Retinal imaging system and retinal imaging adapter and related methods of use

Abstract

The present invention provides a retinal imaging system suitable for selectively imaging a first eye and a second eye of a user. A retinal imaging system and retinal imaging adapter, and related methods of use, are described. In an embodiment, the retinal imaging system includes a monocular image sensor adapted to acquire retinal images of an eye, and a binocular eyepiece configured to slide relative to the monocular image sensor and shaped to couple to a user's face. In an embodiment, the monocular image sensor is positioned to acquire a first retinal image of a first eye of the user at a first position of the binocular eyepiece and to acquire a second retinal image of a second eye of the user at a second position of the binocular eyepiece. In an embodiment, the retinal imaging system includes a sliding bracket coupled to a housing of the retinal imaging system and slidably coupled to the binocular eyepiece.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of U.S. Provisional Patent Application No. 63 / 370,406, filed August 4, 2022, which is incorporated herein by reference in its entirety.

[0002] FIELD OF THE INVENTION FIELD OF THE DISCLOSURE The present disclosure relates generally to retinal imaging techniques, and particularly, but not exclusively, to illumination techniques for retinal imaging. [Background technology]

[0003] Retinal imaging is part of the basic eye examination for screening, on-site diagnosis, and progression monitoring of many retinal diseases. High-fidelity retinal images are important for accurate screening, diagnosis, and monitoring.

[0004] Conventional retinal camera systems use a single eyebox with a single position, typically defined relative to the eyepiece of the conventional retinal 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 each individual eye, and further does not take into account the need to obtain higher quality images of specific regions of interest within the left and / or right eye to help physicians screen, diagnose, monitor, or treat specific ocular conditions.

[0005] One challenge in using such conventional retinal imaging systems is that the user must know which eye is being imaged. Often, one eye is imaged twice, or the wrong eye is imaged. Such scenarios can require additional imaging and may involve a patient re-examination. Complexity and confusion can increase when the operator is sitting opposite the patient, and therefore it is not clear which eye should be imaged and which direction the subject should move to align the subject's eye with the retinal imaging system. [Brief explanation of the drawings]

[0006] Non-limiting and non-exhaustive embodiments of the present invention are described with reference to the following figures, in which like reference numerals refer to like parts throughout the various views unless otherwise specified. Not every instance of an element is necessarily labeled, so as to avoid cluttering the figures where appropriate. The figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles described. [Figure 1A] 1 shows a perspective view of a retinal imaging system according to an embodiment of the present disclosure. [Figure 1B] 1B illustrates a front view of the retinal imaging system of FIG. 1A in a first position according to an embodiment of the present disclosure. [Figure 1C] 1B shows a front view of the retinal imaging system of FIG. 1A in a second position according to an embodiment of the present disclosure. [Figure 1D] 1B shows a top view of the retinal imaging system of FIG. 1A according to an embodiment of the present disclosure. [Figure 1E] 1B shows a side view of the retinal imaging system of FIG. 1A according to an embodiment of the present disclosure. [Figure 2A] 1 shows a perspective view of a retinal imaging adapter according to an embodiment of the present disclosure. [Figure 2B] 2B illustrates a top view of the retinal imaging adapter of FIG. 2A in a first position according to an embodiment of the present disclosure. [Figure 2C] 2B illustrates another top view of the retinal imaging adapter of FIG. 2A in a second position according to an embodiment of the present disclosure. [Figure 2D] 2B shows a bottom view of the retinal imaging adapter of FIG. 2A in accordance with an embodiment of the present disclosure. [Figure 2E] 2B shows another perspective view of the retinal imaging adapter of FIG. 2A in accordance with an embodiment of the present disclosure. [Figure 2F] 2B shows a front view of the retinal imaging adapter of FIG. 2A in accordance with an embodiment of the present disclosure. [Figure 3] FIG. 1 is a partial exploded view of a retinal imaging adapter according to an embodiment of the present disclosure. [Figure 4]1 illustrates a schematic diagram of a retinal imaging system according to an embodiment of the present disclosure. [Figure 5] FIG. 1 is a perspective view of a retinal imaging system according to an embodiment of the present disclosure. [Figure 6-1] 1 is a flowchart illustrating a process for capturing retinal images based on eye laterality according to an embodiment of the present disclosure. [Figure 6-2] 1 is a flowchart illustrating a process for capturing retinal images based on eye laterality according to an embodiment of the present disclosure. [Figure 7A] 1 illustrates a dynamic fixation target including eyebox references and eye position references that move the eyes into a specific eyebox and alignment, according to an embodiment of the present disclosure. [Figure 7B] 1 illustrates a dynamic fixation target including eyebox references and eye position references that move the eyes into a specific eyebox and alignment, according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0007] Embodiments of a retinal imaging system, a retinal imaging adapter, and a method of operating a retinal imaging system are described herein. In the following description, numerous specific details are set forth to provide a thorough understanding of the embodiments. However, those skilled in the art will recognize that the techniques described herein can 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 or described in detail to avoid obscuring certain aspects.

[0008] References throughout this specification to "one embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrase "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 screening, diagnosing, and monitoring many retinal diseases. To this end, it is desirable to acquire high-fidelity images of both eyes of a user with two eyes. Conventional retinal imaging systems may not clearly indicate which eye is being imaged when acquiring a user's retinal image.

[0010] To address these and related needs, the present disclosure provides, in one aspect, a retinal imaging system suitable for selectively imaging a first eye and a second eye of a user. In this regard, attention is directed to Figures 1A-1E, which show a retinal imaging system 100 according to an embodiment of the present disclosure.

