Fundus camera and method of operating a fundus camera

Abstract

The techniques described herein are directed to fundus cameras, and more particularly, to fundus cameras having a display that projects an active vision alignment stimulus onto an eye of a subject via one or more components of an optical assembly. A fundus camera includes: an optical assembly including one or more optical components; a display adapted to project an active alignment pattern and a reference alignment pattern onto the eye of the subject via the optical assembly; a camera adapted to capture one or more images of the fundus of the subject; an eye tracker adapted to monitor the position of the subject's eye relative to the fundus camera; and a control system operatively coupled to the display, the camera, and the eye tracker and configured to direct the display to guide the subject toward pupil-to-camera alignment by dynamically adjusting the active alignment pattern relative to the reference alignment pattern based on the position of the subject's eye relative to the fundus camera. The active vision alignment stimulus is dynamically adjusted to guide the subject toward optical alignment for fundus imaging.

Description

[0001] This application is a divisional application of the patent application for invention titled "Active Visual Alignment Stimulation in Fundus Photography" with international application date of October 30, 2018, Chinese application number 201880071124.5.

[0002] Cross - reference to related applications

[0003] This application claims the benefit of and priority to U.S. Provisional Patent Application Serial No. 62 / 578,771, filed October 30, 2017, titled "Active Visual Alignment Stimulation in Fundus Photography", which is hereby incorporated by reference in its entirety. Technical field

[0004] This application relates to fundus cameras and methods of operating fundus cameras. Background art

[0005] Fundus photography involves using a specialized fundus camera to capture a photograph of the back of the eye, i.e., the fundus, through the pupil. Traditional fundus cameras typically include an optical assembly attached to a camera that enables a flash. The optical assembly consists of large, relatively expensive, and mechanically movable optics.

[0006] High - fidelity non - mydriatic fundus imaging requires optical alignment of the subject's eye with the optical assembly and the fundus camera. Optical alignment includes pupil - to - camera (or eyeball) alignment and angular (or fixation) alignment. Pupil - to - camera alignment axially and laterally aligns the subject's eye with the fundus camera in two dimensions. Similarly, angular alignment aligns the subject's eye and the optical assembly by adjusting tilt and pitch in order to image a particular structure or region of the fundus.

[0007] In wide - field fundus imaging, the alignment margin from the pupil to the camera is very small, such that achieving alignment typically requires a trained operator or a motorized stage. Similarly, angular alignment is difficult to achieve, in part because the size of the pupil is very small and constantly changing. For example, a young subject with deliberately dimmed eyes may have a relatively large pupil through which to image, while an older subject's pupil may not dilate as much. Additionally, in brighter ambient light conditions, the subject's pupil constricts, making it even more difficult to capture high - quality fundus images. Traditional angular alignment involves shining a fixation point onto the subject's eye and having the subject stare at the fixation point as intently as possible. Unfortunately, it is usually difficult and uncomfortable for the subject to focus on a single light point for an extended period of time. This level of intense focusing can and often does result in microsaccadic movements, such as unintentional back - and - forth eye movements, leading to inconsistent fixation. These movements and other problems with the traditional alignment process can result in unusable fundus images, such as images that do not capture the necessary field of view, including motion artifacts and the like.

[0008] According to one aspect of the present disclosure, there is provided a fundus camera, the fundus camera comprising: an optical assembly including one or more optical components; a display adapted to project an active alignment pattern and a reference alignment pattern onto the eye of a subject via the optical assembly; a camera adapted to capture one or more images of the fundus of the subject; an eye tracker adapted to monitor the position of the subject's eye relative to the fundus camera; and a control system operatively coupled to the display, the camera, and the eye tracker and configured to guide the display to direct the subject towards pupil-to-camera alignment by dynamically adjusting the active alignment pattern relative to the reference alignment pattern based on the position of the subject's eye relative to the fundus camera.

[0009] According to another aspect of the present disclosure, there is provided a method of operating a fundus camera, the method comprising: projecting an animated fixation target onto the eye of a subject via an optical assembly; emitting one or more flashes onto the eye of the subject via the optical assembly; capturing one or more images of the fundus of the subject using the fundus camera during the one or more flashes; and dynamically adjusting the animated fixation target within the fixation zone to promote dilation of the eye pupil while guiding the subject's line of sight towards fixation alignment.

[0010] According to another aspect of the present disclosure, there is provided a fundus camera, the fundus camera comprising: a display adapted to project an animated fixation target onto the eye of a subject via an optical assembly; a camera adapted to capture one or more images of the fundus of the subject; and a control system operatively coupled to the display and the camera and configured to guide the display to dynamically adjust the animated fixation target within the fixation zone to promote dilation of the eye pupil while guiding the subject's line of sight towards fixation alignment. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The detailed description is set forth and presented by reference to specific examples illustrated in the accompanying drawings. It should be understood that these drawings depict only typical examples and are not to be considered limiting of their scope, and the embodiments will be described and explained with additional features and details by using the drawings.

[0012] Figure 1A and 1B A block diagram depicting an exemplary schematic architecture of a fundus camera according to some embodiments, the fundus camera including a display for presenting an animated fixation target to the eye of a subject for fundus imaging.

[0013] Figure 2 A block diagram depicting example components of a fundus camera according to some embodiments.

[0014] Figure 3Depicted is a flow chart showing example operation of a fundus camera with a display in accordance with some implementations.

[0015] Figure 4A , 4B 4C depicts the progression of an example animated fixation target within a fixation zone of a viewing area for guiding or directing the subject's gaze toward alignment of fundus imaging, according to some embodiments.

[0016] Figure 5 Shown is the progression of another example animated fixation target within a fixation zone of a viewing area for guiding or directing the subject's gaze toward alignment of fundus imaging in accordance with some embodiments.

[0017] Figure 6A , 6B , 6C, 6D, 6E, and 6F describe the progression of another example animated gaze target within a gaze zone for directing or guiding the subject's gaze toward an aligned viewing area for fundus imaging, according to some embodiments.

[0018] Figure 7 An example is depicted in accordance with some embodiments where an animated fixation target is a visual field or acuity test within a fixation zone of a viewing area used to guide or direct the subject's gaze toward alignment of fundus imaging.

[0019] Figure 8 Depicted is a flow chart showing example operation of a fundus camera with a display in accordance with some implementations.

[0020] Figure 9 Depicted is a flow chart showing example operation of a fundus camera with a display in accordance with some implementations.

[0021] Figure 10 Depicted is an exemplary schematic architecture of a fundus camera including a visual feedback scheme for self-alignment according to some embodiments.

[0022] Figures 11A-11D Depicted is an exemplary active visual alignment stimulus projected onto the eyes of a subject within the field of view for directing or guiding the subject's gaze toward pupil-to-camera alignment in accordance with some embodiments.

[0023] Figure 12 Depicted is a flow chart illustrating example operation of a fundus camera having a display operable to project active visual alignment stimuli in accordance with some embodiments.

[0024] Figure 13A and 13BDepicts an exemplary active vision alignment stimulus according to some embodiments, which is continuously projected onto the eyes of a subject within the visual field for guiding or directing the subject's line of sight towards pupil alignment.

[0025] Figure 14 Depicts an exemplary active vision alignment stimulus according to some embodiments, which is projected onto the eyes of a subject within the field of view for guiding or directing the subject's line of sight towards optical alignment.

[0026] Figure 15 Depicts an exemplary schematic architecture of a fundus camera according to some embodiments, which includes a three-dimensional (3D) visual feedback scheme for self-alignment.

[0027] Figure 16A and 16B Depicts example depth alignment schemes using a 3D display in the case where the eye is too far or too close to the fundus camera, respectively, according to some embodiments.

