Pathological and / or eye-side dependent illumination for retinal imaging

Abstract

To obtain a high-quality image. **Solution**: The retinal imaging system includes an eyepiece lens assembly, an image sensor adapted to obtain a retinal image of an eye through the eyepiece lens assembly, and a controller communicatively coupled to the image sensor. The controller, when executed, causes the retinal imaging system to obtain a point of interest (POI) related to the eye or an indicator of the laterality of the eye, select an eye box position for the eye box of the retinal imaging system based at least in part on the POI or the laterality of the eye, and obtain a retinal image of the eye when the eye is determined to be positioned within the eye box. The eye box corresponds to a boundary region within a space defined with respect to the eyepiece lens assembly.

Description

Technical Field

[0001] (Cross - Reference to Related Applications) This application claims the priority of U.S. Patent Application No. 63 / 345,258, filed on May 24, 2022, the content of which is incorporated herein by reference.

[0002] The present disclosure generally relates to retinal imaging technology, and specifically, although not exclusively, to lighting technology for retinal imaging.

Background Art

[0003] Retinal imaging is part of a basic eye examination for screening, in - field diagnosis, and progression monitoring of many retinal diseases. High - fidelity retinal images are important for accurate screening, diagnosis, and monitoring. Illuminating the inner surface of the back of the eye (i.e., the retina) through the pupil brightens the image, but if the retinal camera and the light source are not properly aligned with the eye, optical aberrations or image artifacts such as corneal reflections, iris reflections, lens flares, haze, or pupil shadows are often generated. Increasing the brightness of the illumination alone does not overcome these problems; rather, the optical artifacts become more prominent, and the goal of improving image fidelity is compromised.

[0004] Therefore, camera alignment is very important. Especially in conventional retinal cameras, since it is necessary to block the above - mentioned harmful image artifacts, typically, the eye box is limited. Referring to FIG. 1A, the eye box 100 of the retinal camera 105 is typically a boundary region within a three - dimensional space defined with respect to the eyepiece 110 of the retinal camera 105. In order to obtain an acceptable image of the retina, a specific part (e.g., the center) of the pupil 115 or the cornea of the eye needs to be present therein. Due to the small size of the conventional eye box, it is difficult to align the retinal camera, and the interaction with the patient during the alignment process often places a burden.

[0005] Conventional retinal camera systems (such as retinal camera 105) use a single eye box 100 having a single position (defined with respect to the eyepiece 110 of the camera system), from which both the left and right eyes are imaged. However, this single position is a compromise position that is not optimized for individual eyes, and further does not take into account the need to obtain higher quality images in specific regions of interest within the left and / or right eyes to assist a physician in screening, diagnosing, monitoring, or treating specific eye pathologies.

Brief Description of the Drawings

[0006] Non-limiting and non-exhaustive embodiments of the present invention are described with reference to the following figures, and like reference numerals refer to like parts throughout the various figures unless otherwise specified. Not all instances of elements are necessarily labeled so as not to clutter the drawings where appropriate. The drawings are not necessarily to scale, and instead emphasis is placed on illustrating the principles being described.

Figure 1A

Figure 1B

Figure 2A

Figure 2B

Figure 3A

Figure 3B

Figure 4

Figure 5

Figure 6

Figure 7A

Figure 7B

DETAILED DESCRIPTION OF THE INVENTION

[0007] Embodiments of an apparatus, a system, and an operating method for a retinal imaging system that adapts an eye box position based on a pathological lesion (POI) and / or eye laterality are described herein. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the embodiments. However, one of ordinary skill in the art will recognize that the techniques described herein may be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown in detail or described in order to avoid obscuring certain aspects.

[0008] Throughout this specification, the phrase "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0009] High-fidelity retinal images are important for the screening, diagnosis, and monitoring of many retinal diseases. For this purpose, it is desirable to reduce or eliminate instances of image artifacts that occlude or otherwise harm portions of the retinal image. This can be particularly applicable when a particular region of interest in a particular eye (e.g., the right or left eye) needs to be clearly imaged for screening, diagnosing, monitoring, or treating a particular eye lesion. Conventional retinal imaging systems use an eye box at a fixed eye box position that is fixed not only for a given eye but also across both the left and right eyes.

