Retina selfie imager

Abstract

A self-administered retinal imager enables large-scale, decentralized "retina selfies" that can be performed by the subject themselves. The retinal imager can take the form of glasses with retinal imaging capabilities. The retinal imager will impact across multiple domains, such as cardiovascular, neurologic, 5 and ophthalmic health. Achieving population-level retinal screening also leverages and enables next generation machine learning analytics.

Description

RETINA SELFIE IMAGERCROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 746,511 filed on January 17, 2025, which is incorporated by reference, herein, in its entirety.FIELD OF THE INVENTION

[0002] The present invention relates generally to medical devices. More particularly, the present invention relates to a device for self-administered retinal imaging.BACKGROUND OF THE INVENTION

[0003] Imaging the retina provides important diagnostic information about the health of an individual. First, retinal imaging is often used to screen for blinding diseases. This screening is important because many blinding diseases are asymptomatic until the irreversible late stages. Second, the retina is a window to the brain and systemic vascular health.Researchers have shown that biomarkers in the retina can be used to predict cardiovascular events like stroke and neurodegenerative conditions like Alzheimer's Disease.

[0004] Currently, retinal imaging typically requires patients to visit a clinic for high quality retinal imaging. These eye care clinics use large and bulky equipment known as fundus imagers to photograph the retina. Generally, these clinical fundus imagers are expensive, immobile, and desktop-based platforms that only make sense in a clinical setting. However, they set the standard for retinal imaging performance. A challenge with the current approach is the relative infrequency and sparse sampling of the total population due to the need to visit an eye care facility'. More portable retinal imaging equipment exists, such ashandheld fundus imagers, but these devices have poor image quality and are difficult to operate, so they have not found significant share in the retinal imaging market. While handheld devices are more portable, they still require an operator separate from the patient. Clinical experience with these devices indicates they are difficult to operate and, when they do operate, produce poor quality images of the retina.

[0005] Accordingly, there is a need in the art for a high-quality', easy-to-use, selfadministered device for retinal imaging.SUMMARY OF THE INVENTION

[0006] The foregoing needs are met, to a great extent, by the present invention which provides a device for retinal imaging of a subject. The device includes a lens. The lens includes a metasurface, and the lens is configured to transmit light. An image sensor is used to capture light reflected from a retina of the subject to generate an image of the retina.

[0007] In accordance with another aspect of the present invention, the device includes a wearable frame for housing the lens and the image sensor. The device includes an illumination source configured to illuminate the retina The illumination source can take the form of a light emitting diode (LED). The illumination source is directed to illuminate the retina through the pupil. In other embodiments, the illumination source is directed to illuminate the retina through a pars plana region. The device can include a photonic crystal or metasurface-based filter. The device can also include a fixation target. The device can take the form of a pair of glasses in which the lens and image sensor are mounted. The device can include a housing for the lens and image sensor.

[0008] In accordance with an aspect of the present invention, a method of retinal imaging includes passing light through a lens toward a retina of a subject, wherein the lens comprisesa metasurface. The method includes transmitting the light passed through the lens and reflected off of the retina of the subject to an image sensor. The method includes capturing the light passed through the lens and reflected off of the retina of the subject with an image sensor to generate an image of the retina.

[0009] In accordance with an aspect of the present invention, the method includes generating the light with an illumination source configured to illuminate the retina. The method includes using a light emitting diode (LED) as the illumination source. The method includes directing the illumination source to illuminate the retina through a pupil. The method includes directing the illumination source to illuminate the retina through a pars plana region. The method includes using a photonic crystal filter. The method includes providing a fixation target. The method includes providing an angle of incidence filter configured to transmit light reflected from the retina while blocking illumination light reflected from a pars plana. The method includes using a housing for the lens and image sensor.BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The accompanying drawings provide visual representations, which will be used to more fully describe the representative embodiments disclosed herein and can be used by those skilled in the art to better understand them and their inherent advantages. In these drawings, like reference numerals identify corresponding elements and:

[0011] FIG. 1 illustrates a schematic diagram of a retinal imaging device, according to an embodiment of the present invention.

[0012] FIG. 2 illustrates a schematic diagram of a retinal imaging device with a custom contact lens, according to an embodiment of the present invention.

[0013] FIG. 3 illustrates a schematic diagram of a retinal imaging device, according to an embodiment of the present invention.

[0014] FIG. 4 illustrates a schematic diagram of a retinal imaging device, according to an embodiment of the present invention.

