Patent ID: 12193748

DETAILED DESCRIPTION

In general terms, the present disclosure relates to reducing eye accommodation during vision screening. In one possible configuration, a chromatic aberration is displayed to reduce eye accommodation during capture of an optical image.

Eye accommodation is the mechanism by which the eye changes optical power to maintain a clear image or focus on an object as its distance varies. Distances vary from the far point, the maximum distance from the eye for which a clear image of an object can be seen, to the near point, the minimum distance for a clear image. Eye accommodation is achieved by the eye lens changing its shape. Children are able to accommodate their eyes more quickly, for a longer duration of time, and to a higher degree than older adults. This is because children typically have softer and more flexible eye lenses that can more easily accommodate.

FIGS.1and2illustrate cross-sectional views of an exemplary embodiment of a vision screening device100for conducting an ocular examination on an examinee. Components of the vision screening device100are identified and described with reference toFIG.1, whileFIG.2further illustrates a frame140enclosed within a housing150of the vision screening device100for supporting the components shown inFIG.1. In certain aspects, these components are similar to the components described in U.S. Pat. No. 9,237,846 issued on Jan. 19, 2016, the entirety of which is hereby incorporated by reference.

Referring toFIG.1, the vision screening device100includes optical and non-optical components. The optical components may include a lens component102coupled to an image capture component104, a light-emitting diode (LED) array106having visible LEDs106aand near-infrared (NIR) LEDs106b, a holographic diffuser108, and a beam-splitter110. The non-optical components may include a speaker105, a range finder112, an operator display screen114, and a front window116. It should be noted that vision screening device100is not limited to the foregoing listed components and may incorporate additional components, as needed.

The vision screening device100is preferably configured for mobility, but may also be suitable for stationary applications. Additionally, the vision screening device100may be wirelessly enabled to permit image data collection and analysis to be transmitted to a remote location for printing a report or to permit further assessment of an examinee's ocular response. For example, upon conducting an ocular examination using the vision screening device100, image data collected and corresponding results may be wirelessly transmitted and stored in a remote patient database configured for accessibility by authorized medical professionals.

The vision screening device100has functionality driven by a plurality of processes configured to assess ocular aspects of an examinee including, but not limited to, presenting attention-getting stimuli to the examinee, controlling an LED arrangement to irradiate pupils of the examinee, locating pupils of the examinee in captured images, displaying captured images to an operator, and analyzing pupil image data for determining refractive error and conducting related assessments. These processes may be performed by processing logic (not shown) under computer program control in the vision screening device100, which may be comprised of hardware (e.g., circuitry, dedicated logic, programmable logic, microcode, etc.), software (such as instructions run on a processing device), firmware, or a combination thereof.

Effective ocular screening of cooperative examinees, such as adults, and non-cooperative examinees such as children or animals, may be achieved through the use of the vision screening device100. The vision screening device100is configured to present attention-getting stimuli to an examinee. The presentation of attention-getting stimuli may be needed, particularly when screening non-cooperative examinees, in order to attract the examinees' direction of gaze. For proper ocular screening, the direction of gaze needs to be in the direction of lens component102coupled to image capture component104.

Various types of attention-getting stimuli may be utilized. In one example, an auditory stimulus may be used. The auditory stimulus may be a digitally recorded soundtrack under computer program control in the vision screening device100and may be presented, for example, via the speaker105. In another example, an unfocussed time-dynamic visual stimulus may be used. The visual stimulus may be presented through the use of colored LEDs provided, for example, by the LED array106. In some examples, the visual stimulus from the LED array106can be used to minimize an accommodative response from examinees. Additional locations may also be used to produce a chromatic blur to further reduce eye accommodation.

The visual stimulus may be comprised of an arrangement of differently colored LEDs. The arrangement of colored LEDs produce light in the visible spectrum below 600 nanometers to avoid contamination of near infrared (NIR) LED stimulus. This configuration allows the visual stimulus to be presented for attention getting purposes, but not to be seen in recorded images. The visible LED stimulus is independent of NIR LED stimulus and is not used in the data analysis associated with determining refractive error or gaze direction.