[0010] Figures 2A and 2B show exemplary retinal images of the left eye 200 and the right eye 201 (when viewed from the perspective of a physician or a retinal imaging system). As seen in FIGS. 2A and 2B, the anatomical features (e.g., the macula 205, the fovea 210, the optic nerve head 215, the retinal venules 220, and the retinal arterioles 225) are inverted about the vertical axis, changing the relative arrangement of these anatomical features between each eye 200 and 201. Thus, the important anatomical features in each eye 200 or 201 have different arrangements depending on the laterality of the eye. If high-quality images of specific anatomical features are desired, the optimal eye box position and illumination pattern may not be the same between each eye 200 and 201. Similarly, different lesions require good visualization of different parts of the eye. For example, the diagnosis and treatment of diabetic retinopathy are well performed by good visualization of the macula 205, and the diagnosis and treatment of glaucoma are well performed by good visualization of the optic nerve head 215. Thus, retinal imaging for the purpose of screening, diagnosing, monitoring, and treating ophthalmic lesions can also be assisted by adjusting the eye box position and illumination pattern based on the POI to ensure the best possible image of the relevant retinal area.

[0011] The desirability of a dynamically selected inbox position and / or illumination pattern is further emphasized by FIG. 2A. As illustrated, retinal imaging can be subject to a plurality of image artifacts including reflections 230, pupil shadows 235, haze 240, or others. These image artifacts can occur when stray light and harmful reflections from the illumination source enter the imaging path due to being smaller than the optimal alignment between the retinal imaging system and the eye, and ultimately when captured by the image sensor with retinal image light. Misalignment (or non-optimal alignment) can lead to harmful corneal / iris reflections, refractive scattering from the lens, occlusion of the imaging aperture, optical aberrations due to off-axis passage through the lens, blocking of the imaging light by the iris, and / or other problems. If these image artifacts occlude regions of interest particularly relevant to the screening, diagnosis, or treatment of the POI, the disease may go undetected or be inappropriately treated. Thus, by selectively positioning the inbox and customized illumination pattern based on the eye's laterality and / or the POI, these artifacts can be placed in less relevant positions and / or the retinal image can be improved by completely reducing or removing the artifacts. In some cases, the inbox position that achieves 100% removal of the image artifacts may not be easily or readily achievable. In such cases, a dynamic fixation target that uses a plurality of different illumination patterns to prompt the eye to move to a plurality of different inbox positions can prompt the patient's eye to rotate or align in a plurality of different directions / positions. Certain image artifacts may not be completely removed from all or any of the plurality of retinal images, but the patient's eye is instructed to rotate / move such that each region of interest of the retina is clearly imaged in at least one retinal image. The plurality of retinal images can then be combined or stacked to completely remove the image artifacts from the composite retinal image, at least in the regions of interest related to the eye's laterality and / or the POI.

[0012] Figures 3A and 3B show moving the eye box of the retinal imaging system 300 to different positions according to the laterality of the eye and / or the POI, according to an embodiment of the present disclosure. As shown, retinal imaging of the right eye can be well provided using an eye box 301 that is offset to the left (e.g., shifted 1.5 mm to the left from the center), while retinal imaging of the left eye can be well provided using an eye box 302 that is offset to the right (e.g., shifted 1.5 mm to the right from the center). These eye laterality offsets can improve the visualization of important anatomical features. This selective adjustment of the eye box position can also be indexed to the POI (or a combination of the POI and eye laterality) when the examination of a particular retinal region is of particular interest for screening, diagnosing, and treating a given eye lesion. Figures 3A and 3B show the eye boxes 301 and 302 using a cube or rectangle, but it should be understood that the eye box can assume various different three-dimensional shapes (e.g., spherical, elliptical, etc.).

[0013] Figure 4 shows a retinal imaging system 400 that can use a dynamic eye box position based on the POI and / or the laterality of the eye, according to an embodiment of the present disclosure. The illustrated embodiment of the retinal imaging system 400 includes an illuminator 405, an image sensor 410 (also referred to as a retinal image sensor), a controller 415, a user interface 420, a dynamic fixation target 425, an alignment tracking camera system 430, and an optical relay system. The illustrated embodiment of the optical relay system includes lens assemblies 435, 440, 445, and a beam splitter 450. The lens assembly 435 may also be referred to as an eyepiece lens assembly 435. The illustrated embodiment of the illuminator 405 includes a dynamic ring illuminator with a central aperture 455. The illustrated embodiment of the dynamic fixation target 425 includes a display 426 that outputs a dynamic fixed image 427 that may include one or more reference markers 428 representing the relative eye box and / or eye position.