[0015] FIG. 5 illustrates a schematic diagram of a retinal imaging device, according to an embodiment of the present invention.

[0016] FIG. 6A illustrates a schematic diagram of a retinal imaging device, according to an embodiment of the present invention, and FIG. 6B illustrates a schematic diagram of a detailed metasurface-based optical design of the device illustrated in FIG. 6 A. FIG. 6C shows an alternative metasurface-based optical design for the embodiment of FIG. 6 A.

[0017] FIG. 7A illustrates a schematic diagram of a retinal imaging device, according to an embodiment of the present invention, and FIG. 7B illustrates a schematic diagram of a detailed optical design of the device illustrated in FIG. 7A.

[0018] FIG. 8A illustrates a schematic diagram of a retinal imaging device, according to an embodiment of the present invention, and FIG. 8B illustrates a schematic diagram of a detailed optical design of the device illustrated in FIG. 8 A.

[0019] FIG. 9A illustrates a schematic diagram of a retinal imaging device, according to an embodiment of the present invention, and FIG. 9B illustrates a schematic diagram of a detailed optical design of the device illustrated in FIG. 9 A.

[0020] FIG. 10 illustrates a schematic diagram of an exemplary’ metasurface, according to an embodiment of the present invention.

[0021] FIG. 11 illustrates a graphical view of imaging performance of the device for retinal imaging illustrated in FIG. 6A.

[0022] FIG. 12 illustrates a diagrammatic view of imaging performance of the device for retinal imaging illustrated m FIG. 6A.

[0023] FIG. 13 illustrates a schematic diagram of a detailed optical design for another embodiment of a retinal imaging device, according to an embodiment of the present invention.

[0024] FIGS. 14A-14G illustrate a schematic diagram of a retinal imaging device, according to an embodiment of the present invention.

[0025] FIGS. 15A-15D illustrate a schematic diagram of a retinal imaging device, with an added angle of incidence (Aol) filter, according to an embodiment of the present invention.

[0026] FIGS. 15F and 15G illustrate an AoI filter as a custom filter that changes as a function of position on the filter.DETAILED DESCRIPTION

[0027] The presently disclosed subject matter now will be described more fully hereinafter with reference to the accompanying Drawings, in which some, but not all embodiments of the inventions are shown. Like numbers refer to like elements throughout. The presently disclosed subject matter may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein: rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Indeed, many modifications and other embodiments of the presently disclosed subject matter set forth herein will come to mind to one skilled in the art to which the presently disclosed subject matter pertains having the benefit of the teachings presented in tire foregoing descriptions and the associated Drawings. Therefore, it is to be understood that the presently disclosed subject matter is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims.s

[0028] The present invention is directed to a self-administered retinal imager. This is a novel imaging platform that will enable large-scale, decentralized, "retina selfies" that can be performed by the subject themselves. In some embodiments, the present invention can take the form of glasses with retinal imaging capabilities. The device of the present invention will have an impact across multiple domains, such as cardiovascular, neurologic, and ophthalmic health. Achieving population-level retinal screening also enables next generation machine learning analytics.

[0029] The present invention can take a number of different forms, but each provides a necessary' field of view and imaging resolution, while preventing degradations from stray reflections of the illumination light from the air-cornea interface, often called the corneal reflex. Next generation optics can be used to enable a much smaller form factor with improved capability' compared to existing solutions.

[0030] Any of the embodiments of the present invention will be portable (similar to handheld fundus imagers) but will also have high-quality' imaging performance. Devices according to the present invention will have a much smaller size and weight compared to existing technology'. Devices according to the present invention will be self-operated. This means that the device can be operated by the patient, a second person is not needed. All known commercial fundus imagers require a second person to operate. Devices according to the present invention will include a processor running existing AI / ML algorithms for retinal screening. Existing technologies generally don't have on-board, image processing capabilities.