[0011] Figure 1A shows a perspective view of retinal imaging system 100. Figure 1B shows a front view of retinal imaging system 100. Figure 1C shows another front view of retinal imaging system 100. Figure 1D shows a top view of retinal imaging system 100. Figure 1E shows a side view of retinal imaging system 100.

[0012] In the illustrated embodiment, retinal imaging system 100 is shown to include a housing 102 and a monocular image sensor 104 disposed within housing 102 and adapted to acquire retinal images of a user's eye. In an embodiment, monocular image sensor 104 is configured to acquire retinal images of one eye per retinal image. Further discussion of examples of retinal image sensors and their component parts and operation according to embodiments of the present disclosure is provided further herein with respect to FIG. 4. In an embodiment, monocular image sensor 104 includes a lens, an illuminator, an image sensor, etc., as further described herein with respect to FIG. 4.

[0013] As shown, retinal imaging system 100 further includes binocular eyepieces 106. As discussed further herein, binocular eyepieces 106 are configured to slide relative to housing 102, such as relative to monocular image sensor 104, and are shaped to couple to a user's face. In this regard, monocular image sensor 104 is positioned to capture a first retinal image of a first eye of a user at a first position of binocular eyepieces 106. See, e.g., FIG. 1B. Similarly, monocular image sensor 104 is positioned to capture a second retinal image of a second eye of a user at a second position of binocular eyepieces 106. See, e.g., FIG. 1C.

[0014] The binocular eyepieces 106 are shown as goggles shaped to mate with and fit the user's face, and while a goggle-like shape is shown, it will be understood that other form factors are possible that allow for the acquisition of retinal images of both of the patient's eyes.

[0015] In the illustrated embodiment, retinal imaging system 100 is shown to include a sliding bracket 116 coupled to housing 102, which is also slidably coupled to binocular eyepieces 106. The slidable coupling between sliding bracket 116 and binocular eyepieces allows binocular eyepieces 106 to slide between first and second positions relative to the monocular imaging sensor to capture retinal images of a user's first and second eyes, respectively.

[0016] The sliding bracket 116 defines a bracket opening 118, which is shown shaped to allow light from an interior 120 of the binocular eyepiece 106 to pass through the bracket opening 118 for reception by the monocular image sensor 104. As shown, the bracket opening 118 overlaps with the monocular image sensor 104, thereby allowing light to pass through the bracket opening 118 from the interior 120 and be received by the monocular image sensor 104.

[0017] In an embodiment, a central axis 122 of the bracket opening 118 is collinear with an imaging axis 124 of the monocular image sensor 104. In an embodiment, the binocular eyepiece 106 is configured to slide orthogonally relative to the imaging axis 124. In an embodiment, such orthogonal sliding relative to the imaging axis 124 allows the binocular eyepiece 106 to move from a first position to a second position and vice versa, such as to capture retinal images of a user's first and second eyes using the monocular image sensor 104.

[0018] In an embodiment, the binocular eyepiece 106 is configured to move relative to the monocular image sensor 104 in a direction approximately perpendicular to the median plane of the user's face, i.e., approximately parallel to the coronal plane, when the face is positioned relative to the binocular eyepiece 106.

[0019] In an embodiment, the sliding bracket 116 includes indicia in the form of markings, etchings, indentations, etc. that indicate where the sliding bracket 116 should be positioned relative to the binocular eyepiece 106 markers to achieve different positions of the retinal imaging system 100. In the illustrated embodiment, the binocular eyepiece 106 is shown with an eyepiece reference marker 126, shown here as a chevron. Also shown, the sliding bracket 116 includes a first bracket reference marker 128 (shown here as a single dot) that aligns with the eyepiece reference marker 126 when the binocular eyepiece 106 is in a first position, and a second bracket reference marker 130 (shown here as a perpendicular pair of dots) that aligns with the eyepiece reference marker 126 when the binocular eyepiece 106 is in a second position. While chevrons and dots are shown as markers, it will be understood that other written, printed, embossed, etc. indicia are within the scope of the present disclosure. Alignment of the reference marker on the binocular eyepiece 106 with the first bracket reference marker 128 indicates that the binocular eyepiece 106 is in a first position, and alignment with the second bracket reference marker 130 indicates that the binocular eyepiece 106 is in a second position.

[0020] The retinal imaging system 100 may include additional structures and features that indicate the alignment of the binocular eyepieces 106 relative to the monocular image sensor 104 according to various positions of the retinal imaging system 100. In an embodiment, the edge curvature 146 of the binocular eyepieces 106 matches the edge curvature 148 of the sliding bracket 116. Such curvature matching is configured to provide a visual cue to a user and / or operator, etc. of the retinal imaging system 100, that the binocular eyepieces 106 are positioned in one of the first position or the second position when the edge curvature 146 of the binocular eyepieces 106 and the edge curvature 148 of the sliding bracket 116 are aligned. In another embodiment, the binocular eyepieces 106 and / or the sliding bracket 116 include one or more detents, such as one or more spring ball detents, configured to provide an audible and / or tactile indication to a user that the binocular eyepieces 106 are in one of the first position or the second position.

[0021] In an embodiment, the binocular eyepieces 106 are configured to move relative to the monocular image sensor 104 to position the user's eyes closer to or farther from the monocular image sensor 104. Such relative movement may be useful to adjust the placement of the user's eyes within the eyebox of the monocular image sensor 104 to obtain a proper retinal image of the eyes. In an embodiment, the sliding bracket 116 is configured to move along an imaging axis 124 of the monocular image sensor 104 relative to the housing 102.