[0014] The optical relay system directs (e.g., passes or reflects) the illumination light 480 output from the illuminator 405 along an illumination path through the pupil of the eye 470 to illuminate the retina 475, while directing the image light 485 (i.e., the retinal image) of the retina 475 along an imaging path to the image sensor 410. The image light 485 is formed by the scattered reflection of the illumination light 480 from the retina 475. In the illustrated embodiment, the optical relay system further includes a beam splitter 450, which passes at least a portion of the image light 485 to the image sensor 410 while optically coupling the dynamic fixation target 425 to the eyepiece lens assembly 435 to direct the dynamic fixation image 427 output from the display 226 to the eye 470. The beam splitter 450 can be implemented as a polarizing beam splitter, a non-polarizing beam splitter (e.g., 90% transmission and 10% reflection, 50 / 50 beam splitter, etc.), a multilayer dichroic beam splitter, or others. The optical relay system includes several lenses such as lenses 435, 440, and 445, and focuses on various optical paths as needed. For example, the lens 435 may include one or more lens elements that collectively form an eyepiece lens assembly that is displaced from the cornea of the eye 470 by the eye relief 495 during operation. The lens 440 may include one or more lens elements for focusing the image light 485 onto the image sensor 410. The lens 445 may include one or more lens elements for focusing the dynamic fixation image 427. It should be understood that the optical relay system can be implemented using a large number and variety of optical elements (e.g., lenses, reflective surfaces, diffractive surfaces, etc.) and may differ from the configuration shown in FIG. 4.

[0015] In one embodiment, the dynamic fixation image 427 output from the display 426 represents a fixation point at which the patient can adjust their focus and fixate their line of sight. The dynamic fixation image 427 may be an image of a plus sign, bull's eye, cross, target, circle, or other shape or collection of shapes (see, for example, FIGS. 7A and 7B). In the illustrated embodiment, the dynamic fixation target 425 is implemented as a virtual image output from the display 426. However, the fixation point may be implemented in a variety of other ways, including physical target(s) (which may be plural) that are actuated or optically manipulated. The dynamic fixation target 425 can help obtain alignment between the retinal imaging system 400 and the eye 470 by providing visual feedback to the patient, and can also provide the patient with a fixation point / fixation target at which the patient can adjust and stabilize their vision. The dynamic fixation target can be moved by translating an image of a fixation target (e.g., reference marker 428) around the display 426 as needed (e.g., moving a symbol or image up / down or left / right on the display 426). The display 426 can be implemented in a variety of technologies, including liquid crystal displays (LCDs), light emitting diodes (LEDs), various illuminated shapes (e.g., illuminated cross or concentric circles), or others. Of course, the dynamic fixation target can be implemented in ways other than as a virtual image on a display. For example, the dynamic fixation target can be a physically manipulated physical object (e.g., a crosshair, etc.).

[0016] The controller 415 is coupled to the image sensor 410, the display 426, the illuminator 405, and the alignment tracking camera system 430 to integrate their operations. The controller 415 can include software / firmware logic executed on a microcontroller, hardware logic (e.g., application-specific integrated circuit, field-programmable gate array, etc.), or a combination of software and hardware logic. FIG. 4 shows the controller 415 as different functional elements, but the logical functions executed by the controller 415 can be distributed across several hardware elements. The controller 415 can further include an input / output (I / O) port, a communication system, or others. The controller 415 is coupled to the user interface 420 to receive user input and provide user control for the retinal imaging system 400. The user interface 420 can include one or more buttons, dials, joysticks, feedback displays, indicator lights, etc.

[0017] The image sensor 410 can be implemented using various imaging technologies such as a complementary metal-oxide semiconductor (CMOS) image sensor, a charge-coupled device (CCD) image sensor, or others. In one embodiment, the image sensor 410 includes an on-board memory buffer or an attached memory for storing / buffering retinal images. In one embodiment, the image sensor 410 may include an integrated image signal processor (ISP) to enable high-speed digital processing of the retinal images buffered in the internal memory. The on-board image buffer and ISP can facilitate high frame rate image burst capture, image processing, image stacking, and output of high-quality synthetic retinal images. The integrated ISP may be regarded as a decentralized component of the controller 415.