[0028] The figures are not necessarily drawn to scale. Similarly, for the discussion of some embodiments of the present technology, some components and / or operations may be divided into different blocks or combined into a single block. Additionally, although the present technology may be modified into various modifications and alternative forms, specific embodiments have been shown by way of example in the figures and will be described in detail below. However, the intention is not to limit the technology to the specific embodiments described. Instead, the technology is intended to cover all modifications, equivalents, and alternatives falling within the scope of the technology defined by the appended claims. Detailed Description

[0029] Examples will be discussed in detail below. Although specific embodiments are discussed, it should be understood that this is for illustrative purposes only. Those skilled in the relevant art will recognize that other components and configurations may be used without departing from the spirit and scope of the subject matter of the present disclosure. Embodiments may include machine-implemented methods, computing devices, or computer-readable media.

[0030] The examples discussed herein relate to fundus cameras, and more specifically, to fundus cameras having one or more embedded or included displays that project active vision alignment stimuli onto the eyes of a subject, such as a patient, via one or more components of an optical assembly to guide the subject towards optical alignment for capturing a fundus image.

[0031] In some embodiments, the fundus camera includes a display that projects an animated fixation target (or other image) onto the eye of the subject via one or more components of the optical assembly. The animated fixation target is dynamically adjusted within the fixation zone (or perimeter) to provide comfort to the subject while gradually guiding or directing the subject's eye towards optical alignment of the subject's eye with the optical assembly for fundus imaging and the fundus camera.

[0032] In some embodiments, the fundus camera includes a tracking camera (or component) that can track the position and / or size of the pupil of the subject when the fixation target is dynamically adjusted. The output of the tracking camera is fed to an opportunistic alignment mechanism for determining the optimal time to trigger the fundus imaging process, e.g., for maximizing pupil size during the imaging process. For example, when the animated fixation target guides or directs the subject towards alignment, the tracking camera can continuously monitor the subject's retina to determine when alignment is achieved. Among other advantages, the fundus camera improves accuracy and fixation while reducing the time required for fundus image capture. In addition, the fundus camera does not require a separate fundus camera operator.

[0033] In some embodiments, the fundus camera can monitor the adaptation time and automatically increase the illumination if the response time is greater than a threshold. In this way, the fundus camera detects the "sweet spot", e.g., before the iris has adapted to the dark conditions but before the rod response begins. This function avoids triggering the chemical rod response, thereby minimizing discomfort to the subject.

[0034] In some embodiments, the tracking camera can track the pupil as it grows over time, and when the pupil has stopped growing but before dark adaptation begins, the control system can trigger the imaging process, e.g., trigger a flash and capture one or more fundus images during the flash. In some embodiments, regardless of the individual rate of change or maximum pupil size, the tracking camera can track the pupil size and triggering the imaging process once the threshold pupil size (e.g., 5 mm) is exceeded may be sufficient for fundus imaging.

[0035] In some embodiments, real-time (or near real-time) feedback is provided via the display for the subject to visualize their own fundus. The real-time feedback enables a "selfie mode" such that the subject can manually trigger the fundus imaging process. In addition, one or more camera status indicators can be displayed to the subject so that the subject remains focused and is not surprised by, e.g., a camera flash.

[0036] Among other benefits, the fundus cameras discussed herein increase dilation of the subject's pupil without the use of drugs and optimize the subject's fixation and stability during fundus imaging, while maintaining the subject's eye in a comfortable mesopic state using small, low-cost optics. In addition, the fundus cameras strategically trigger the image capture process at appropriate times and, in some cases, automatically. These improvements contribute, among other things, to a relatively low-cost, high-fidelity non-mydriatic fundus camera.

[0037] Figure 1A and Figure 1B FIGS. 100a and 100b are block diagrams depicting exemplary schematic architectures 100a and 100b of fundus cameras 110a and 110b, respectively, showing a display 130 for presenting an animated fixation target onto a subject's eye 105 for fundus imaging, according to some embodiments. Referring first to Figure 1A , fundus camera 110a includes an optical assembly 120, a display 130, an illumination source 140, a camera 150, and a control system 160. Additional or fewer components are possible.

[0038] Optical assembly 120 includes semi-reflective mirrors 125 and 126. As described above, conventional fundus cameras include relatively large, expensive, mechanically movable optics. In contrast, optical assembly 120 includes smaller, less expensive, fixed optics. Optical assembly 120 may be configured in the form of a cylindrical opto-mechanical tube that the subject can look into for fundus imaging. Although not shown, optical assembly 120 may include a housing.

[0039] Display 130 is operable to project an animated fixation target or other image onto retina R of subject's eye 105 via one or more components of optical assembly 120. The fixation target may be displayed or presented within a fixation zone (or perimeter) to guide or direct the subject's line of sight toward alignment for fundus imaging. Display 130 may be any small, high-resolution electronic display, such as an OLED, LCD, or a display capable of providing high contrast and color, having micromirrors on glass or silicon, designed for near-eye applications. In some embodiments, display 130 may be a microdisplay.

[0040] As Figure 1AAs shown in the example of , the display 130 communicates with the control system 160. The control system 160 directs the display 130 to dynamically adjust the image within the fixation zone (or perimeter) and / or adjust the fixation zone (or perimeter) itself to direct or guide the subject's line of sight towards fixation alignment. As discussed herein, the phrase "dynamically adjust the image" or variants thereof means slightly changing or moving the image to obtain a desired appearance on the display. Dynamic adjustment can also include adaptation of the image, e.g., from one image to another, various movements of the image, etc. For example, the image can be dynamically adjusted based on new inputs that were previously unknown, such as new inputs from an eye tracker.

[0041] The fixation target can be one or more objects or images strategically selected to maximize the dilation of the subject's pupil P and optimize the subject's fixation and stability during fundus imaging while keeping the subject's eyes in a comfortable mesopic state. In some embodiments, the fundus camera achieves an increase in pupil dilation of the subject's eye by presenting a pattern (or fixation target) having a specific modulation transfer function (MTF) or spatial frequency content. MTF is the spatial frequency response of an imaging system or its components.

[0042] In addition, the fixation target can be strategically selected to cause the subject to increase the focusing intensity (and / or other types of emotional arousal), which in turn maximizes the size of the pupil P for fundus imaging. For example, the control system 160 can control the intensity of each individual pixel of the display 130 in a manner that helps increase the size of the pupil P. The control system 160 can also direct the display 130 to change the ambient lighting conditions to cause the eye 105 to increase the focusing intensity and / or dilate the pupil P for fundus imaging. For example, the display can project a pure black background instead of a dark red background and / or change or vary the background as needed.

[0043] The illumination source 140 can be any light source that emits illumination light and / or otherwise provides light (or flash) for capturing a fundus image via the camera 150. As Figure 1A shown in the example of , the illumination light is projected onto the subject's eye 105 by one or more components of the optical assembly 120. The camera 150 can be any camera configured to capture an image of the fundus via the optical assembly 120. In some embodiments, the camera 150 can be a high-speed camera that enables multiple images or frames to be captured during an extended flash.

[0044] The control system 160 is operably coupled to various components of the fundus camera 110a to provide control information and / or receive feedback. As Figure 1AAs shown in the example of , the control system 160 is operably coupled to the display 130, the illumination source 140, and the camera 150. In some embodiments, the control system 160 monitors the gaze alignment and begins fundus imaging once the gaze alignment is achieved. For example, once the gaze alignment is suitably achieved, the control system 160 directs the illumination source 140 to emit a flash, and directs the camera 150 to capture a plurality of images during the flash.