[0022] As shown, the retinal imaging system 100 includes at least two divider bars 132 coupled to the sliding bracket 116. In an embodiment, the at least two divider bars 132 are slidably received by the housing 102 and configured to move the sliding bracket 116 relative to the housing 102, such as along the imaging axis 124. In an embodiment, the at least two divider bars 132 are received by the housing 102 with respective linear bearings. By including the at least two divider bars 132, rotational movement of the binocular eyepieces 106, such as about the imaging axis 124, is limited or eliminated.

[0023] In an embodiment, the at least two divider bars 132 are spring-biased, such as a constant force spring, to provide resistance to moving the binocular eyepieces 106 toward the monocular image sensor 104. In an embodiment, the biasing force of the spring is sufficient to return the binocular eyepieces 106 to a rest or starting position after compression, but not so high that they cannot be compressed by the user's face, such as the user's neck muscles. In this regard, a user can adjust the binocular eyepieces 106 relative to the monocular image sensor 104 (i.e., position their eyes within the eyeboxes of the monocular image sensor 104), and the binocular eyepieces 106 will then return to their original position.

[0024] As described further herein, in certain embodiments, the binocular eyepieces 106 are configured to conform to a user's face, such as when portions of the face are pressed or otherwise positioned against the binocular eyepieces 106. In embodiments, the binocular eyepieces 106 include a frame 134 slidably coupled to the sliding bracket 116 and a compressible edge cushion 136 disposed on an eye-facing edge 138 of the frame 134 and positioned to contact the user's face. The compressible edge cushion 136 is configured to provide comfort to the user. The compressible edge cushion 136 also allows the user to move their face, and particularly their eyes, relative to the binocular eyepieces 106 while maintaining contact with the binocular eyepieces 106, and in this regard, allows for limiting light leakage from between the binocular eyepieces 106 and the user's face into the interior 120 of the binocular eyepieces 106.

[0025] In the illustrated embodiment, the binocular eyepieces 106 include a forehead rest 150 that is shaped and positioned to contact the user's forehead when the user's face is positioned against the binocular eyepieces. As shown, the binocular eyepieces 106 also include a cheek rest 152 that is shaped and positioned to contact the user's cheek when the user's face is positioned against the binocular eyepieces 106. In an embodiment, the forehead rest 150 and cheek rest 152 are shaped and positioned to induce a downward pitch of the user's head when the user's forehead and cheek are positioned against the binocular eyepieces 106. In this regard, the binocular eyepieces 106, including the forehead rest 150 and cheek rest 152, are configured to induce an opening of the palpebral fissure height (visible portion of the eye), which facilitates eye tracking by minimizing eyelid interference.

[0026] In an embodiment, the binocular eyepieces 106 are shaped to provide space for the user's nose, such as when the face is positioned against the binocular eyepieces 106 and when the user is adjusting their eyes relative to the monocular image sensor 104 to achieve alignment between the eyes and the monocular image sensor 104. In this regard, the binocular eyepieces 106 define a cutout 154 that is shaped to receive the user's nose and allow movement of the nose within the cutout 154 when the user's face is positioned against the binocular eyepieces 106.

[0027] In embodiments, the binocular eyepieces 106 are shaped or otherwise configured to limit light entering the interior 120 of the binocular eyepieces 106 and the user's face when the user's face is placed against the compressible edge cushion 136. In this regard, in embodiments, the frame 134 is opaque to visible and other light, such as to limit light leakage into the interior 120. In embodiments, the frame 134 has a matte finish and / or a dark color configured to reduce light reflections and absorb stray light, respectively, that may degrade retinal image quality.

[0028] As shown, frame 134 defines a frame opening 140 that is shaped and positioned to overlap bracket opening 118 when sliding bracket 116 is coupled to binocular eyepiece 106 in both the first and second positions. In this regard, frame 134 is configured to provide a line of sight between monocular image sensor 104 and a user's first and second eyes.

[0029] In embodiments, the retinal imaging system 100 is configured to adjust the angle of the binocular eyepieces 106 relative to the user's face. In particular, in embodiments, the retinal imaging system 100 is configured to adjust the angle of the binocular eyepieces 106 relative to the user's canthus, such as when the user's face is positioned relative to the binocular eyepieces 106. In this regard, the retinal imaging system 100 is configured to align the user's eyes with the optical path of the monocular image sensor 104 without, for example, adjusting the height of the retinal imaging system 100. Thus, as shown, the housing 102 comprises a first portion 156 that carries the monocular image sensor 104 and a second portion 158 rotatably coupled to the first portion 156. In the illustrated embodiment, the second portion 158 is configured to be placed on a mounting surface such as a tabletop or desk. While a desktop retinal imaging system 100 is illustrated, it will be understood that the retinal imaging system 100 may be configured to rest on the floor, hang from a ceiling, or move up and down a separate structure. By rotating the first portion 156 relative to the second portion 158, the monocular image sensor 104 can be selectively aligned with the user's canthus and / or the user's eye can be aligned with the monocular image sensor 104.

[0030] In another aspect, the present disclosure provides a retinal imaging adapter. In an embodiment, the retinal imaging adapter is shaped or otherwise configured to couple with a retinal imaging system for obtaining retinal images of a user's eye. In an embodiment, the retinal imaging adapter is an example of a portion of a retinal imaging system 100, further described herein with respect to FIGS. 1A-1E.

[0031] In an embodiment, the retinal imaging adapter comprises a binocular eyepiece shaped to couple to a user's face, and a sliding bracket configured to couple to a retinal imaging system and slidably coupled to the binocular eyepiece, the sliding bracket defining a bracket opening, the bracket opening shaped to allow light from inside the binocular eyepiece to pass through the bracket opening.