[0018] The alignment tracking camera system 430 operates to track the lateral alignment (or misalignment) and relief offset between the retinal imaging system 400 and the eye 470, particularly between the eyepiece lens assembly 435 and the eye 470. The system 430 can operate using a variety of different techniques to track the relative placement of the eye 470 with respect to the retinal imaging system 400, including pupil tracking or iris tracking. In the illustrated embodiment, the system 430 includes two cameras positioned on either side of the eyepiece lens assembly 435 to enable triangulation and obtain X, Y, and Z overall placement information regarding the pupil or iris. In one embodiment, the system 430 also includes one or more infrared (IR) emitters to track the eye 470 using IR light while a retinal image is being acquired using a burst of visible spectrum light output from the illuminator 405 through the eyepiece lens assembly 435. In such an embodiment, an IR filter can be positioned within the image path to filter the IR tracking light. In some embodiments, the tracking illumination is temporarily offset from the image acquisition by the white light burst.

[0019] The lateral eye alignment may be measured by the system 430 via the retinal image acquired by the image sensor 410 or separately / additionally. In the illustrated embodiment, the system 430 is positioned externally to view the eye 470 from outside the eyepiece lens assembly 435. In other embodiments, the system 430 may be optically coupled using optical relay components to view and track the eye 470 through the eyepiece lens assembly 435.

[0020] FIG. 5 shows a dynamic ring illuminator 500 for illuminating the retina 475 during retinal imaging, according to one embodiment of the present disclosure. The dynamic ring illuminator 500 represents one possible implementation of the illuminator 405. The illustrated embodiment of the dynamic ring illuminator 500 includes a ring of light sources 505 surrounding a central aperture 510, which is also surrounded by a baffle 515 (e.g., a cone, a light shade, etc.) that blocks stray or off-axis light. The light sources 505 are arranged around the central aperture 510 with various radial and axial offsets. The light sources 505 can be independently actuated by the controller 415 to emit a selective illumination pattern. These patterns may be selected based on the eye's placement relative to the eyepiece 435 as determined by pupil / iris tracking using the system 430 or retinal tracking using the image sensor 410. The patterns may also be selected according to the laterality of the eye and / or the POI. In the illustrated embodiment, each light source 505 includes two emitters, namely, a white light emitter for color retinal images and an IR emitter for IR images. Since the human eye responds little or not at all to IR light, the IR emitter may be used for gaze tracking and acquisition of a preliminary image (e.g., determination of the laterality of the eye) before acquiring a full-color burst image. The white light emitter may burst white light for hundreds of milliseconds, enabling acquisition of a sequence of full-color images before the physiological response causes blinking and / or excessive pupil constriction.

[0021] Referring to FIG. 4, during operation, the controller 415 operates the illuminator 405 and the retinal image sensor 410 to capture one or more retinal images. The illumination light 480 is directed to pass through the pupil of the eye 470 to illuminate the retina 475. The scattered reflections from the retina 475 are directed back through the aperture 455 along the image path to the image sensor 410. When the eye 470 is properly aligned within the selected eye box of the system 400, the aperture 455 operates to block harmful reflections and light scattering that could otherwise adversely affect the retinal image while allowing the image light itself to pass through. Prior to capturing the retinal image, the controller 415 operates the display 426 to output a dynamic fixation image 427 for guiding the patient's line of sight. One or more initial or preliminary eye images (e.g., initial alignment images) from either the image sensor 410 or the alignment tracking camera system 430 are acquired and analyzed to determine the lateral alignment between the eye 470 and the eyepiece lens assembly 435. These initial alignment images can be illuminated with infrared (IR) light output from the illuminator 405 (or an independent illuminator associated with the alignment tracking camera system 430) so as not to trigger the iris constriction response that narrows the imaging path to the retina 475. In other embodiments, conventional white light or other colored light is used to acquire the initial alignment images. The initial alignment images are then analyzed by the controller 415 to identify any misalignment, relocate the eye position reference within the dynamic fixation image 427 to prompt proper eye positioning with respect to the selected eye box, and then trigger the acquisition of one or more subsequent eye images (e.g., retinal image bursts) by the image sensor 410. The subsequent images can be full-color images, specific color images, or IR images, as needed.

[0022] FIG. 6 is a flowchart showing a process 600 for capturing a retinal image using a dynamic eye box position, a fixation target, and an illumination pattern based on eye laterality and / or a cardiac lesion, according to an embodiment of the present disclosure. The order in which some or all of the process blocks appear in process 600 should not be considered limiting. Rather, those skilled in the art having the benefit of this disclosure will understand that some of the process blocks may be executed in various orders not illustrated, or even in parallel.