[0031] FIG. 1 illustrates a schematic diagram of a retinal imaging device, according to an embodiment of the present invention. The retinal imaging device 10 illustrated in FIG. 1 includes an over-the-eye wearable frame 12. such as that of spectacles, goggles, or otherover-the-eye wearable known to or conceivable to one of skill in the art. The retinal imaging device 10 includes a number of components to allow for high-quality retinal imaging. The device 10 includes light emitting diodes (LEDs) 14 and 16 that illuminate the eye 18. Ihe light emitted from the LEDs follows illumination paths 20 and 22. The light in the illumination paths 20 and 22 passes through one of two condenser lenses 24 and 26, respectively. The condenser lenses may include a metasurface. The condenser lenses 24 and 26 are optimized for the transmission of light from the LEDs 14 and 16 along the illumination paths 24 and 26 until it reaches the retina 28. The retina 28 reflects the light back along imaging paths 30, 32, 34. The imaging paths 30. 32, 34 exit the eye 18 and are imaged through lenses 36 and 38 before reaching the image sensor 40. The image sensor 40 uses the data from the light reflected back from the retina 28 to generate an image view of the retina 28.

[0032] FIG. 2 illustrates a schematic diagram of a retinal imaging device with a custom contact lens, according to an embodiment of the present invention. The retinal imaging device 10 illustrated in FIG. 2 includes an over-the-eye wearable frame 12, such as that of spectacles, goggles, or other over-the-eye wearable known to or conceivable to one of skill in the art. The retinal imaging device 10 includes a number of components to allow7for high- quality7retinal imaging. The device 10 includes light emitting diodes (LEDs) 14 and 16 that illuminate the eye 18. The light emitted from the LEDs follows illumination paths 20 and 22. The light in the illumination paths 20 and 22 passes through one of two condenser lenses 24 and 26. respectively. The condenser lenses may include a metasurface. Lenses 24 and 26 are optimized for the transmission of light from the LEDs 14 and 16 along the illumination paths 24 and 26 until it reaches the retina 28. A custom contact lens 29 is positioned on the surface of the eye 18. The custom contact lens 29 reduces reflection from the cornea and allows forthe over-the-eye frame 12 to be positioned further from the eye 18, providing eye relief for some users. The retina 28 reflects the light back along imaging paths 30, 32, 34. The imaging paths 30, 32, 34 exit the eye 18 and are imaged through the contact lens 29 and imaging lenses 36 and 38, before reaching the image sensor 40. The imaging sensor 40 uses the data from the light reflected back from the retina 28 to generate an image view of the retina 28. The contact lens 29 can allow for a larger retinal field of view, and better accommodation for eye orientation and focus.

[0033] FIG. 3 illustrates a schematic diagram of a retinal imaging device, according to an embodiment of the present invention. The retinal imaging device 100 illustrated in FIG. 3 includes an over-the-eye wearable frame 112, such as that of spectacles, goggles, or other over-the-eye wearable known to or conceivable to one of skill in the art. The retinal imaging device 100 includes a number of components to allow for high-quality7retinal imaging. The device 100 includes light emitting diodes (LEDs) 114 and 116 that illuminate the eye 118. The light emitted from the LEDs follows an illumination path 120 and 122. The light in the illumination paths 120 and 122 passes through one of two condenser lenses 124 and 126, respectively. The condenser lenses 124, 126 may include a metasurface. The condenser lenses 124 and 126 are optimized for the transmission of light from the LEDs 114 and 116 along the illumination paths 120 and 122 until it reaches the retina 128. In FIG. 3, the condenser lenses 124 and 126 are configured to direct the illumination paths 120 and 122 through the pupil 102. Polarizers 104, 106 are positioned on the condenser lenses 124, 126. The illumination paths 120 and 122 pass through the condenser lenses 124. 126 and subsequently through the polarizers 104, 106. The retina 128 reflects the light back along imaging paths 130. 132, 134. The imaging paths 130, 132, 134 exit the eye 118 and are filtered through a crossed polarizer 108, imaging lenses 136, 138. a dichroic beamsplitter110, and a cleanup filter 142, before reaching the image sensor 140. The image sensor 140 uses the data from the light reflected back from the retina 128 to generate an image view of the retina 128.

[0034] As illustrated in FIG. 3, for efficient illumination of the retina, the light emitted from the LED is directed through the pupil. The dichroic beamsplitter 110 is used to aid in clarity of the fixation target (not shown). The metasurfaces of the condenser lenses 124 and 126 is used to focus and deflect LED illumination from the LEDs 114 and 116 into the pupil 102. The cleanup filter 142 is used to remove any residual light from the fixation target (not shown). The crossed polarizer 108 is used to eliminate ghost reflections from illumination subsystem. In some embodiments, the LEDs 114 and 116 can be sequenced so any ghost reflection would move between subsequent frames.