[0032] In this regard, attention is directed to Figures 2A-2F, which illustrate a retinal imaging adapter 201 in accordance with an embodiment of the present disclosure. Figure 2A illustrates a perspective view of the retinal imaging adapter 201. Figure 2B illustrates a top view of the retinal imaging adapter 201. Figure 2C illustrates another top view of the retinal imaging adapter 201. Figure 2D illustrates a bottom view of the retinal imaging adapter 201. Figure 2E illustrates another perspective view of the retinal imaging adapter 201. Figure 2F illustrates a front view of the retinal imaging adapter 201.

[0033] As shown, retinal imaging adapter 201 includes binocular eyepieces 206 shaped to couple to a user's face. In an embodiment, binocular eyepieces 206 are an example of binocular eyepieces 106, which are further described herein with respect to Figures 1A-1E.

[0034] In the illustrated embodiment, the retinal imaging adapter 201 further includes a sliding bracket 216 configured to couple, such as fixedly couple, to a retinal imaging system and to be slidably coupled to the binocular eyepieces 206. As shown, the sliding bracket 216 defines a bracket opening 218 that is shaped to allow light from an interior 220 of the binocular eyepieces 206 to pass through the bracket opening 218. In the illustrated embodiment, a central axis 222 of the bracket opening is positioned to be aligned with an imaging axis (not shown, see FIGS. 1A-1E ) of a retinal imaging system coupled to the retinal imaging adapter 201.

[0035] In this regard, the bracket opening 218 is shaped and positioned to allow light from within the interior 220 of the binocular eyepiece 206, such as light emitted from within the user's eye, to pass through the bracket opening 218 and, for example, onto a monocular image sensor of a retinal imaging system coupled to the retinal imaging adapter 201.

[0036] As shown, the binocular eyepieces 206 are configured to slide relative to the sliding bracket 216. In this regard, when the binocular eyepieces 206 slide relative to the sliding bracket 216 coupled thereto, the bracket opening 218 is positioned to allow light from a first eye of a user to pass through the bracket opening 218 in a first position of the binocular eyepieces 206 and to allow light from a second eye of the user to pass through the bracket opening 218 in a second position of the binocular eyepieces 206.

[0037] In the illustrated embodiment, the binocular eyepiece 206 includes a frame 234 slidably coupled to the sliding bracket 216. In an embodiment, the frame 234 is configured to limit light from the external environment entering the interior 220 of the frame 234, such as to improve retinal image quality. In an embodiment, the frame 234 is opaque to light, such as visible light, infrared light, or ultraviolet light. In an embodiment, the frame 234 has a matte finish configured to limit light reflection. In an embodiment, the frame 234 has a dark color, such as black, configured to absorb a broad spectrum of light incident on the frame 234.

[0038] The binocular eyepieces 206 are also shown to include compressible edge cushions 236 disposed on the eye-facing edges 238 of the frame 234 and positioned to contact the user's face. In embodiments, the compressible edge cushions 236 are configured to compress and / or conform to the user's face when placed against the compressible edge cushions 236. In this regard, the binocular eyepieces 206 are shaped to limit light entering the interior 220 of the binocular eyepieces 206 and the user's face when the user's face is placed against the compressible edge cushions 236.

[0039] As shown, the binocular eyepiece 206 also comprises or otherwise defines a forehead rest 250 that is shaped and positioned to contact the user's forehead when the user's face is placed against the binocular eyepiece, and a cheek rest 252 that is shaped and positioned to contact the user's cheek when the user's face is placed against the binocular eyepiece 206. In this regard, the binocular eyepiece 206 is shaped to receive a user's face that is placed against the binocular eyepiece 206, such as to obtain retinal imaging.

[0040] In the illustrated embodiment, the binocular eyepieces 206, and in particular the frame 234 and compressible edge cushion 236, define a cutout 254 that is shaped to receive and allow movement of the user's nose within the cutout 254 when the user's face is positioned against the binocular eyepieces 206. As described further herein with respect to Figures 1A-1E, the cutout 254 allows the user to rotate or otherwise adjust their head to align their eyes with the imaging optics of the monocular image sensor of the retinal imaging system.

[0041] In an embodiment, frame 234 defines a frame opening 240 that is shaped to overlap bracket opening 218 when sliding bracket 216 is coupled to binocular eyepiece 206 in both the first and second positions. In this regard, frame opening 240 is shaped to allow light from interior 220 of binocular eyepiece 206 to pass through bracket opening 218 and exit interior 220, such as for reception by a monocular image sensor of a retinal imaging system coupled to retinal imaging adapter 201.

[0042] As shown, the binocular eyepieces 206 include an eyepiece reference marker 226. The sliding bracket 216 is shown to include a first bracket reference marker 228 that aligns with the eyepiece reference marker 226 when the binocular eyepieces 206 are in a first position, and a second bracket reference marker 230 that aligns with the eyepiece reference marker 226 when the binocular eyepieces 206 are in a second position. As described further herein with respect to FIGS. 1A-1E , the eyepiece reference marker 226 and the first and second bracket reference markers 228, 230 are configured to assist a user in aligning the binocular eyepieces 206 with the sliding bracket 216 to first and second positions, respectively, such as to obtain retinal images of the user's first and second eyes.

[0043] As noted above, the retinal imaging adapter 201 is shaped or otherwise configured to couple to a retinal imaging system, such as a housing for the retinal imaging system. In this regard, in an embodiment, the retinal imaging adapter 201 includes a mounting attachment 242 disposed within a sliding bracket 216 that is configured to be releasably attached to a housing for the retinal imaging system.