[0023] In process block 605, the retinal imaging process is initiated. Initiation may include the user pressing a power button on the user interface 420. After power-on, the controller 415 obtains an indicator of the POI associated with the eye being examined. This indicator may be requested via the user interface 420 or may be input by the user / operator of the retinal imaging system 400. Exemplary POIs may include diabetic retinopathy, glaucoma, or others. Based on the determination of a particular POI, the controller 405 can configure the eye box position and / or illumination pattern to best examine the portion(s) of the retina 475 most relevant to the particular ophthalmic disease selected.

[0024] In process block 615, illumination is enabled to obtain a preliminary eye image, facilitate eye tracking, and / or determine eye laterality. In one embodiment, this initial illumination is IR illumination output from the alignment tracking camera system 430 and / or the IR emitter of the light source 505. The IR illumination reduces the likelihood of causing a physiological response that contracts the iris before light is used to acquire the primary retinal image.

[0025] In process block 620, the eye laterality (i.e., right or left eye) is determined. The eye laterality may be manually input via the user interface 420, or automatically determined by the controller 415 based on image analysis and feature identification performed on a preliminary image of the eye. The preliminary image may be an IR retinal image acquired via the image sensor 410 and / or an eye image acquired by the alignment tracking camera system 430.

[0026] Once one or both of the eye laterality and the POI are determined, the eye box position of the retinal imaging system 400 can be selected (process block 625). The determination may be based on either or both of these factors. The eye box position is the position of the eye box of the imaging system and is a boundary region within the space defined relative to the eyepiece assembly. As shown in FIGS. 3A and 3B, the eye box position for the right eye is generally offset to the left (e.g., offset about 1.5 mm to the left), while the eye box position for the left eye is generally offset to the right (e.g., offset about 1.5 mm to the right). The identification of a particular POI can be used to further refine this eye box position in addition to the eye-side default. For example, the identification of diabetic retinopathy will translate the eye box position to center the retinal image over the macula 205 on the given eye side, and the identification of glaucoma will translate the eye box position to center the retinal image over the optic nerve head 215 on the given eye side. Of course, depending on the POI, other translations and focusing on the position of the eye may be appropriate. Additionally (or alternatively), these lesion-based offsets serve to move image artifacts away from the retinal region of interest as determined based on the POI.

[0027] When an iBox position is selected, the fixation position of the dynamic fixation target 425 can be configured to prompt the eye 470 to adjust its placement and / or line of sight accordingly (process block 630). FIGS. 7A and 7B show exemplary dynamic fixation images 705 and 710 output from the display 426, respectively. Both dynamic fixation images 705 and 710 include an iBox reference 715 and an eye position reference 720. The iBox reference 715 is a virtual marker on the display 426 that is positioned on the display 426 based on the selected iBox position and represents the iBox itself. The eye position reference 720 is a virtual marker on the display 426 that represents the patient's pupil, and its placement on the display 426 changes in real time when the user attempts to align their eye with the eyepiece 435. In other words, the placement of the eye position reference 720 tracks the eye position relative to the eyepiece 435 based on the output from the alignment tracking camera system 430 or the image sensor 410 (process block 635). In various embodiments, the alignment tracking camera system 430 may be used for overall eye alignment based on pupil / iris tracking, while the image sensor 410 may be used for fine eye alignment based on retina tracking. The dynamic fixation images 705 and 710 may operate as a kind of game where the patient is said to concentrically align two circular markers by moving their eye relative to the eyepiece assembly 435. The iBox alignment is achieved when the eye position reference 720 is moved within the iBox reference 714, as shown in FIG. 7B (decision block 640). By dynamically moving the eye position reference 720, the fixation target is adjusted and the user is prompted or moved to align as they attempt to concentrically align the reference markers (process block 645). Of course, other alignment / fixation images may be implemented to facilitate the threshold alignment necessary to obtain a satisfactory retinal image.