[0035] FIG. 4 illustrates a schematic diagram of a retinal imaging device, according to an embodiment of the present invention. The retinal imaging device 200 illustrated in FIG. 4 is configured to be positioned in front of an eye of the user of the device. The retinal imaging device 200 includes a number of components to allow for high-quality retinal imaging. The eye 218 is illuminated around the iris with pars plana illumination via LEDs that are positioned off to the side and are not shown in this figure. An exemplary wavelength would be 850 nm, but any wavelength known to or conceivable to one of skill in the art could also be used. In some embodiments, a VIS-NIR wavelength is used. A fixation target 244 is positioned on the outside of the device 200. A lens 202 is positioned between the fixation target 244 and the eye 218 of the subject. The lens 202 includes a metasurface 204 positioned on a surface of the lens 202 between the lens 202 and the fixation target 244. A dichroic beamsplitter 210 and a cross polarizer 208 are positioned at an angle (0) to one another, where the dichroic beamsplitter 210 is positioned on a surface of the lens between the eyedichroic beamsplitter 210 and the eye 208. A total internal reflector 212 combines with the dichroic beamsplitter 210 and the cross polarizer to reflect the light exiting the eye, through cleanup filter 242 and ultimately to the image sensor 240. The image sensor 240 uses the data from the light reflected back from the retina to generate an image view of the retina.

[0036] Further with respect to FIG. 4, for the pars plana illumination polarized LEDs would be placed to the sides of the prism and imaged to the pars plana region to diffuse illumination inside the eye. While an 850 nm wavelength is used as an exemplary wavelength herein, any wavelength known to or conceivable to one of skill in the art could be used. The fixation target 244 is an object for the eye to focus on during the imaging. The cross polarizer 208 is configured to block specular reflections of pars plana illumination. The dichroic beamsplitter 210 is configured for passing the visible fixation target and reflecting NIR light from retina. The cleanup filter 242 is configured to reject any visible light from the fixation target and ambient sources.

[0037] FIG. 5 illustrates a schematic diagram of a retinal imaging device, according to an embodiment of the present invention. The retinal imaging device 300 illustrated in FIG. 5 includes an over-the-eye wearable frame 312, such as that of spectacles, goggles, or other over-the-eye wearable known to or conceivable to one of skill in the art. The retinal imaging device 300 includes a number of components to allow for high-quality retinal imaging. The device 300 includes light emitting diodes (LEDs) 314 and 316 that illuminate the eye 318. The light emitted from the LEDs follows an illumination path 320 and 322. The light in the illumination paths 320 and 322 pass through one of two polarizers 304 and 306, respectively. The polarizers 304 and 306 include an illumination metasurface 329 and 331. The illumination metasurfaces 329 and 331 of the polarizers 304 and 306 are optimized for thetransmission of light from the LEDs 314 and 316 along the illumination paths 320 and 322 until it reaches the retina. In FIG. 5, the polarizer 304 and 306 along with the illumination metasurfaces 329 and 331 are configured to direct the illumination paths 320 and 322 for pars plana illumination. A fixation target 344 is positioned for the eye to focus on during the imaging. The light from the fixation target 344 passes through a lens 346 having a fixation metasurface 348 on a side closest to the fixation target 344 and a combiner metasurface 350 on the opposite side. Light from the fixation target 344 is projected into the eye through the fixation metasurface 348 to keep the eye stable and focused at infinity.

[0038] The retina reflects the light back along imaging paths. The imaging paths exit the eye 318 and the light is reflected by the combiner metasurface 348. The light travels along the imaging paths through a crossed polarizer 308, imaging stop 352, imaging lenses 354 and 356, and a cleanup filter 358, before reaching the image sensor 340. The crossed polarizer 308 is configured to reduce stray light from the illumination subsystem. The cleanup filter 358 is used to reject any light from the fixation target. The image sensor 340 uses the data from the light reflected back from the retina to generate an image view of the retina. In this embodiment, the image sensor 340 is positioned by the temple of the user.

[0039] FIG. 6A illustrates a schematic diagram of a retinal imaging device, according lo an embodiment of the present invention, and FIG, 6B illustrates a schematic diagram of a detailed metasurface-based optical design of the device illustrated in FIG. 6A. FIG. 6C illustrates a schematic diagram an alternative metasurface-based concept design, according to the embodiment of FIG, 6A. The retinal imaging device 400 illustrated in FIGS. 6A and 6B includes an over-the-eye wearable frame 412, such as that of spectacles, goggles, or other over-the-eye wearable known to or conceivable to one of skill in the art. The retinal imagingdevice 400 includes a number of components to allow for high-quality retinal imaging. The device 400 includes light emitting diodes (LEDs) 414 and 416 that illuminate the eye 418. The light emitted from the LEDs follows an illumination path 420 and 422. The light in the illumination paths 420 and 422 passes through one of two condenser lenses 424 and 426, respectively. The condenser lenses 424, 426 may include a metasurface. The condenser lenses 424 and 426 are optimized for the transmission of light from the LEDs 414 and 416 along the illumination paths 420 and 422 until it reaches the retina 428.