[0044] 3 is a partial exploded view of a retinal imaging adapter 301 according to an embodiment of the present disclosure. In an embodiment, the portion of the retinal imaging adapter 301 is part of the retinal imaging adapter 201, which is further described herein with respect to Figures 2A-2E. In an embodiment, the portion of the retinal imaging adapter 301 is part of the binocular eyepiece 106, which is further described herein with respect to Figures 1A-1E.

[0045] The illustrated embodiment shows a binocular eyepiece 306. As shown, the binocular eyepiece 306 comprises a frame 334 and a compressible edge cushion 336 disposed on an eye-facing edge 338 of the frame 334 and positioned to contact a user's face. In an embodiment, the compressible edge cushion 336 comprises a soft, compressible material configured to conform to a user's face disposed against the compressible edge cushion 336.

[0046] Binocular eyepiece 306 is shown to further include a molding 344 that is shaped to couple to frame 334 on a first side and to compressible edge cushion 336 on a second side.

[0047] The illustrated binocular eyepiece 306 is configured to be slidably coupled to a sliding bracket, such as sliding bracket 116 and / or 216 discussed further herein with respect to Figures 1A-1E and 2A-2E.

[0048] As shown, the binocular eyepiece comprises and / or defines a forehead rest 350 that is shaped and positioned to contact the user's forehead when the user's face is placed against the binocular eyepiece, and a cheek rest 352 that is shaped and positioned to contact the user's cheek when the user's face is placed against the binocular eyepiece.

[0049] The binocular eyepieces also define a notch 354 which is shown shaped to receive the user's nose and allow movement of the nose within the notch 354 when the user's face is positioned against the binocular eyepieces.

[0050] 4 illustrates a retinal imaging system 400 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 and 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 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 fixation image 427, which may include one or more fiducial markers 428 representing the relative position of the eyebox and / or eye.

[0051] The optical relay system functions to direct (e.g., pass through or reflect) illumination light 480 output from illuminator 405 along an illumination path through the pupil of eye 470 to illuminate retina 475, while directing image light 485 of retina 475 (i.e., a retinal image) along an imaging path to image sensor 410. Image light 485 is formed by scattered reflection of illumination light 480 from 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 image sensor 410, while optically coupling dynamic fixation target 425 to eyepiece assembly 435 and directing a dynamic fixation image 427 output from display 426 to eye 470. Beam splitter 450 may be implemented as a polarizing beam splitter, a non-polarizing beam splitter (e.g., 90% transmission and 10% reflection, a 50 / 50 beam splitter, etc.), a multi-layer dichroic beam splitter, or others. The optical relay system includes several lenses, such as lenses 435, 440, and 445, to focus various light paths as needed. For example, lens 435 may include one or more lens elements that collectively form an eyepiece assembly that is displaced from the cornea of eye 470 by eye relief 495 during operation. Lens 440 may include one or more lens elements for focusing image light 485 onto image sensor 410. Lens 445 may include one or more lens elements for focusing dynamic fixation image 427. It should be understood that the optical relay system can be implemented using numerous and diverse optical elements (e.g., lenses, reflective surfaces, diffractive surfaces, etc.) and may differ from the configuration shown in FIG. 4 .

[0052] In one embodiment, a dynamic fixation image 427 output from the display 426 represents a fixation point around which the patient can adjust their focus and fixate their gaze. 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. 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 as an actuated or optically manipulated physical target(s). The dynamic fixation target 425 can not only help achieve alignment between the retinal imaging system 400 and the eye 470 by providing the patient with visual feedback, but can also provide the patient with a fixation point / target around which the patient can adjust and stabilize their vision. The dynamic fixation target can be moved by translating the image of the fixation target (e.g., fiducial 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 may be implemented with a variety of technologies, including a liquid crystal display (LCD), a light emitting diode (LED), various illuminated shapes (e.g., an 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 could be a physical object (e.g., a crosshair) that is physically manipulated.

[0053] The controller 415 is coupled to the image sensor 410, the display 426, the illuminator 405, and the alignment and tracking camera system 430 to coordinate their operation. The controller 415 may include software / firmware logic executing on a microcontroller, hardware logic (e.g., an application-specific integrated circuit, a field-programmable gate array, etc.), or a combination of software and hardware logic. While FIG. 4 depicts the controller 415 as distinct functional elements, the logical functions performed by the controller 415 may be distributed across several hardware elements. The controller 415 may further include input / output (I / O) ports, a communication system, or others. The controller 415 is coupled to a user interface 420 to receive user input and provide user control for the retinal imaging system 400. The user interface 420 may include one or more buttons, dials, joysticks, feedback displays, indicator lights, etc.

[0054] The image sensor 410 may 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 associated 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 retinal images buffered in the on-board 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 composite retinal images. The integrated ISP may be considered a decentralized component of the controller 415.

[0055] The alignment and 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 assembly 435 and the eye 470. The system 430 can operate using a variety of different techniques to track the relative position 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 assembly 435 to enable triangulation and obtain X, Y, and Z global position information for 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 retinal images are acquired using bursts of visible spectrum light output from the illuminator 405 through the eyepiece assembly 435. In such embodiments, an IR filter may be positioned in the image path to filter the IR tracking light. In some embodiments, the tracking illumination is temporarily offset from the image acquisition with the white light bursts.

[0056] Lateral eye alignment may be measured by system 430 via retinal images acquired by image sensor 410, or separately / additionally. In the illustrated embodiment, system 430 is positioned externally to view eye 470 from outside eyepiece assembly 435. In other embodiments, system 430 may be optically coupled using optical relay components to view and track eye 470 through eyepiece assembly 435.