[0028] When threshold alignment is achieved (decision block 640), the illuminator 405 is configured by the controller 415 to select an appropriate illumination pattern for retinal imaging. The illumination pattern may be selected based on pupil position and pupil size to reduce image artifacts and optimize retinal image quality (process block 650). In one embodiment, a look-up table (LUT) can index the illumination pattern to pupil placement and / or pupil size. In yet other embodiments, the LUT may further index the illumination pattern to a POI and / or eye laterality for further pattern refinement. For example, the illumination pattern may take into account not only the current position of the eye relative to the eyepiece assembly 435, but also the anatomical features associated with a given lesion, and thus select an illumination pattern that shifts various image artifacts from that anatomical feature within the retinal image. This may be considered a more fine-grained illumination pattern refinement in addition to the selection of the illumination pattern based on real-time eye placement tracking.

[0029] When threshold alignment is achieved (decision block 640) and an appropriate illumination pattern is selected (process block 650), the illuminator 405 illuminates the retina 475 through the pupil. This illumination may be a white light flash, although the specific wavelength used for illumination (e.g., broadband white light, IR light, near IR, etc.) may be adjusted for a particular lesion or application. The illumination flash in process block 655 may last for a period (e.g., 200 milliseconds) that is below the human physiological response time (e.g., pupil contraction or blink). While the illumination is active, one or more retinal images are acquired (process block 660). In one embodiment, the acquisition of a burst of retinal images (e.g., 5, 10, 20, 50, 100 images) is triggered while the eye remains within the selected eye box as determined from real-time feedback from the alignment tracking camera system 430 (or image sensor 410) between illumination windows.

[0030] The burst of retinal images may be buffered on a camera chip including an image sensor 410, and an Image Signal Processor (ISP) can quickly analyze the quality of the acquired retinal images. The ISP can be regarded as a component of a controller 415 (e.g., a distributed offload computing engine) arranged near the image sensor 410 to enable high-speed image processing. If the image is blocked, unclear, or inappropriate, process 600 returns to process block 630 and repeats the relevant part of process 600. However, if the acquired images are collectively considered sufficient to appropriately capture the region of interest related to the POI, the retinal images can be combined (process block 670) to generate, output, and store a high-quality composite image (process block 675). Various different combining techniques, such as image stacking or others, can be implemented.

[0031] The processes described above are described with respect to computer software and hardware. The techniques described can constitute machine-executable instructions embodied in a tangible or non-transitory machine (e.g., a computer) readable storage medium that, when executed by a machine, cause the machine to perform the operations described. Further, the processes can be embodied in an application specific integrated circuit (ASIC) or other hardware.

[0032] A tangible machine-readable storage medium includes any mechanism that provides (i.e., stores) information in a non-transitory form accessible by a machine (e.g., a computer, a network device, a personal information terminal, a manufacturing tool, any device having a set of one or more processors, etc.). For example, a machine-readable storage medium includes recordable / non-recordable media (e.g., read only memory (ROM), random access memory (RAM), magnetic disk storage media, optical storage media, flash memory devices, etc.).

[0033] The foregoing description of the exemplary embodiments of the invention, including what is described in the abstract, is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Specific embodiments and examples of the invention are described herein for illustrative purposes, but various modifications can be made within the scope of the invention as will be recognized by those of ordinary skill in the art.

[0034] These changes can be made to the invention in light of the above detailed description. In general, the terms used in the following claims should not be construed as limiting the invention to the specific embodiments disclosed herein. Rather, the scope of the invention should be determined completely by the following claims, which are to be construed in accordance with established principles of claim interpretation.

Claims

**Claim 1** A retinal imaging system comprising: an eyepiece lens assembly; an image sensor adapted to acquire a retinal image of an eye through the eyepiece lens assembly; a controller communicatively coupled to the image sensor, the controller including logic that, when executed, causes the retinal imaging system to perform operations, the operations including: acquiring an indicator of a pathologically relevant lesion (POI) associated with the eye; selecting an eye box position for an eye box of the retinal imaging system based at least in part on the POI, the eye box position selection including selecting an eye box position corresponding to a boundary region within a defined space relative to the eyepiece lens assembly; acquiring the retinal image of the eye when the eye is determined to be positioned within the eye box. A retinal imaging system as described above. **Claim 2** The controller further includes additional logic that, when executed, causes the retinal imaging system to perform additional operations, the additional operations including: determining whether the laterality of the eye is a right eye or a left eye; selecting the eye box position based at least in part on both the POI and the laterality of the eye. The retinal imaging system according to claim 1. **Claim 3** The retinal imaging system according to claim 2, wherein the eye box position is different for the right eye and the left eye. **Claim 4** The retinal imaging system according to claim 2, wherein the laterality of the eye is determined based at least in part on a manual user input. **Claim 5** The retinal imaging system according to claim 2, wherein the laterality of the eye is automatically determined by the retinal imaging system based at least in part on a preliminary image of the eye. **Claim 6** The system further includes an illuminator coupled to the controller and positioned to illuminate the eye, the controller further including additional logic that, when executed, causes the retinal imaging system to perform additional operations, the additional operations including: adjusting an illumination pattern output from the illuminator based at least in part on the POI or the laterality of the eye. The retinal imaging system according to claim 2. **Claim 7** The retinal imaging system according to claim 6, wherein the illuminator includes a dynamic ring illuminator surrounding an optical path extending between the eyepiece lens assembly and the image sensor for illuminating the retina of the eye through the eyepiece lens assembly.