[0045] In some embodiments, the illumination source 140 is configured to emit an extended flash, such as 100 - 200 milliseconds or longer, so that the camera 150 can capture a plurality of frames, such as 50 or more frames or images. It can be understood that although the flash is extended, a typical subject will not notice the difference between the extended flash and an instantaneous flash.

[0046] The speed of the camera 150 enables a high - speed imaging pipeline that facilitates capturing a plurality of images during the extended flash. In contrast, traditional fundus cameras emit a very bright instantaneous flash to capture a single fundus image from a slower camera. As described above, if the camera 150 happens to be misaligned during the image capture window, or if the subject's eye 105 moves, the image may end up with motion artifacts or aberrations, resulting in a blurry or unusable photo.

[0047] In some embodiments, the control system 160 can work in conjunction with the camera 150 to enable the high - speed imaging pipeline. The control system 160 performs various post - processing procedures on the images. For example, the control system 160 analyzes the frames obtained from the camera 150, stacks them together to correct any motion artifacts or aberrations, discards bad or unusable frames, automatically selects the best frames, and stacks the remaining images back together to form a composite image. The control system 160 can drive the display 130 to maintain an animated fixation target during the duration of the extended flash to keep the subject fixated, thus avoiding motion artifacts or aberrations during the imaging process.

[0048] In some embodiments, the control system 160 directs the camera 150 to provide real - time feedback to the display 130, such that the subject has a real - time (or near real - time) visualization of what images can be captured at any given time point. The real - time feedback can be provided to the display 130 through one or more components of the control system 160 and / or through a direct channel from the camera 150 to the display 130. In some embodiments, the real - time feedback allows the subject to manually trigger fundus imaging, such as in a self - portrait mode.

[0049] Control system 160 represents any processing, computing system, or other circuitry that retrieves and executes software suitable for performing a service or set of services to capture high-fidelity fundus images as discussed herein. Control system 160 can include one or more general-purpose central processing units, graphics processing units, application-specific processors, and logic devices, as well as any other type of processing device, combinations thereof, or variations thereof.

[0050] Next, referring to Figure 1B , Figure 1B , a block diagram depicting an exemplary schematic architecture of a fundus camera 110b according to some embodiments is shown, the fundus camera 110b including a display 130 for presenting an animated fixation target onto the eye 105 of a subject for retinal imaging. The fundus camera 110b includes Figure 1A many components of the fundus camera 110a of

[0051] but also includes a tracking camera 170. Figure 1B Tracking camera 170 can be any camera configured to continuously track and / or monitor the pupil P of the subject via one or more components of the optical assembly 120. For example, tracking camera 170 can use infrared (IR) to track the eye 105, such as the pupil P, retina R, etc. As shown in the example of

[0052] , tracking camera 170 tracks or monitors the pupil P via a semi-reflective mirror 127. Tracking information can be sent to the control system 160 to determine the exact time of achieving fixation alignment.

[0053] When the fundus camera 110b is attempting to achieve fixation alignment, for example, when the subject is staring down into the optical tube, tracking camera 170 visualizes the eye 105 in real time and control system 160 determines whether the subject is fixated correctly. In some embodiments, tracking camera 170 provides a continuous video stream of the subject's fixation. Control system 160 processes feedback information, such as the video stream, and directs the display 130 to project a fixation target to show the subject where and how to look.

[0054] In some embodiments, the display 130 provides a camera status indicator to the subject so that the subject knows when he or she is properly aligned or when the camera flash turns off, so that the subject is not startled. The camera status indicator can be a small graphic, color, etc., which is pre-determined to indicate the status of the fundus camera or the progress of alignment therewith.

[0055] In some embodiments, the fixation target can be animated strategically based on an opportunistic alignment mechanism. That is, when the opportunistic alignment mechanism determines that the subject is approaching alignment, the fixation target can be animatedly directed or guided to a final state, e.g., a single fixation point within the fixation zone that matches the final alignment. Alternatively, in some embodiments, the final state can include the fixation zone itself shrinking to a single fixation point. As discussed herein, the phrase "based on" means at least in part or in whole based on.

[0056] Figure 2 A block diagram depicting example components of a fundus camera 200 in accordance with some embodiments is shown. The fundus camera 200 can be Figure 1A the fundus camera 110a of Figure 1B or the fundus camera 110b of Figure 2 although alternative configurations are possible. As shown in the example of

[0057] , the fundus camera 200 includes a processor 210, a display 220, a speaker 230, an illumination system 240, a storage system 250, an input device 260, a tracking camera 270, a retinal camera 280, and a user experience (UX) display 290. Additional or fewer components are possible.

[0057] The processor 210 represents any processing, computing system, or other circuitry that retrieves and executes software from the storage system 250 that is adapted to perform a service or set of services that produce high-fidelity fundus images as discussed herein. For example, the processor 210 accesses, monitors, or otherwise receives inputs from other components of the fundus camera to control the components and provide. Examples of the processor 210 include a general-purpose central processing unit, a graphics processing unit, an application-specific processor, and a logic device, as well as any other type of processing device, combinations or variations thereof.

[0058] The display 220 represents any small, high-resolution electronic display designed for near-eye applications. As discussed herein, the display includes various components for presenting an animated fixation target to the subject and dynamically adjusting the animated fixation target.

[0059] The speaker 230 represents any auditory device capable of emitting sound to notify the subject about the internal state of the fundus camera (e.g., alignment, flash, etc.).

[0060] The illumination system 240 represents any light source that emits illumination light and / or otherwise provides a flash for capturing a fundus image via the retinal camera 280.

[0061] The memory 250 represents any storage system for storing operation instructions and a memory for the captured fundus images. The memory 250 can be any device, mechanism, or populated data structure for storing information. In some embodiments, the memory 250 can include any type, but not limited to, volatile memory, non-volatile memory, and dynamic memory. For example, the memory 250 can be random access memory, memory storage device, optical memory device, media magnetic medium, floppy disk, magnetic tape, hard disk drive, SDRAM, RDRAM, DDR RAM, erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), optical disc, DVD, etc. The memory 250 can include one or more disk drives, flash drives, one or more databases, one or more tables, one or more files, local cache memory, processor cache memory, relational database, flat database, etc. In addition, those of ordinary skill in the art will recognize many additional devices and techniques for storing information that can be used as the memory 250.

[0062] The input device 260 represents any device or other circuit that receives external input from the operator of the fundus camera and / or the subject. For example, the input device 260 can include a microphone, a clicker for triggering imaging, a keyboard, or other input devices.

[0063] The tracking camera 270 represents any camera, IR or near-IR tracking device (e.g., any wavelength above 820 nanometers), or image sensor capable of tracking the subject's eye. For example, the tracking camera 270 can use infrared (IR) to track and / or monitor one or more parts of the subject's eye. As discussed herein, the processor 210 can use the tracking information and / or video stream to determine the precise time to achieve fixation alignment. In addition, the IR video stream can be fed to the display 220 for real-time projection back to the subject.

[0064] The user experience (UX) display 290 represents any external monitor or touch screen for interacting with the fundus camera. In some embodiments, the operator of the fundus camera 200 can use the UX display 290 to visualize alignment, trigger fundus imaging, control the animated fixation target or other images (including video feedback) projected by the display 220, etc.

[0065] Figure 3 A flowchart depicting an example operation 300 of a fundus camera having a display is shown according to some embodiments. More specifically, Figure 3The example depicts the operation of a fundus camera that has a display for projecting an animated fixation target onto the eye of a subject for guiding or directing the subject's line of sight toward alignment for fundus imaging. Exemplary operation 300 may be performed in various embodiments by a fundus camera or one or more processors, modules, engines, or components associated therewith, such as fundus cameras Figure 1A or Figure 1B 110a or 110b of

[0066] First, at 301, the fundus camera directs the display to project a fixation target onto the subject's retina. At 303, the fundus camera dynamically adjusts the fixation target within the fixation zone to guide the subject's line of sight toward alignment for fundus imaging. Finally, at 305, once aligned and fixated, the fundus camera captures an image of the subject's fundus.