An example arrangement of the LED array106can include visible LEDs106athat are positioned between the NIR LEDs106band that are coplanar with NIR LEDs106b. Light emitted by visible LEDs106acan pass through the holographic diffuser108, creating diffuse stimuli, and is reflected towards the examinee by the beam-splitter110.

As with the auditory stimulus, the visible LEDs106amay also be under computer program control in the vision screening device100. More specifically, control parameters such as the intensity, duration, pattern, cycle time, and chromatic blur associated with the visible LEDs106amay be under computer program control. With respect to intensity, the visible LEDs106amust be regulated to be bright enough to attract the direction of an examinee, while at the same time being limited in brightness to avoid stimulating pupil constriction.

The duration of time in which the visible LEDs106aare turned on before being turned off is measured in milliseconds and is regulated based on the brightness of the visible LEDs106a. The visible LEDs106acan be arranged in a pattern appearing as three concentric rings. In this arrangement, the three concentric rings appear to the examinee as centered in the image capture component104of the vision screening device100. Each of the concentric rings may be comprised of more than one LED color spaced apart in a random pattern. A plurality of pattern combinations may be presented to an examinee in random order. The number of data frames collected prior to making a change to a pattern may also be regulated.

At least one objective of the control parameters associated with the visible LEDs106ais to present diffuse, random, and rapidly changing visible light patterns to an examinee. Such patterns can reduce, and in some cases may inhibit, accommodation of the examinee's eyes at a focal distance that is preferably set at one (1) meter from image capture component104. The focal distance can be determined using the range finder112.

Presentation of a visual stimulus need not be limited to the use of the visible LEDs106aarranged in the LED array106. In alternate examples, visual stimulus can be provided by an external source independent of the vision screening device100, an external source coupled to and under computer program control of the vision screening device100, or other suitable combinations thereof. Regardless of the attention-getting mechanism employed, an attention-getting stimulus is preferably presented continuously throughout an ocular examination.

As illustrated inFIG.3, light emitted from the LED array106is reflected by the beam-splitter110and transmitted in a direction202aalong the optical axis towards an examinee's eyes200. Light reflected back and exiting the examinee's eyes200is returned in a direction202band received at the image capture component104of vision screening device100. The light received by the image capture component104is used to generate images and data that can be analyzed to estimate the refractive error of the examinee's eyes200.

The ability for young children to more easily accommodate their eyes may result in inaccurate refractive error estimates because when the eyes of the examinee are accommodated, the eyes will appear to a vision screener as requiring no optical correction. An advantage of displaying an imitation of chromatic aberration by the vision screening device100is that it can trick the examinee's eyes to reduce and/or eliminate eye accommodation, and thereby improve the accuracy of the refractive error estimates determined by the vision screening device100.

FIG.4illustrates example chromatic aberrations402-410that can be displayed by the vision screening device100to mitigate eye accommodation during a vision acuity exam. The chromatic aberrations402-410are presented as fringes of color along boundaries that separate dark and bright areas of an image. An examinee will not be consciously aware of the effect of the chromatic aberrations402-410on their eyes. Instead, the chromatic aberrations402-410will be interpreted by the examinee's brain as a defocus error of their eyes, which causes the brain to reflexively adjust their eyes to accommodate and correct the defocus error.

The vision screening device100imitates chromatic aberration to cause the examinee's eyes to be tricked into focusing or defocusing. For example, a chromatic aberration402can be displayed as a blurred fringe of visible blue light that surrounds a blurred core of visible red light. In some examples, a blurred ring of visible green light is displayed between the blurred fringe of visible blue light and blurred core of visible red light. In certain examples, the chromatic aberration402can be displayed by the vision screening device100to stimulate an examinee's eyes to defocus inwardly closer to the infinity focus to reduce accommodation, and thereby improve refractive error estimates by the vision screening device100.

As another example, a chromatic aberration410can be displayed as a blurred fringe of visible red light that surrounds a blurred core of visible blue light. In some examples, a blurred ring of visible green light is displayed between the blurred fringe of visible red light and blurred core of visible blue light. The chromatic aberration410can be displayed by the vision screening device100to stimulate an examinee's eyes to focus outwardly.

