using the optical system being tested to yield a first distance that the lines move for the first meridian angle; f) using a second meridian angle, the second meridian angle being a predetermined angular difference from the first meridian angle; adjusting the first and second lines so that the first and second lines are aligned to yield a second distance of line movement for the second meridian angle as perceived by the optical system being tested; g) Using the first and second distances the line is moved, in combination with the first and second meridian angles, to derive the refractive error of the optical system.

2. The method of claim 1 further comprising the step of projecting a viewing port marking (430) on the viewing screen; the user adjusting the viewing port screen to coincide with the viewing ports of the first and second lens lines.

3. The method according to claim 2, further comprising the step of calculating the pixel density PPI of the display screen by using the size of the view port screen specification adjusted by the user.

4. The method according to claim 2 further comprises calculating the pixel density PPI by the following formula: where d p is the final matching size of the displayed shape, which is taken from the shape drawn on the display screen, D D It is the shape and size of the base to which the device is attached.

5. A system for measuring a refractive error of an optical system, the system comprising: a) a first lens, which is used for reduction; b) a second and a third lens, wherein the second and the third lens each define a slit; and wherein the second lens has a different color than the third lens or has the same color as the third lens; c) a viewing screen for projecting the first line through the first and second lenses, and using the viewing screen to project the second line through the first and third lenses, wherein the first and second lines are pre-distorted to project relatively straight lines perceived by a user; d) rotating the first and second lines projected by the viewing screen using the meridian angle; e) a first meridian angle used to initially place first and second lines projected by the viewing screen and to adjust the first and second lines into alignment using the optical system being tested to yield a first distance that the lines move for the first meridian angle; f) a second meridian angle that is a predetermined angular difference from the first meridian angle; adjusting the first and second lines so that the first and second lines are aligned to yield a second distance of line movement for the second meridian angle as perceived by the optical system being tested; g) Using the first and second distances the line is moved, in combination with the first and second meridian angles, to derive the refractive error of the optical system.

6. The system of claim 5, further comprising a viewport marking (430) placed on the viewport screen; adjusting the viewport screen to coincide with the viewports of the first and second lens lines.

7. The system of claim 5, wherein the pixel density (PPI) is derived by using the size of the view port screen specification.

8. The system according to claim 6, wherein the pixel density PPI is obtained by the following formula: where d p is the final matching size of the displayed shape, which is taken from the shape drawn on the display screen, D D It is the shape and size of the base to which the device is attached.

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