[0040] In FIGS. 6A and 6B, the condenser lenses 424 and 426 are configured to direct the illumination paths 420 and 422 for pars plana illumination. Polarizers 404, 406 are positioned on the condenser lenses 424, 426. The illumination paths 420 and 422 pass through the condenser lenses 424, 426 and subsequently through the polarizers 404, 406. The retina 428 reflects the light back along imaging paths 430, 432, 434. The imaging paths 430, 432, 434 exit the eye 418 and are filtered through a crossed polarizer 408. imaging lenses 436, 438, a dichroic beamsplitter 410, and a cleanup filter 442, before reaching the image sensor 440. The image sensor 440 uses the data from the light reflected back from the retina 428 to generate an image view of the retina 428.

[0041] As illustrated in FIGS. 6A and 6B, for illumination of the retina, the light emitted from the LED is directed through the pars plana region providing diffuse illumination of the retina. The dichroic beamsplitter 410 is used to aid in clarity of the fixation target (not shown). The metasurfaces of the condenser lenses 424 and 426 are used to focus and deflect LED illumination from the LEDs 414 and 416 into the pupil 402. The cleanup filter 442 is used to remove any residual light from the fixation target (not shown). The crossed polarizer 408 is used to eliminate ghost reflections from illumination subsystem. In some embodiments, the LEDs 414 and 416 can be sequenced so any ghost reflection would movebetween subsequent frames. FIG. 6C shows an alternative metasurface-based optical design for the embodiment of FIG. 6A. The configuration shown in FIG. 6C adds a relay system for a controllable external stop and allows for some change in magnification.

[0042] FIG. 7 A illustrates a schematic diagram of a retinal imaging device, according to an embodiment of the present invention, and FIG. 7B illustrates a schematic diagram of a detailed optical design of the device illustrated in FIG. 7 A. The retinal imaging device 500 illustrated in FIGS. 7A and 7B is configured to be positioned in front of an eye of the user of the device and includes an over-the-eye wearable frame 512, such as that of spectacles, goggles, or other over-the-eye wearable known to or conceivable to one of skill in the art. The retinal imaging device 500 includes a number of components to allow for high-quality retinal imaging. The eye 518 is illuminated through the pupil by an fixation target 544. A first lens pair 502 and a first dichroic beamsplitter 510 are positioned between the fixation target 544 and the eye 518 of the subject. An optional polarizer 508 can be positioned between the eye 518 and the first lens pair 502. A laser source 568 also directs light through a fourth lens 570 and the second dichroic beamsplitter 566 to the MEMS scanner 505. This MEMS scanner translates the laser focus on the retina. The retina of the eye 518 reflects the illuminating laser light back through the first lens pair 502 and is reflected at a 90° angle by the dichroic beamsplitter 510. The reflected laser light then travels through a second lens pair 503, a MEMS scanner 505, a beamsplitter 566, a pinhole 562 before arriving at an avalanche photodiode 560, which measures the amount of laser light being reflected from that area of the retina.

[0043] Further with respect to FIGS. 7A and 7B, a spectacles-based implementation of a scanning laser ophthalmoscope is illustrated The scanning is performed by a MEMS-based scanner 505. The MEMS scanner needs to be high speed in one direction and relatively low-speed in the other direction. In some embodiments, the fast scanning could be done with a tunable laser and grating. The pinhole filter 562 and APD collect light only near the laser focus to provide better contrast. A fixation target 544 allows for the orientation of the eye 518 by placing the target anywhere on the chip. This embodiment provides better contrast in near infrared than conventional fundus imaging and is less susceptible to corneal reflex. In some embodiments a beam diameter of 2mm at the pupil of the eye and a FFOV between 30° and 45° is used. An alternative would be to use polarization to hit the MEMS mirror at 0° rather than 45° so there isn't the 30% reduction in beam diameter in that axis of the beam.