[0067] Figures 4A-4C Illustrates the progression of an exemplary animated fixation target 415 within a fixation zone Z of a viewing area V for guiding or directing a subject's line of sight toward fixation alignment for fundus imaging, according to some embodiments.

[0068] The viewing area V includes the field of view of the subject's eye when observing the opening of the fundus camera for retinal imaging. As Figures 4A-4C the example of

[0069] Figure 5 Illustrates the progression of another exemplary animated fixation target 515 within a fixation zone Z of a viewing area V for guiding or directing a subject's line of sight toward fixation alignment for fundus imaging, according to some embodiments.

[0070] As discussed herein, traditional fundus cameras use a fixation point (or dot) and require the subject to stare at the fixation point as intently as possible. However, the subject can only maintain his or her gaze for so long. As Figure 5 the example of

[0071] As Figure 5As shown in the example of , the animated fixation target (or image) 515 is a butterfly that flaps its wings, for example, as it flies around the fixation zone Z. The subject is asked to follow the trajectory of the fixation target 515 as it flies around the fixation zone Z and to decelerate and contract to the fixation point 516 where the image stops. Once the image stops, the subject's gaze is automatically attracted to that location, such as the fixation point, and the fundus camera images the eye.

[0072] Figures 6A-6F Shows the progression of another example animated fixation target 615 within the fixation zone Z of the viewing area V for guiding or directing the subject's line of sight towards fixation alignment for fundus imaging, according to some embodiments.

[0073] When subjects are fully engaged, their pupils tend to dilate. Therefore, the display can project the fixation target 615 with words or very small sentences that become smaller as it progresses towards the fixation point. This process tends to increase fixation or attention as the sentence contracts to the fixation point as the subject reads along. At a certain point, the image will stop contracting, and the fundus camera images the eye while the subject is reading very small printed words as attentively as possible.

[0074] FIG. 6 further shows an example of the gradual contraction of the fixation zone Z. In some embodiments, the animated fixation target 615 and / or the fixation zone can gradually shrink, causing the subject to focus intently on the fixation point.

[0075] Figure 7 Depicts an example according to some embodiments, where the animated fixation target is a visual field or acuity test 715 within the fixation zone Z of the viewing area V for guiding or directing the subject's line of sight towards fixation alignment for fundus imaging.

[0076] As mentioned above, when subjects are fully engaged, their pupils tend to dilate. In some embodiments, the animated fixation target can be a visual field or acuity test. In this case, the fixation target 715 can contract to the fixation point. Alternatively, the subject's line of sight can be tracked, and the smallest readable imprint can be the fixation point. In Figure 7 the example of , the letter "D" includes the fixation point.

[0077] In some embodiments, the fundus camera can be used to perform visual field or acuity tests as well as fundus imaging.

[0078] Figure 8 Depicts a flowchart of an example operation 800 of a fundus camera having a display, according to some embodiments. More specifically, Figure 8The example depicts the operation of a fundus camera that has a display for projecting an animated fixation target onto the eye of a subject for guiding or directing the subject's line of sight toward fixation alignment for fundus imaging. Exemplary operation 800 can be performed in various embodiments by a fundus camera or one or more processors, modules, engines, or components associated therewith, such as fundus cameras Figure 1A or Figure 1B 110a or 110b.

[0079] First, at 801, the fundus camera projects a fixation target onto the eye of the subject, such as onto the retina. At 803, the fundus camera dynamically adjusts the fixation target within the fixation zone to guide the subject's line of sight toward the fixation point. At 805, the fundus camera tracks or monitors the subject's line of sight. At decision 807, the fundus camera determines whether fixation alignment is detected. If not, the fundus camera continues to track the subject's line of sight. If so, then at 809, the fundus camera automatically captures an image of the subject's fundus.

[0080] Figure 9 FIG. depicts a flowchart of an exemplary operation 900 of a fundus camera having a display, in accordance with some embodiments. More specifically, Figure 9 the example depicts the operation of a fundus camera that has a display for projecting an animated fixation target onto the eye of a subject for guiding or directing the subject's line of sight toward fixation alignment for fundus imaging. Exemplary operation 900 can be performed in various embodiments by a fundus camera or one or more processors, modules, engines, or components associated therewith, such as fundus cameras Figure 1A or Figure 1B 110a or 110b.

[0081] First, at 901, the fundus camera projects a real-time video feed of the subject's retina onto the subject's retina. At decision 903, the fundus camera determines whether a trigger event is received, such as via a clicker. As discussed herein, in this implementation, the subject can use the fundus camera in a "selfie mode" If no trigger event is detected, the fundus camera continues to project the real-time video feed. However, if a trigger event is received, then at 905, the fundus camera fires a flash, captures an image of the subject's fundus, and stores the image in memory.

[0082] Figure 10 FIG. depicts an exemplary schematic architecture 1000 of a fundus camera 1010, in accordance with some embodiments, which includes a visual feedback scheme for self-alignment. As Figure 10As shown in the example of, the fundus camera includes a display 1030 that projects an active vision alignment stimulus onto the eye 1005 of the subject to facilitate pupil-to-camera alignment and / or fixation alignment for fundus photography.

[0083] The fundus camera 1010 includes an optical assembly 1020, a display 1030, an infrared (IR) light-emitting diode (LED) 1040, a camera 1050, a control system 1060, a tracking camera 1070, an illumination source 1075, a user interface (UI), and a display system 1080. Additional or fewer components are possible.

[0084] As Figure 10 As shown in the example of, the fundus camera 101 includes three imaging paths. The first imaging path shows the projection of an active vision alignment stimulus from the display 1030 onto the imaging eye 1005 of the subject via one or more components of the optical assembly 1020. More specifically, the display 1030 projects the active vision alignment stimulus onto the mirror 1025, and the mirror 1025 projects the active vision alignment stimulus onto the polarization beam splitter 1024 via the lens 1022b. The polarization beam splitter 1024 projects the active vision alignment stimulus onto the retina R of the eye 1005 via the lens 1022a. The second imaging path shows the tracking of the position of the eye 1005 by the tracking camera 1070. More specifically, the tracking camera 1070 tracks the position of the eye 1005 projected through the lenses 1022b, 1025, and 1022c via the lens 1022a. Finally, the third imaging path shows the imaging of the fundus by the camera 1050 through the lenses 1022a, the polarization beam splitter 1024, the polarizer 1027, and the lens 1022d.

[0085] The optical assembly 1020 includes lenses 1022a - 1022d, a field stop 1023, a polarization beam splitter 1024, a mirror 1025, and a polarizer 1027. In some embodiments, the fundus camera 1010 may be configured in the form of a handheld device, where the subject holds the fundus camera in front of the eye and manually moves the device and / or his or her head to align for fundus imaging. The handheld device may be a cylindrical opto-mechanical tube that the subject can view for self-imaging of the fundus. Alternatively, the fundus camera 1010 may be a desktop or wall-mounted device, in which case the user can adjust the head position or use a mechanical platform to align the camera.

[0086] The illumination source 1040 can be any light source that emits illumination light and / or otherwise provides light (or a flash) for capturing a fundus image via the camera 1050. As Figure 10As shown in the example of , the illumination light is projected onto the eye 1005 of the subject by one or more components of the optical assembly 1020. The camera 1050 can be any camera configured to capture an image of the fundus via the optical assembly 1020. In some embodiments, the camera 1050 can be a high-speed camera that enables multiple images or frames to be captured during an extended flash.