[0057] During operation, the controller 415 operates the illuminator 405 and the retinal image sensor 410 to capture one or more retinal images. Illumination light 480 is directed through the pupil of the eye 470 to illuminate the retina 475. Scattered reflections from the retina 475 are directed back to the image sensor 410 through the aperture 455 along an image path. When the eye 470 is properly aligned within a selected eyebox of the system 400, the aperture 455 operates to block harmful reflections and light scattering that would adversely affect the retinal image while allowing the image light itself to pass. Prior to capturing a retinal image, the controller 415 operates the display 426 to output a dynamic fixation image 427 for guiding the patient's gaze. 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 assembly 435. These initial alignment images may be illuminated with infrared (IR) light output from illuminator 405 (or a separate illuminator associated with alignment and tracking camera system 430) to avoid triggering an iris contraction response that would narrow the imaging path to 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 controller 415 to identify any misalignments, reposition eye position fiducials in dynamic fixation image 427 to encourage proper eye positioning relative to the selected eyebox, and then trigger the acquisition of one or more subsequent eye images (e.g., retinal image bursts) by image sensor 410. The subsequent images may be full color images, specific color images, or IR images, as desired.

[0058] 5 is a perspective view of a retinal imaging system 500, in accordance with an embodiment of the present disclosure. As shown, retinal imaging system 500 is shown to include a monocular image sensor 504 disposed within a housing 502 and a binocular eyepiece 516 slidably coupled to housing 502. In an embodiment, monocular image sensor 504, housing 502, and binocular eyepiece 516 are examples of monocular image sensor 104, housing 102, and binocular eyepiece 116, which are further described herein with respect to FIGS. 1A-1E.

[0059] The retinal imaging system 500 is further shown to include a focus knob 560 configured to selectively focus an image viewable by the user's eye when the user's face is positioned relative to the binocular eyepiece 516, such as during retinal imaging of the eye.

[0060] In the illustrated embodiment, the retinal imaging system 500 includes a user interface 562, shown here as a laptop computer. While a laptop computer is shown, it will be understood that other user interfaces 562, such as tablets, smartphones, touchscreens, etc., are within the scope of the present disclosure. In an embodiment, the user interface 562 is an example of the user interface 420 described further herein with respect to FIG. 4. In an embodiment, the user interface 562 is configured to receive user input and provide user control over the retinal imaging system 562.

[0061] 6 is a flowchart illustrating a process 600 for capturing a retinal image based on eye laterality, 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, one of ordinary skill in the art having the benefit of this disclosure will understand that some of the process blocks may be performed in various orders not illustrated, or even in parallel.

[0062] At process block 605, the retinal imaging process is initiated. Initiation may include a user pressing a power button on user interface 420. After powering up, retinal imaging system 400 may, as part of process block 610, request the positioning of a binocular eyepiece, such as binocular eyepiece 516, to acquire a retinal image of a first eye.

[0063] At process block 615, the user interface 420 may request confirmation of placement of the binocular eyepiece 516 in the first position. Requesting such confirmation from the user and / or operator has been found to increase the likelihood that the binocular eyepiece 516 will be placed in the correct position, such as to acquire a retinal image of the first eye.

[0064] At process block 620, illumination is enabled to obtain a preliminary eye image to facilitate eye tracking and / or determine eye laterality. In one embodiment, this initial illumination is IR illumination output from the alignment and tracking camera system 430.

[0065] At process block 625, the laterality of the eye (i.e., right or left eye) is determined. The laterality of the eye may be manually input via user interface 420 or may be automatically determined by 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 image sensor 410 and / or an eye image acquired by alignment and tracking camera system 430.

[0066] If an eye that does not correspond to the first position of the binocular eyepieces appears to be imaged in the preliminary image, as determined at decision block 630, the user interface 420 requests confirmation of placement of the binocular eyepieces in the first position as part of process block 635. Subsequently, the laterality of the eye is again determined at process block 640.

[0067] Following process block 640 or 635, regardless of which eye is in position to be imaged, the user is asked to focus the image as displayed by display 426 using focus knob 560 (process block 645).

[0068] Once the laterality of the eye is determined (process blocks 625-640), an eyebox location for the retinal imaging system 400 may be selected (process block 650). The eyebox location is the location of the eyebox of the retinal imaging system and is a bounded area in space defined for the eyepiece assembly. The eyebox location for the right eye is generally offset to the left (e.g., offset about 1.5 mm to the left), while the eyebox location for the left eye is generally offset to the right (e.g., offset about 1.5 mm to the right).

[0069] Once the eyebox position is selected, the fixation position of the dynamic fixation target 425 can be configured to prompt the eye 470 to adjust its position and / or gaze direction accordingly (process block 655). FIGS. 7A and 7B show exemplary dynamic fixation images 705 and 710, respectively, output from the display 426. Both dynamic fixation images 705 and 710 include an eyebox fiducial 715 and an eye position fiducial 720. The eyebox fiducial 715 is positioned on the display 426 based on the selected eyebox position and is a virtual marker on the display 426 that represents the eyebox itself. The eye position fiducial 720 is a virtual marker on the display 426 that represents the patient's pupil, and its position on the display 426 changes in real time as the user attempts to align their eye with the eyepiece 435. In other words, the position of the eye position fiducial 720 tracks the eye position relative to the eyepiece 435 based on output from the alignment tracking camera system 430 or image sensor 410 (process block 660). In various embodiments, the alignment / tracking camera system 430 may be used for gross 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 in which the patient is asked to concentrically align two circular markers by moving their eyes relative to the eyepiece assembly 435. Eyebox alignment is achieved when the eye position fiducial 720 is moved within the eyebox fiducial 714 (decision block 665), as shown in FIG. 7B. By dynamically moving the eye position fiducial 720, the fixation target is adjusted, and the user is prompted or moved to align as they attempt to concentrically align the fiducial markers (process block 670). Of course, other alignment / fixation images may be implemented to facilitate the threshold alignment required to obtain satisfactory retinal images.