8. The retinal imaging system according to claim 1, wherein the eye box position associated with the POI indicated as diabetic retinopathy is different from the eye box position associated with the POI indicated as glaucoma.

9. The system further includes a dynamic fixation target optically coupled to the eyepiece lens assembly such that the dynamic fixation target can be viewed through the eyepiece lens assembly, the dynamic fixation target being electrically coupled to the controller, and the controller including further logic that, when executed, causes the retinal imaging system to perform additional operations, the additional operations including adjusting a fixation position of the dynamic fixation target based at least in part on the POI or the eye box position selected for the POI, the retinal imaging system according to claim 1.

10. The dynamic fixation target includes a dynamic fixation image output from a display, the dynamic fixation image including an eye box reference rendered in a first arrangement on the display selected based at least in part on the POI and the eye box position, and an eye position reference rendered in a second arrangement on the display based at least in part on tracking a real-time position of the eye, the retinal imaging system according to claim 9.

11. The system further includes an alignment tracking camera system coupled to the controller for tracking a real-time arrangement of the pupil or iris of the eye, and the controller includes further logic that, when executed, causes the retinal imaging system to perform additional operations, the additional operations including triggering acquisition of a burst of retinal images including the retinal image using the image sensor when it is determined that the real-time arrangement of the pupil or iris is within the eye box based on feedback from the alignment tracking camera system, the retinal imaging system according to claim 1.

12. A method of imaging the retina of an eye using a retinal imaging system, the method comprising: determining whether the laterality of the eye is either the right eye or the left eye; Selecting an eye box position for an eye box of the retinal imaging system based at least in part on the laterality, wherein the eye box corresponds to a boundary region within a space defined relative to the eyepiece assembly, and selecting the eye box position; Obtaining a retinal image of the eye when the eye is determined to be positioned within the eye box. A method comprising: **Claim 13** Obtaining an index of a pathological lesion (POI) associated with the eye; The method according to claim 12, further comprising selecting the eye box position based at least in part on both the POI and the laterality of the eye. **Claim 14** The method according to claim 13, further comprising adjusting an illumination pattern for illuminating the eye based at least in part on the laterality of the eye and the POI. **Claim 15** The method according to claim 14, wherein the illuminator includes a dynamic ring illuminator surrounding an optical path extending between the eyepiece assembly and the image sensor for illuminating the retina of the eye through the eyepiece assembly. **Claim 16** The method according to claim 13, further comprising adjusting a fixed position of a dynamic fixed image viewable through the eyepiece assembly based on at least one of the POI or the laterality of the eye. **Claim 17** Adjusting the fixed position of the dynamic fixed image comprises: Displaying an eye box reference for a first arrangement within the dynamic fixed image, the first arrangement being selected based on at least one of the POI or the laterality of the eye; Displaying an eye position reference for a second arrangement within the dynamic fixed image, the second arrangement being determined based at least in part on tracking the real-time position of the eye. The method according to claim 16. **Claim 18** The method according to claim 12, wherein the laterality of the eye is determined based at least in part on a manual user input. **Claim 19** The method according to claim 12, wherein the laterality of the eye is automatically determined by the retinal imaging system based at least in part on a preliminary image of the eye. **Claim 20** Tracking the real-time arrangement of the pupil or iris of the eye using an alignment tracking camera system separate from the image sensor. The method according to claim 12, further comprising triggering, using the image sensor, acquisition of a burst of retinal images including the retinal image when it is determined that the real-time placement of the pupil or the iris is within the eye box based on feedback from the alignment tracking camera system.

Images