[0087] The display 1030 projects a visual alignment stimulus onto the retina R of the subject's eye 1005 via one or more components of the optical assembly 1020. The visual alignment stimulus can include an active alignment pattern that is dynamically adjusted relative to a reference alignment pattern based on the axial and lateral positions of the eye (i.e., axial displacement and two-dimensional lateral offset) to guide the subject towards pupil-to-camera alignment. Alternatively or additionally, the visual alignment stimulus can include an animated fixation target that is dynamically adjusted within the fixation zone to facilitate dilation of the pupil P while guiding or directing the subject towards fixation alignment. Various combinations or variations of the visual alignment stimulus are also possible.

[0088] The display 1030 can be any small, high-resolution electronic display, such as an OLED, LCD, or a display with micromirrors on glass or silicon designed for near-eye applications and capable of providing high contrast and color, etc. As Figure 10 shown in the example of , the display 1030 is placed in the conjugate plane of the retina R to visually guide the subject towards alignment. In some embodiments, the display 130 can be a microdisplay or have a display panel two inches or smaller.

[0089] The control system 1060 is operably coupled to various components of the fundus camera 1010 for providing control information to the components and / or receiving feedback from the components. As Figure 10 shown in the example of , the control system 1060 is operably coupled to the display 1030, the illumination source 1040, the camera 1050, the tracking camera 1070, the illumination source 1075, and the UI & display system 1080. The tracking camera 1070 can provide eye tracking position information or feedback to the control system 1060. The control system 1060 monitors the eye tracking position information or feedback and closes the feedback loop between the eye position and the active visual alignment stimulus. For example, the control system 1060 can guide the subject towards pupil-to-camera alignment and / or fixation alignment and determine when pupil-to-camera alignment and / or fixation alignment is achieved. In some embodiments, once pupil-to-camera alignment and / or fixation alignment is achieved, the control system 1060 can direct the illumination source 1040 to emit a flash and direct the camera 1050 to capture one or more images during the flash.

[0090] The tracking camera 1070 can be any camera or device that is operable to continuously track and / or monitor the position of the subject's eyes through one or more components of the optical assembly 1020. As Figure 10 shown in the example of, the tracking camera 1070 is operably coupled to the illumination source 1075. As discussed herein, the fundus camera 1010 can use any eye tracking technique that can measure the axial and lateral positions of the eye relative to the fundus camera 1010, preferably with an accuracy on the order of millimeters or better.

[0091] As described above, various techniques can be used to track the position of the subject's eyes. In some embodiments, the tracking camera 1070 can be an iris camera having an illumination source that includes infrared illumination. In this case, image-assisted eye tracking techniques can be used to determine the eye position. That is, the eye position can be measured from a video captured by the iris camera using real-time object tracking of the pupil and / or corneal reflection points. Using this technique, the center position of the pupil indicates the lateral position of the eye, and the relative position of the corneal reflection point indicates the axial position of the eye and the tilt of the pupil plane relative to the illumination source. However, as described above, any eye tracking technique capable of measuring the axial and lateral positions of the eye relative to the fundus camera 1010 can be utilized. For example, although not shown in the Figure 10 example of, in some embodiments, instead of the tracking camera 1070, an IR-illuminated retinal image or a direct camera view of the subject's eye 1005 can be used to track the position of the eye.

[0092] As Figure 10 shown in the example of, the tracking camera 1070 provides feedback to the control system, which in turn directs the display 1030 to dynamically adjust the visual alignment stimulus. For example, to guide the subject towards pupil-to-camera alignment, the active alignment pattern can be adjusted relative to a reference alignment pattern based on the position of the subject's eyes relative to the fundus camera. More specifically, the control system 1060 dynamically adjusts the active alignment pattern relative to the reference alignment pattern based on the position of the subject's eyes relative to the fundus camera to direct the display 1030 to guide the subject towards alignment. As discussed herein, the tracking camera 1070 monitors the position of the subject's eyes in real time (or near real time). In some embodiments, the tracking camera 1070 is operable to track the position of the subject's eyes at a frame rate greater than about 10 fps in order to provide real-time (or near real time) tracking.

[0093] Figures 11A-11D depicts an exemplary active visual alignment stimulus according to some embodiments that is projected onto the subject's eye within the field of view V for guiding or directing the subject's line of sight towards pupil-to-camera alignment. More specifically, Figures 11A-11DThe example of shows the active alignment pattern 1110, which is projected onto the eye of the subject and adjusted in real time (or near real time) relative to the reference alignment pattern 1120 based on the axial and lateral positions of the eye to guide or direct the subject towards pupil-to-camera alignment.

[0094] As Figures 11A-11D shown in the example of , the reference alignment pattern 1120 remains fixed at the center of the field of view V, while the active alignment pattern 1110 moves and changes size as the subject's eye moves relative to the camera. In some embodiments, the size of the active alignment pattern 1110 indicates the axial displacement of the subject's eye relative to the fundus camera. For example, when the subject's eye is farther away from the fundus camera, the active alignment pattern 1110 appears larger, and when the subject's eye is too close to the fundus camera, the active alignment pattern 1110 appears smaller. Alternatively or additionally, color can be used to indicate axial and / or lateral displacement.

[0095] In some embodiments, the subject is instructed to move the camera or his or her head to match the active alignment pattern 1110 with the reference alignment pattern 1120 in terms of size and position. As described above, the fundus camera dynamically moves or adjusts the active alignment pattern 1110 to the reference alignment pattern 1120 based on this movement. When the active alignment pattern 1110 and the reference alignment pattern 1120 overlap or fit together in a predetermined manner on the display, pupil-to-camera alignment is achieved. For example, as Figures 11A-11D shown in the example of , the active alignment pattern 1110 is circular, the reference alignment pattern 1120 is a cross, and the user is instructed to move the camera or his or her head to match the circle and the cross.

[0096] In some embodiments, once aligned, the camera automatically flashes and captures one or more images of the fundus. Figures 11A-11C The example of shows the process of guiding or directing the subject towards pupil-to-camera alignment. First refer to Figure 11A , the subject's eye is laterally off-center and axially too far away from the fundus camera. In Figure 11B , the subject's eye is laterally off-center and axially too close to the fundus camera. Similarly, in Figure 11C , the subject's eye is laterally centered but axially too far away from the fundus camera. Finally, Figure 11D shows the active alignment pattern 1110 and the reference alignment pattern 1120 overlapping or fitting together in a predetermined alignment manner.

[0097] It should be understood that in Figures 11A-11DIn an example, any pair of objects that are static relative to one another can be used. Alternatively, an arrow or other indicator can be used to indicate the direction and amount of movement. The color and size of the pattern can also be changed to indicate that the alignment is correct or to provide other signals / instructions. Additionally, since this active alignment stimulus is projected infinitely far onto the eye, in some embodiments, the stimulus can also be used as a fixation point for the subject. Similarly, the position of the fixation point in the display plane can be offset to guide the subject such that a camera, such as camera 1050, can image different regions of the retina.

[0098] Figure 12 Depicts a flowchart in accordance with some embodiments that illustrates an example operation 1200 of a fundus camera having a display operable to project an active visual alignment stimulus. More specifically, Figure 12 An example depicts an operation 1200 of a fundus camera having a display for projecting an active visual alignment stimulus to facilitate pupil-to-camera alignment and fixation alignment. Exemplary operation 1200 can be performed in various embodiments by a fundus camera or one or more processors, modules, engines, or components associated therewith, such as a fundus camera Figure 10 1010.