The vision screening device100can display additional examples of chromatic aberrations404-408to produce a reflexive adjustment of an examinee's eyes, as desired. For example, a chromatic aberration404includes a blurred fringe of visible blue light that surrounds a blurred core of visible red light, and a blurred ring of visible green light between the blurred fringe of visible blue light and blurred core of visible red light. Thus, the chromatic aberration404is similar to the chromatic aberration402. The chromatic aberration404differs from the chromatic aberration402in that the blue, red, and green colors are less diffused (i.e., less blurry). Thus, the accommodative effect from the chromatic aberration404is less than the accommodative effect from the chromatic aberration402. As an illustrative example, the chromatic aberration402can produce an accommodative effective of −1.0 diopters, whereas the chromatic aberration404can produce an accommodative effective of −0.5 diopters.

A chromatic aberration408includes a blurred fringe of visible red light that surrounds a blurred core of visible blue light, and a blurred ring of visible green light between the blurred fringe of visible red light and blurred core of visible blue light. Thus, the chromatic aberration408is similar to the chromatic aberration410. The chromatic aberration408differs from the chromatic aberration410in that the blue, red, and green colors are less diffused. Thus, the accommodative effect from the chromatic aberration408is less than the accommodative effect from the chromatic aberration410. As an illustrative example, the chromatic aberration410can produce an accommodative effective of +1.0 diopters, whereas the chromatic aberration408can produce an accommodative effective of +0.5 diopters.

In some examples, the vision screening device100can display a chromatic aberration406that is neutral. For example, the chromatic aberration406does not cause an examinee's eyes to focus outwardly or defocus inwardly, but is rather displayed as an attention-getting stimulus. In some examples, the vision screening device100can transition back and forth between displaying various types of chromatic aberrations402-410during a vision acuity exam.

In some further examples, the vision screening device100can provide convergence control separate or in addition to mitigating eye accommodation during a vision acuity exam. Young children overlap images from each eye as a means to determine a distance to an object, and thereby to set a gaze angle to help with focusing and accommodating their eyes. The vision screening device100can display the chromatic aberrations402-410as separate objects that move relative to each other. In one example, the vision screening device100can display the chromatic aberrations402-410as separate objects that move toward each other, and that overlap or pass each other by. In further examples, the vision screening device100can display the chromatic aberrations402-410as alternating objects. Such techniques by the vision screening device100can provide additional effectiveness for accommodation control in younger children by causing eye focusing and accommodation further away from the device.

The chromatic aberrations402-410are displayed by an illumination component of the vision screening device100. In some embodiments, the illumination component includes one or more of the visible LEDs106athat generate the chromatic aberrations402-410which are reflected through the front window116and towards the examinee for viewing.

In alternative examples, the illumination component includes one or more of the visible LEDs106aand a light guide that disperses visible light from the one or more visible LEDs106aon the exterior of the housing150of the vision screening device100. The light guide disperses the visible light from the one or more visible LEDs106ato at least partially surround the exterior of the housing150, and thereby display the chromatic aberrations402-410. In some examples, the light guide disperse the visible light along the bottom of the housing150, along the sides of the housing150, along the top of the housing150, or entirely around the housing150.

In some examples, the light dispersed by the light guide around the exterior of the housing150is a blurred fringe of visible blue light. In some examples, one or more visible LEDs106adisplay a blurred core of visible red light through the front window116and towards the examinee, while the light guide disperses the blurred fringe of visible blue light around the exterior of the housing150to resemble the chromatic aberration402, and thereby to stimulate the examinee's eyes to defocus inwardly closer to the infinity focus.

In some further examples, the light dispersed by the light guide around the exterior of the housing150is a blurred fringe of visible red light. In some examples, one or more visible LEDs106adisplay a blurred core of visible blue light through the front window116and towards the examinee, while the light guide disperses the blurred fringe of visible red light around the exterior of the housing150to resemble the chromatic aberration410, and thereby to stimulate the examinee's eyes to focus outwardly.