[0070] Once threshold alignment is achieved (decision block 665), 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 670). In one embodiment, a lookup table (LUT) may index the illumination pattern to pupil position and / or pupil size. In yet other embodiments, the LUT may further index the illumination pattern to the POI and / or eye laterality for further pattern refinement. For example, the illumination pattern may consider not only the current position of the eye relative to the eyepiece assembly 435 but also anatomical features associated with a given pathology, thus selecting an illumination pattern that shifts various image artifacts from those anatomical features in the retinal image. This may be considered a finer illumination pattern refinement in addition to selecting an illumination pattern based on real-time eye position tracking.

[0071] Once threshold alignment is achieved (decision block 665) and an appropriate illumination pattern is selected (process block 675), 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 tailored to specific conditions or applications. The illumination flash in process block 680 may last for a duration (e.g., 200 milliseconds) that is equal to or less than a human physiological response time (e.g., pupil constriction or blink). While the illumination is active, one or more retinal images are acquired (process block 685). In one embodiment, the acquisition of a burst of retinal images (e.g., 5, 10, 20, 50, 100 images) is triggered during the illumination window and while the eye remains within the selected eyebox, as determined from real-time feedback from the alignment and tracking camera system 430 (or image sensor 410).

[0072] The burst of retinal images may be buffered on the camera chip containing the image sensor 410, and an image signal processor (ISP) can quickly analyze the quality of the acquired retinal images. The ISP may be considered a component of the controller 415 (e.g., a distributed offload computation engine) located near the image sensor 410 to enable high-speed image processing. If the images are occluded, unclear, or inadequate, the process 600 returns to process block 650 and repeats the relevant portion of the process 600. However, if the acquired images are collectively deemed sufficient to adequately capture an image of the retina, the retinal images may be stored (process block 675) to provide a high-quality retinal image.

[0073] After saving the retinal image of the first imaged eye, the retinal imaging system may begin acquiring retinal images of eyes not previously imaged. In this regard, the retinal imaging system may proceed to process blocks 610-690, but may acquire retinal images of eyes not previously imaged. More specifically, the retinal imaging system may request, using the user interface 426 or the like, placement of the binocular eyepieces in a position for imaging the previously unimaged eyes (process block 692). As described above, method 600 requests placement of the binocular eyepieces in a first position (process block 610). However, in the process of acquiring the first retinal image, method 600 considers that the binocular eyepieces are positioned in a second position and / or that the second eye is being imaged rather than the first eye. In other words, the first retinal image may be a retinal image of the second eye rather than the first eye. In this regard, process block 692 calls for placing the binocular eyepiece in a fixed position to image the previously unimaged eye, which may be either the first or second position of the binocular eyepiece, depending on which eye was previously imaged.

[0074] After requesting that the binocular eyepieces be placed in a fixed position to image a previously unimaged eye, the retinal imaging system may request confirmation of the placement of the binocular eyepieces in the requested position at process block 694 (i.e., to obtain a retinal image of a previously unimaged eye).

[0075] After requesting placement of the binocular eyepieces in a fixed position (process block 692) to image a previously unimaged eye and / or requesting confirmation of placement of the binocular eyepieces in a fixed position at a requested location (process block 694), the retinal imaging system determines the laterality of the eye (i.e., which eye is being imaged) as part of process block 695.

[0076] If, at decision block 696, it is determined that the eye being imaged is a previously imaged eye, the process of requesting and confirming binocular eyepiece placement (process blocks 692 and 694) and determining eye laterality is repeated until it is determined that an eye not previously imaged is positioned to acquire a retinal image. In this regard, for patients with two eyes, method 600 is configured to acquire retinal images for both eyes.

[0077] Once a previously unimaged eye is positioned for retinal imaging, the method 600 includes obtaining a retinal image of the previously unimaged eye, as in process block 697 .

[0078] If the retinal image of the previously unimaged eye is acceptable, the method 600 includes storing the retinal image of the previously unimaged eye, as in process block 698 .

[0079] Certain processes described above are described with reference to computer software and hardware. The described techniques may constitute machine-executable instructions embodied in a tangible or non-transitory machine (e.g., computer) readable storage medium that, when executed by a machine, causes the machine to perform the described operations. Furthermore, the processes may be embodied in application specific integrated circuits ("ASICs") or other hardware, such as

[0080] 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 digital assistant, a manufacturing tool, any device with a set of one or more processors, etc.). For example, machine-readable storage media include 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.).

[0081] The above description of illustrated embodiments of the present invention, including what is described in the Abstract, is not intended to be exhaustive or to limit the invention to the precise form disclosed. While specific embodiments of and examples for the present invention have been described herein for illustrative purposes, those skilled in the art will recognize that various modifications are possible within the scope of the present invention.

[0082] These modifications 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 to limit the invention to the specific embodiments disclosed herein. Rather, the scope of the invention is to be determined entirely by the following claims, which are to be construed in accordance with established doctrines of claim interpretation.