[0099] First, at 1201, the fundus camera adjusts the active alignment pattern relative to a reference alignment pattern based on the position of the subject's eye relative to the fundus camera. At decision 1203, the fundus camera determines whether pupil-to-camera (or eyebox) alignment has been achieved. If not, at 1201, the fundus camera continues to adjust the active alignment pattern relative to the reference alignment pattern. Otherwise, if pupil-to-camera alignment has been achieved, at 1205, the fundus camera dynamically adjusts the animated fixation target within the fixation zone to facilitate dilation of the eye pupil while guiding the subject's line of sight towards fixation alignment. At decision 1207, the fundus camera determines whether pupil-to-camera (or eyebox) alignment has been achieved. If not, at 1205, the fundus camera continues to adjust the animated fixation target within the fixation zone. Otherwise, if fixation alignment has been achieved, at 1209, the fundus camera captures one or more images of the subject's fundus and / or notifies or indicates that optical alignment was successful.

[0100] Figure 13A and 13B Depicts an exemplary active visual alignment stimulus in accordance with some embodiments that is continuously projected onto the subject's eye within the field of view V to guide or direct the subject's line of sight towards pupil alignment. More specifically, Figure 13A and 13B Illustrates an active visual alignment stimulus that is continuously projected onto the subject's eye to achieve pupil-to-camera alignment ( Figure 13A), followed by fixation alignment ( Figure 13B ).

[0101] First, referring to Figure 13A , Figure 13A depicts an active vision alignment stimulus, which includes an active alignment pattern 1310 and a reference alignment pattern 1320. As shown in the examples of Figure 13A and 13B , the active alignment pattern 1310 and the reference alignment pattern 1320 are images of a butterfly. The image of the butterfly can be static or appear to be moving (even while remaining in the same position), for example, by flapping its wings, etc.

[0102] As described above, the fundus camera monitors or tracks the position of the subject's eye in real time (or near real time) to dynamically adjust the active alignment pattern 1310 relative to the reference alignment pattern 1320 in real time (or near real time) based on the position of the subject's eye relative to the fundus camera, so as to guide or direct the subject towards pupil-to-camera alignment.

[0103] When the active alignment pattern 1310 and the reference alignment pattern 1320 match or overlap, pupil-to-camera alignment is achieved. At this time, as shown in the example of Figure 13B , fixation alignment occurs, and the active alignment pattern 1310 and the reference alignment pattern 1320 become a single animated fixation target 1315.

[0104] Figure 13B depicts the movement of the animated fixation target 1315 within the fixation zone Z of the viewing area V to guide or direct the subject towards fixation alignment. The fixation alignment technique discussed here improves fixation and helps to dilate the subject's eye pupil for fundus imaging.

[0105] As discussed herein, traditional fundus cameras use a fixation point (or dot) and require the subject to stare at the fixation point as intently as possible. However, the subject can only maintain his or her gaze for so long. As shown in the example of Figure 13B , the animated fixation target 1315 is displayed to the subject in a dim fixation window or area. The subject is required to observe the fixation zone Z, such as a window or a box. Advantageously, the fixation zone Z is relatively large compared to the dot used by traditional fundus cameras.

[0106] As Figure 13BAs shown in the example, the animated fixation target (or image) 1315 is a butterfly that, for example, is flapping its wings as it flies around the fixation zone Z. The subject is asked to follow the trajectory of the animated fixation target 1315 as it flies around the fixation zone Z and decelerate and contract to the fixation point 1316 where the image stops. Once the image stops, the subject's gaze is automatically attracted to that location, such as the fixation point, and the fundus camera images the eye.

[0107] The fundus camera can select the location of the fixation point 1316 in order to image a specific region of the retina. Although not shown, the process can be repeated (or looped) Figure 13B to image multiple different regions of the retina, for example, by selecting different fixation points.

[0108] Figure 14 Depicts an exemplary active vision alignment stimulus according to some embodiments that is projected onto the subject's eye within the field of view V to guide or direct the subject's line of sight towards optical alignment. Figure 14 The example of Figure 13A and 13B The example of, however, pupil-to-camera and angular alignment occur simultaneously.

[0109] Figure 15 Depicts an exemplary schematic architecture 1500 of a fundus camera 1510 according to some embodiments that includes a three-dimensional (3D) visual feedback scheme for self-alignment. As Figure 15 shown in the example of, by placing the active vision alignment stimulus at one focal length from the eyepiece (not shown), the active vision alignment stimulus can be displayed on the imaging eye 1005 and the non-imaging eye 1505 in a non-pupil-forming display scheme similar to a virtual reality (VR) headset. The fundus camera 1510 includes Figure 10 the components of the fundus camera 1010 of, but also includes an additional display 1530 and a lens 1522 for projecting the active vision alignment stimulus onto the non-imaging eye 1505. The lens 1522 can be a low-quality lens.

[0110] The fundus camera 1510 can use a stereoscopic display projected onto both eyes (imaging and non-imaging eyes) to achieve precise 3D alignment of the pupil of the imaging eye 1005 relative to the eye box of the camera. The operation of the fundus camera 1510 is discussed with reference to FIG. 16, which shows left and right displays projected onto the subject's imaging and non-imaging eyes, respectively.

[0111] In some embodiments, the left and right displays include two image objects: a static object 1620 and a moving object 1610 that moves with the position of the subject's imaged eye. Based on binocular disparity, each display (left and right) will be rendered to display the static object 1620 at a fixed point in the virtual 3D space, while the moving object 1610 moves in the virtual 3D space with the measured 3D position of the imaged eye 1005. When the imaged eye 1005 is aligned with the eye box of the camera, the objects are displayed at the same pixel positions on the display screen, and the subject perceives the virtual objects at the same positions in the virtual 3D space.

[0112] Figure 16A and 16B Examples of Figure 16A and 16B depict depth alignment schemes using 3D displays when the eye is too far or too close to the fundus camera, respectively. In some embodiments, the 3D display scheme provides a more immersive self-imaging experience than the monocular alignment scheme.

[0113] Certain inventive aspects can be understood from the foregoing disclosure, and various examples are provided below.

[0114] Example 1. A fundus camera, comprising: an optical assembly including one or more optical components; a display adapted to project an animated fixation target onto the subject's eye via the optical assembly; an illumination source adapted to emit one or more flashes onto the subject's eye via the optical assembly; a camera adapted to capture a plurality of images of the subject's fundus during the one or more flashes; and a control system operatively coupled to the display, the illumination source, and the camera and configured to direct the display to dynamically adjust the animated fixation target within the fixation zone to facilitate dilation of the eye pupil while guiding the subject's line of sight towards fixation alignment.

[0115] Example 2. The fundus camera of Example 1, wherein to dynamically adjust the animated fixation target within the fixation zone, the control system is configured to direct the display to gradually shrink the animated fixation target until the animated fixation target becomes a fixation point.

[0116] Example 3. The fundus camera of Example 1, wherein to dynamically adjust the animated fixation target within the fixation zone, the control system is configured to direct the display to gradually shrink the fixation zone until the fixation zone becomes a fixation point.

[0117] Example 4. The fundus camera of Example 3, wherein to gradually shrink the fixation zone, the control system is configured to maintain the relative position of the animated fixation target within the fixation zone.

[0118] Example 5. The fundus camera of Example 1, wherein the animated fixation target includes an image, a video, or one or more of one or more words, letters, or numbers.

[0119] Example 6. The fundus camera of Example 1, wherein the animated fixation target includes a visual field or acuity test.

[0120] Example 7. The fundus camera of Example 1, wherein the control system is configured to direct the display to project an animated fixation target for a preset duration, and wherein the animated fixation target includes one or more preset animations.