In some further examples, the light dispersed by the light guide around the exterior of the housing150can transition back and forth between a blurred fringe of visible blue light and a blurred fringe of visible red light. Additional examples are contemplated. Thus, the visible LEDs106aare controllable to generate the chromatic aberrations402-410to reduce, and in some cases eliminate accommodation of the examinee's eyes to improve refractive error estimates determined from the images and data captured by the vision screening device100.

In addition, the vision screening device100can use the chromatic aberrations402-410produced by the visible LEDs106ato control and measure eye accommodation. The eye accommodation measurements can be used to diagnose and assess presbyopia, which is a gradual, age-related loss of the eyes' ability to focus actively on nearby objects. Thus, the vision screening device100can also be used to diagnose and measure presbyopia in older adults.

FIG.5illustrates another example of a vision screening device500that is configured in a manner similar to that of the vision screening device100. The vision screening device500includes a display unit502attached to the housing150by a pivot504. The display unit502can rotate about the pivot504to move from a stowed position to a deployed position. In some examples, the display unit502can be manually rotated about the pivot504such as by the hand of a user who is operating the vision screening device500. Alternatively, an electronic motor can be used to move the display unit502between the stored and deployed positions in response to a selection of a user input on the operator display screen114or elsewhere on the housing150.

InFIG.5, the display unit502is shown in the deployed position from the perspective of the examinee's eyes such that the front window116faces the examinee's eyes. In this illustrative example, the display unit502is attached to the top of the housing150. Alternatively, the display unit400can be attached to one of the sides or to the bottom of the housing150.

The display unit502includes a liquid-crystal display (LCD)506as the illumination component. When in the deployed position, the LCD506faces the examinee's eyes such that at least one of the chromatic aberrations402-410can be displayed on the LCD506for viewing by the examinee's eyes during a vision acuity examination to reduce eye accommodation.

The display unit502can display the chromatic aberrations402-410as separate objects that move relative to each other, and that possibly overlap or pass each other by. Alternatively, the display unit502can display the chromatic aberrations402-410as alternating objects. This can help produce focusing and accommodation further away from the device, and may provide convergence control and additional effectiveness for accommodation control.

FIG.6illustrates a method600of estimating refractive error of an examinee's eyes using the vision screening device100(or500). The method600includes an operation602of displaying a chromatic aberration, followed by an operation604of capturing an optical image, and followed by an operation606of estimating refractive error. In some examples, operations602-606are automatically performed when a user of the vision screening device100selects a predetermined workflow that is selectable by one or more user input on the operator display screen114or elsewhere on the housing150of the vision screening device100.

In operation602, displaying the chromatic aberration includes displaying at least one of the chromatic aberrations402-410shown inFIG.4, as described above. For example, operation602includes displaying the chromatic aberration402as a blurred fringe of visible blue light that surrounds a blurred core of visible red light to stimulate an examinee's eyes to defocus inwardly closer to the infinity focus, thereby reducing or eliminating eye accommodation.

In some examples, operation602includes displaying the chromatic aberration410as a blurred fringe of visible red light that surrounds a blurred core of visible blue light to stimulate an examinee's eyes to focus outwardly. In some further examples, operation602includes displaying one or more of the chromatic aberrations402-410, such that operation602can transition back and forth between displaying the chromatic aberrations402-410.

Operation602can be performed by any one of the configurations of the vision screening device100,500described above. For example, displaying the chromatic aberration in operation602can be performed by one or more of the visible LEDs106athat generate the chromatic aberration for viewing through the front window116. Alternatively, displaying the chromatic aberration in operation602can be performed by a light guide that disperses visible light generated from the one or more visible LEDs106ato at least partially surround the exterior of the housing150. In further examples, displaying the chromatic aberration in operation602can be performed by the LCD506attached to the housing150of the vision screening device500.

Operation604is performed by the image capture component104of the vision screening device100. The image capture component104captures one or more optical images. In some examples, the image capture component104captures a plurality of optical images.

The image capture component104can capture the optical images a predetermined period of time after the chromatic aberration is displayed in operation602. In some examples, the image capture component104captures the optical images simultaneously while the chromatic aberration is being displayed by the illumination component.