Claims

1. 1. A retinal imaging system comprising: a monocular image sensor adapted to acquire a retinal image of the eye; a binocular eyepiece configured to slide relative to the monocular image sensor and shaped to couple to a user's face; Equipped with A retinal imaging system, wherein the monocular image sensor is positioned to acquire a first retinal image of a first eye of the user at a first position of the binocular eyepiece and to acquire a second retinal image of a second eye of the user at a second position of the binocular eyepiece.

2. a sliding bracket coupled to a housing of the retinal imaging system and slidably coupled to the binocular eyepieces; 10. The retinal imaging system of claim 1, wherein the sliding bracket defines a bracket opening, the bracket opening being shaped to allow light from inside the binocular eyepiece to pass through the bracket opening for reception by the monocular image sensor.

3. The retinal imaging system of claim 2 , wherein the bracket opening overlaps the monocular image sensor.

4. the binocular eyepieces include eyepiece reference markers; The sliding bracket is a first bracket reference marker aligned with the eyepiece reference marker when the binocular eyepieces are in the first position; a second bracket reference marker aligned with the eyepiece reference marker when the binocular eyepieces are in the second position; The retinal imaging system of claim 2 , comprising:

5. The retinal imaging system of claim 2 , wherein the sliding bracket is configured to move relative to the monocular image sensor along an imaging axis of the monocular image sensor.

6. further comprising at least two partition bars coupled to the sliding bracket; The retinal imaging system of claim 5 , wherein the at least two divider bars are slidably received by the housing and configured to move the sliding bracket relative to the housing along the imaging axis.

7. The binocular eyepieces are a frame slidably coupled to the sliding bracket; a compressible edge cushion disposed on an eye-facing edge of the frame and positioned to contact the face of the user; The retinal imaging system of claim 2 , comprising:

8. 8. The retinal imaging system of claim 7, wherein the frame defines a frame opening shaped to overlap with the bracket opening when the sliding bracket is coupled to the binocular eyepiece in both the first position and the second position.

9. 8. The retinal imaging system of claim 7, wherein the binocular eyepieces are shaped to fit at least a portion of the user's face, thereby limiting light entering the interior of the binocular eyepieces when the user's face is placed against the compressible edge cushion.

10. The retinal imaging system of claim 2 , wherein the curvature of the edges of the binocular eyepieces matches the curvature of the edges of the sliding brackets.

11. The housing is a first portion carrying the monocular image sensor; a second portion rotatably coupled to the first portion; The retinal imaging system of claim 2 , comprising:

12. the retinal imaging system comprises: a user interface configured to receive user input; a controller communicatively coupled to the monocular image sensor and the user interface; Further comprising: the controller includes logic that, when executed, causes the retinal imaging system to perform an operation; The operation is requesting placement of the binocular eyepieces in the first position using the user interface; determining laterality of a first eye of a subject; acquiring a retinal image of the first eye using the monocular image sensor; requesting, using the user interface, placement of the binocular eyepieces in a position to acquire a retinal image of the subject's second eye; acquiring a retinal image of the second eye using the monocular image sensor; The retinal imaging system of claim 1 , comprising:

13. The binocular eyepieces are a forehead rest shaped and positioned to contact the user's forehead when the user's face is positioned against the binocular eyepieces; a cheek rest shaped and positioned to contact the cheek of the user when the face of the user is positioned against the binocular eyepieces; Equipped with 10. The retinal imaging system of claim 1, wherein the forehead rest and cheek rest are shaped and positioned to induce a downward pitch of the user's head when the user's forehead and cheek are positioned against the binocular eyepieces.

14. 10. The retinal imaging system of claim 1, wherein the binocular eyepiece defines a cutout shaped to receive the user's nose when the user's face is positioned against the binocular eyepiece and to allow movement of the nose within the cutout.

15. 1. A retinal imaging adapter, comprising: a binocular eyepiece shaped to couple to a user's face; a sliding bracket configured to couple to a retinal imaging system and slidably coupled to the binocular eyepiece; Equipped with A retinal imaging adapter, wherein the sliding bracket defines a bracket opening, the bracket opening being shaped to allow light from inside the binocular eyepiece to pass through the bracket opening.

16. 16. The binocular eyepiece of claim 15, wherein the bracket opening is positioned such that, in a first position of the binocular eyepiece, light from a first eye of the user can pass through the bracket opening, and in a second position of the binocular eyepiece, light from a second eye of the user can pass through the bracket opening.

17. The binocular eyepiece of claim 15 , wherein the sliding bracket comprises a mounting attachment configured to be releasably attached to a housing of the retinal imaging system.

18. The binocular eyepieces a forehead rest shaped and positioned to contact the user's forehead when the user's face is positioned against the binocular eyepieces; a cheek rest shaped and positioned to contact the cheek of the user when the face of the user is positioned against the binocular eyepieces; Equipped with 16. The binocular eyepiece of claim 15, wherein the forehead rest and cheek rest are shaped and positioned to induce a downward pitch of the user's head when the user's forehead and cheek are placed against the binocular eyepiece.

19. 16. The binocular eyepiece of claim 15, wherein the binocular eyepiece defines a cutout shaped to receive the user's nose when the user's face is positioned against the binocular eyepiece and to allow movement of the nose within the cutout.

20. 1. A method of imaging a subject's retina using a retinal imaging system, the method comprising: requesting placement of binocular eyepieces of the retinal imaging system in a first position using a user interface of the retinal imaging system; determining laterality of a first eye of the subject; acquiring a retinal image of the first eye using a monocular image sensor of the retinal imaging system; requesting, using the user interface, placement of the binocular eyepieces in a position to acquire a retinal image of the subject's second eye; acquiring a retinal image of the second eye using the monocular image sensor; A method comprising:

Images