[0121] Example 8. The fundus camera of Example 1, wherein the control system is configured to direct the display to adjust the ambient lighting conditions during fixation alignment.

[0122] Example 9. The fundus camera of Example 1, wherein the control system is adapted to receive a real-time video feed from the camera and direct the display to project the real-time video feed onto the subject's eye.

[0123] Example 10. The fundus camera of Example 1, further comprising: an eye tracker adapted to monitor the subject's eye when the control system instructs the display to dynamically adjust the animated fixation target within the fixation zone based on the output of the eye tracker.

[0124] Example 11. The fundus camera of Example 10, wherein, in order to monitor the subject's eye, the eye tracker is adapted to track the position or size of the subject's pupil, and wherein the control system directs the display to dynamically adjust the animated fixation target within the fixation zone based on the position or size of the subject's pupil.

[0125] Example 12. The fundus camera of Example 10, wherein the eye tracker includes an iris camera and an infrared illumination source positioned to illuminate the subject's eye.

[0126] Example 13. The fundus camera of Example 10, wherein the control system is configured to determine that fixation alignment has been achieved based on the output of the eye tracker.

[0127] Example 14. The fundus camera of Example 13, wherein the control system, in response to determining that fixation alignment has been achieved, triggers the illumination source to emit one or more flashes and triggers the camera to capture a plurality of images of the subject's fundus.

[0128] Example 15. The fundus camera of Example 10, wherein the output of the eye tracker includes a real-time video feed, and the control system is configured to direct the display to project the real-time video feed onto the subject's eye.

[0129] Example 16. The fundus camera of Example 15, further comprising: a trigger mechanism adapted to receive an input from the subject, and wherein the control system is configured to direct the camera to capture a plurality of images of the subject's fundus in response to receiving the input.

[0130] Example 17. The fundus camera of Example 1, wherein the control system is configured to direct the display to project one or more camera status indicators onto the subject's eye.

[0131] Example 18. The fundus camera of Example 1, wherein the display is located within the image path at the conjugate plane of the retina.

[0132] Example 19. A fundus camera, comprising: an optical assembly including one or more optical components; a display adapted to project an animated fixation target via the optical assembly; an eye tracker adapted to monitor the eyes of a subject; and a control system operably coupled to the display and the eye tracker and configured to direct the display to dynamically adjust the animated fixation target within the fixation zone based on the output of the eye tracker to dilate the pupil of the eye while guiding the subject's line of sight towards fixation alignment.

[0133] Example 20. The fundus camera of Example 19, further comprising: an illumination source adapted to emit one or more flashes; and a camera adapted to capture a plurality of images of the subject's fundus during the one or more flashes.

[0134] Example 21. The fundus camera of Example 19, wherein for monitoring the eyes of the subject, the eye tracker is adapted to track the position or size of the subject's pupil.

[0135] Example 22. The fundus camera of Example 21, wherein the control system is configured to continuously monitor the degree or measure of alignment via the eye tracker.

[0136] Example 23. The fundus camera of Example 22, wherein the control system is configured to determine that alignment has been achieved when the degree or measure of alignment exceeds a predetermined threshold.

[0137] Example 24. The fundus camera of Example 22, wherein the control system is configured to dynamically adjust the animated fixation target within the fixation zone based on the degree or measure of alignment.

[0138] Example 25. A method, comprising: projecting an animated fixation target onto the eyes of a subject; dynamically adjusting the animated fixation target within the fixation zone to dilate the pupil of the eye while guiding the subject's line of sight towards fixation alignment; and capturing one or more images of the subject's fundus.

[0139] Example 26. The method of Example 25, further comprising: tracking the eyes of the subject while dynamically adjusting the animated fixation target within the fixation zone, wherein the animated fixation target is dynamically adjusted based on the tracking.

[0140] Example 27. The method of Example 26, wherein tracking the eyes of the subject includes obtaining tracking information including the position or size of the subject's pupil.

[0141] Example 28. The method of Example 27, further comprising: determining when alignment has been achieved based on the tracking information.

[0142] Example 29. The method of Example 28 further includes: automatically triggering the capture of a fundus image of the subject in response to determining that fixation alignment has been achieved.

[0143] Example 30. A fundus camera, comprising: an optical assembly including one or more optical components; a display adapted to project an active alignment pattern and a reference alignment pattern onto the eye of the subject through the optical assembly; a camera adapted to capture one or more images of the fundus of the subject; an eye tracker adapted to monitor the position of the subject's eye relative to the fundus camera; and a control system operatively coupled to the display, the camera, and the eye tracker and configured to direct the display to guide the subject toward pupil-to-camera alignment by dynamically adjusting the active alignment pattern relative to the reference alignment pattern based on the position of the subject's eye relative to the fundus camera.

[0144] Example 31. The fundus camera of Example 30, wherein the position that the eye tracker is adapted to monitor includes the axial displacement and two-dimensional lateral offset of the subject's eye relative to the fundus camera.

[0145] Example 32. The fundus camera of Example 31, wherein the eye tracker includes an iris camera and an infrared illumination source positioned to illuminate the subject's eye.

[0146] Example 33. The fundus camera of Example 31, wherein the control system is configured to dynamically adjust the size of the active alignment pattern to visually indicate the axial displacement of the subject's eye relative to the fundus camera.

[0147] Example 34. The fundus camera of Example 31, and wherein the control system is configured to dynamically adjust the two-dimensional position of the active alignment pattern on the display to visually indicate the two-dimensional lateral offset of the subject's eye relative to the fundus camera.

[0148] Example 35. The fundus camera of Example 31, wherein the control system is adapted to dynamically adjust the color of the active alignment pattern to visually indicate the axial displacement or two-dimensional lateral offset of the subject's eye relative to the fundus camera.

[0149] Example 36. The fundus camera of Example 31, wherein the control system is configured to: monitor the axial displacement and two-dimensional lateral offset of the subject's eye relative to the fundus camera to determine when pupil-to-camera alignment has been achieved, wherein when pupil-to-camera alignment is achieved, the active alignment pattern and the reference alignment pattern visually match in size and position on the display.

[0150] Example 37. The fundus camera of Example 36, wherein in order to match in size and position on the display, the active alignment pattern and the reference alignment pattern overlap or fit together in a predetermined manner.

[0151] Example 38. The fundus camera of Example 36, wherein the reference alignment pattern includes a cross, the active alignment pattern includes a circle, and when the edge of the cross is adjacent to the perimeter of the circle, the active alignment pattern and the reference alignment pattern visually match in size and position.

[0152] Example 39. The fundus camera of Example 36, wherein the control system is configured to trigger the illumination source to emit one or more flashes and trigger the camera to capture one or more images of the subject's fundus in response to a determination that alignment of the pupil to the camera has been achieved.

[0153] Example 40. The fundus camera of Example 30, wherein the reference alignment pattern includes a fixation target in the fixation area.

[0154] Example 41. The fundus camera of Example 40, wherein the control system is configured to direct the display to project the reference alignment pattern at different positions, and wherein each position corresponds to a different area of the subject's fundus.

[0155] Example 42. The fundus camera of Example 41, wherein the control system is configured to cycle between the respective positions to capture one or more images of the subject's fundus in each corresponding area.

[0156] Example 43. The fundus camera of Example 30, wherein the control system is configured to direct the display to dynamically adjust the animated fixation target within the fixation area to promote dilation of the eye pupil while guiding the subject's line of sight toward fixation alignment.

[0157] Example 44. The fundus camera of Example 43, wherein alignment of the pupil to the camera has been achieved prior to dynamically adjusting the animated fixation target within the fixation area to promote dilation of the eye pupil while guiding the subject's line of sight toward fixation alignment.