In examples where operation602transitions back and forth between displaying the chromatic aberrations402-410, operation604can include capturing a plurality of optical images during the transition, and tagging or time-stamping each captured optical image. The tags or time-stamps can be used to associate each captured image with the chromatic aberration402-410that was being displayed by the vision screening device100.

With respect to operation606, refractive error is defined as the optical correction that would provide good vision. Operation606can be performed according to any of the methods and techniques, including the use of algorithms, described in U.S. Pat. No. 9,237,846 issued on Jan. 19, 2016, and U.S. Pat. No. 9,408,535 issued on Aug. 9, 2016, the entireties of which are hereby incorporated by reference.

In examples where operation602transitions back and forth between displaying the chromatic aberrations402-410and operation604includes capturing a plurality of optical images during the transition, the method600can include an additional operation of determining a level of eye accommodation based on the captured plurality of optical images. For example, the ability of an examinee to accommodate their eyes based on the chromatic aberrations402-410that are displayed by the vision screening device100can be determined and quantified as a score that is displayed on the operator display screen114of the vision screening device100. In some examples, the score can be used to diagnose and assess presbyopia in older adult patients.

In some examples, the method600can include further operations of displaying the chromatic aberrations402-410as separate objects that move relative to each other. In one example, the method600can include displaying the chromatic aberrations402-410as separate objects that move toward each other, and that overlap or pass each other by. Alternatively, the method600can include displaying the chromatic aberrations402-410as alternating objects. These further operations can help produce eye focusing and accommodation further away from the vision screening device100, and can provide convergence control and additional effectiveness for eye accommodation control in younger children.

FIG.7schematically illustrates example components of the vision screening device100. The vision screening device500can be similarly configured. As shown inFIG.7, the vision screening device100has a processing device702, a system memory708, and a system bus720coupling the system memory708to the processing device702. The processing device702is an example of a processor such as a central processing unit (CPU). The processing device702is operatively connected to at least the image capture component104and the illumination component of the vision screening device100.

The system memory708is an example of a computer readable data storage device that stores software instructions that are executable by the processing device702. The system memory708includes a random-access memory (“RAM”)710and a read-only memory (“ROM”)712. Input/output logic containing the routines to transfer data between elements within the vision screening device100, such as during startup, is stored in the ROM712.

The vision screening device100can also include a mass storage device714that is able to store software instructions and data. The mass storage device714is connected to the processing device702through a mass storage controller (not shown) connected to the system bus720. The mass storage device714and its associated computer-readable data storage medium provide non-volatile, non-transitory storage for the vision screening device100.

Although the description of computer-readable data storage media contained herein refers to a mass storage device, it should be appreciated by those skilled in the art that computer-readable data storage media can be any available non-transitory, physical device or article of manufacture from which the device can read data and/or instructions. The mass storage device714is an example of a computer-readable storage device.

Computer-readable data storage media include volatile and non-volatile, removable and non-removable media implemented in any method or technology for storage of information such as computer-readable software instructions, data structures, program modules or other data. Example types of computer-readable data storage media include, but are not limited to, RAM, ROM, EPROM, EEPROM, flash memory or other solid-state memory technology, or any other medium which can be used to store information, and which can be accessed by the device.

The vision screening device100may operate in a networked environment using logical connections to remote network devices through the network20. The vision screening device100connects to the network20through a network interface unit704connected to the system bus720. The network interface unit704may also be utilized to connect to other types of networks and remote computing systems.

The vision screening device100can also include an input/output controller706for receiving and processing input from a number of input devices. Similarly, the input/output controller706may provide output to a number of output devices.

The mass storage device714and the RAM710can store software instructions and data. The software instructions can include an operating system718suitable for controlling the operation of the device. The mass storage device714and/or the RAM710also store software instructions716, that when executed by the processing device702, cause the device to provide the functionalities discussed in this document.

The various embodiments described above are provided by way of illustration only and should not be construed to be limiting in any way. Various modifications can be made to the embodiments described above without departing from the true spirit and scope of the disclosure.