[0158] Example 45. The fundus camera of Example 44, wherein the reference alignment pattern becomes the animated fixation target when pupil-to-camera alignment is achieved.

[0159] Example 46. The fundus camera of Example 43, wherein alignment of the pupil to the camera is achieved while dynamically adjusting the animated fixation target within the fixation area to promote dilation of the eye pupil while guiding the subject's line of sight toward fixation alignment.

[0160] Example 47. The fundus camera of Example 46, wherein the active alignment pattern and the reference alignment pattern together form the animated fixation target and combine into a single pattern when pupil-to-camera alignment is achieved.

[0161] Example 48. The fundus camera of Example 30, further comprising: a second display adapted to project the active alignment pattern and the reference alignment pattern onto the non-imaging eye of the subject via an optical component, wherein the display and the second display are adapted to present the active alignment pattern and the reference alignment pattern in three-dimensional space based on binocular disparity.

[0162] Example 49. A fundus camera, comprising: an optical assembly including one or more optical components; a display adapted to project a visual alignment stimulus onto the eye of a subject via the optical assembly; an illumination source adapted to emit one or more flashes onto the eye of the subject via the optical assembly; a camera adapted to capture a plurality of images of the fundus of the subject during one or more flashes; an eye tracker adapted to monitor the position of the subject's eye relative to the fundus camera; and a control system operatively coupled to the display, the illumination source, the camera, and the eye tracker and adapted to direct the display to dynamically adjust the visual alignment stimulus, including: adjusting an active alignment pattern relative to a reference alignment pattern based on the position of the subject's eye relative to the fundus camera; and adjusting an animated fixation target within a fixation zone to promote dilation of the pupil of the eye while guiding the subject's line of sight toward fixation alignment.

[0163] Example 50. The fundus camera of Example 49, wherein the position that the eye tracker is adapted to monitor includes the axial displacement and two-dimensional lateral offset of the subject's eye relative to the fundus camera.

[0164] The functional block diagrams, operational scenarios and sequences, and flowcharts provided in the drawings represent exemplary systems, environments, and methods for performing the novel aspects of the present disclosure. Although the methods included herein may be in the form of functional diagrams, operational scenarios or sequences, or flowcharts for simplicity of explanation and may be described as a series of acts, it should be understood and recognized that these methods are not limited by the order of the acts, since some acts may occur in a different order and / or concurrently with other acts shown and described herein, depending on these acts. For example, those skilled in the art will understand and recognize that the methods may alternatively be represented as a series of related states or events, such as in a state diagram. Additionally, not all acts shown in the methods are required for the novel embodiments.

[0165] The descriptions and drawings included herein depict specific embodiments to teach those skilled in the art how to make and use the best selections. Some conventional aspects have been simplified or omitted to teach the principles of the invention. Those skilled in the art will recognize variations of these embodiments as falling within the scope of the present invention. Those skilled in the art will also understand that the above features may be combined in various ways to form multiple embodiments. Accordingly, the present invention is not limited to the above specific embodiments, but is defined only by the claims and their equivalents.

Claims

1. A fundus camera, comprising: an optical assembly including one or more optical components; a display adapted to project an active alignment pattern and a reference alignment pattern onto an eye of a subject via the optical assembly; a camera adapted to capture one or more images of the fundus of the subject's eye; an eye tracker adapted to monitor the position of the subject's eye relative to the fundus camera; and a control system operatively coupled to the display, the camera, and the eye tracker and configured to guide the display to direct the subject toward pupil-to-camera alignment by dynamically adjusting the active alignment pattern relative to the reference alignment pattern based on the position of the subject's eye relative to the fundus camera.

2. The fundus camera according to claim 1, wherein the position that the eye tracker is adapted to monitor includes an axial displacement and a two-dimensional lateral offset of the subject's eye relative to the fundus camera.

3. The fundus camera according to claim 2, wherein the control system is configured to: dynamically adjust the size of the active alignment pattern to visually indicate the axial displacement of the subject's eye relative to the fundus camera; or dynamically adjust the two-dimensional position of the active alignment pattern on the display to visually indicate the two-dimensional lateral offset of the subject's eye relative to the fundus camera; or dynamically adjust the color of the active alignment pattern to visually indicate the axial displacement or the two-dimensional lateral offset of the subject's eye relative to the fundus camera.

4. The fundus camera according to claim 2, wherein, the control system is configured to: monitor the axial displacement and the two-dimensional lateral offset of the subject's eye relative to the fundus camera to determine when pupil-to-camera alignment is achieved, wherein when pupil-to-camera alignment is achieved, the active alignment pattern and the reference alignment pattern visually match in size and position on the display.

5. A method of operating a fundus camera, comprising: projecting an active alignment pattern and a reference alignment pattern from a display onto an eye of a subject via an optical assembly including one or more optical components; monitoring the position of the subject's eye relative to the fundus camera using an eye tracker; dynamically adjusting the active alignment pattern relative to the reference alignment pattern based on the position of the subject's eye relative to the fundus camera, wherein the dynamic adjustment guides the subject toward pupil-to-camera alignment; and capturing one or more images of the fundus of the subject's eye using the camera.

6. The method according to claim 5, wherein the position monitored by the eye tracker includes an axial displacement and a two-dimensional lateral offset of the subject's eye relative to the fundus camera.

7. The method according to claim 6, further comprising: dynamically adjusting the size of the active alignment pattern to visually indicate the axial displacement of the subject's eye relative to the fundus camera; or dynamically adjusting the two-dimensional position of the active alignment pattern on the display to visually indicate the two-dimensional lateral offset of the subject's eye relative to the fundus camera; or dynamically adjusting the color of the active alignment pattern to visually indicate the axial displacement or the two-dimensional lateral offset of the subject's eye relative to the fundus camera.

8. The method according to claim 6, further comprising: Monitor the axial displacement and two-dimensional lateral offset of the subject's eye relative to the fundus camera to determine when pupil-to-camera alignment is achieved, wherein when pupil-to-camera alignment is achieved, the active alignment pattern and the reference alignment pattern visually match in size and position on the display.

9. A machine-readable medium storing instructions that, when executed by a control system of a fundus camera, will cause the fundus camera to perform operations, the operations including: Projecting an active alignment pattern and a reference alignment pattern from a display onto the subject's eye via an optical assembly including one or more optical components; Monitoring the position of the subject's eye relative to the fundus camera using an eye tracker; Dynamically adjusting the active alignment pattern relative to the reference alignment pattern based on the position of the subject's eye relative to the fundus camera, wherein the dynamic adjustment guides the subject towards pupil-to-camera alignment; and Capturing one or more images of the subject's fundus using a camera.

10. The machine-readable medium according to claim 9, wherein the position monitored by the eye tracker includes the axial displacement and two-dimensional lateral offset of the subject's eye relative to the fundus camera.

11. The machine-readable medium according to claim 10, wherein the operations further include: Dynamically adjusting the size of the active alignment pattern to visually indicate the axial displacement of the subject's eye relative to the fundus camera; or Dynamically adjusting the two-dimensional position of the active alignment pattern on the display to visually indicate the two-dimensional lateral offset of the subject's eye relative to the fundus camera; or Dynamically adjusting the color of the active alignment pattern to visually indicate the axial displacement or two-dimensional lateral offset of the subject's eye relative to the fundus camera.

12. The machine-readable medium according to claim 10, wherein the operations further include: Monitoring the axial displacement and two-dimensional lateral offset of the subject's eye relative to the fundus camera to determine when pupil-to-camera alignment is achieved, wherein when pupil-to-camera alignment is achieved, the active alignment pattern and the reference alignment pattern visually match in size and position on the display.

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