[0044] Further with respect to the system of FIGS. 7A and 7B, the system is raster scanning a laser on the retina using the MEMS scanner. Simultaneously, the system monitors how much light is being reflected from that small focus of the laser on the retina. So as the system is scanning, a map of how much light is being reflected is being built as a function of position on the retina. In an imaging system, the amount of light from all positions on the retina is measured simultaneously. In the scanning solution, the amount of light from one position is measured at a time such that a final image can be constructed only after the entire retina has been scanned. This might take something like 1 / 10 of sec to scan the retina, depending on the MEMS scanner being used.

[0045] FIG. 8A illustrates a schematic diagram of a retinal imaging device, according to an embodiment of the present invention, and FIG. 8B illustrates a schematic diagram of a detailed optical design of the device illustrated in FIG. 8 A, The retinal imaging device 600 illustrated in FIGS. 8A and 8B includes an over-the-eye wearable frame 612, such as that of spectacles, goggles, or other over-the-eye wearable known to or conceivable to one of skill in the art. The retinal imaging device 600 includes a number of components to allow for high-quality retinal imaging. The device 600 includes light emitting diodes (LEDs) 614 and 616 that illuminate the eye 618. The light emitted from the LEDs follows an illumination path 620 and 622. The light in the illumination paths 620 and 622 passes through one of two lenses 624 and 626, respectively.b

[0046] In FIGS. 8 A and 8B, the lenses 624 and 626 are configured to direct the illumination paths 620 and 622 for pars plana illumination. The retina 628 reflects the light back along imaging paths 630, 632, 634. The imaging paths 630, 632, 634 exit the eye 618 and are filtered through a lens 608. The light is reflected off of beamsplitter 610 and mirror 611 before it is passed through a stop 613, second lens 615, and a third lens 617 to image 0 sensor 640. Lenses 608, 615. and 617 may have metasurfaces.

[0047] A fixation target 642 is positioned for the eye to focus on during the imaging. The light from the fixation target 642 passes through the dichroic beamsplitter 610 and metasurface lens 608. Light from the fixation target 642 is projected into the eye through the metasurface lens 608 to keep the eye stable and focused at infinity

[0048] FIG. 9A illustrates a schematic diagram of a retinal imaging device, according to an embodiment of the present invention, and FIG. 9B illustrates a schematic diagram of a detailed optical design of the device illustrated in FIG. 9 A. Ihe retinal imaging device 700 illustrated in FIGS 9A and 9B includes an over-the-eye wearable frame 712, such as that of spectacles, goggles, or other over-the-eye wearable known to or conceivable to one of skill in 0 the art. The retinal imaging device 700 includes a number of components to allow’ for high- quality retinal imaging. The device 700 includes light emitting diodes (LEDs) 714 and 716 that illuminate the eye 718. The light emitted from the LEDs follow’s an illumination path 720 and 722. The light in the illumination paths 720 and 722 passes through one of two condenserlenses 724 and 726, respectively. The condenser lenses 724, 726 include a metasurface. The metasurface of the condenser lenses 724 and 726 is optimized for the transmission of light from the LEDs 714 and 716 along the illumination paths 720 and 722 until it reaches the retina 728.

[0049] In FIGS. 9 A and 9B, the condenser lenses 724 and 726 are configured to direct the illumination paths 720 and 722 for pars plana illumination. Polarizers 704, 706 are positioned on the condenser lenses 724, 726. The illumination paths 720 and 722 pass through the condenser lenses 724, 726 and subsequently through the polarizers 704, 706. The retina 728 reflects the light back along imaging paths 730, 732. 734. The imaging paths 730, 732, 734 exit the eye 718 and are filtered through a polarizer 708, imaging lenses 736, 738, and a dichroic beamsplitter 710. The light is then reflected off of a first mirror 703, a quarter waveplate 705, and a second mirror or stop 707 to image sensor 740. The image sensor 740 uses the data from the light reflected back from the retina 728 to generate an image view of the retina 728.

[0050] As illustrated m FIGS. 9A and 9B, for illumination of the retina, the light emitted from the LED is directed through the pars plana region providing diffuse illumination of the retina. The dichroic beamsplitter 710 is used to aid m clarity of the fixation target (not shown). The metasurfaces of the condenser lenses 724 and 726 are used to focus and deflect LED illumination from tire LEDs 714 and 716 into the pupil 702. The cleanup filter 742 is used to remove any residual light from the fixation target (not shown). The polarizer 708 is used to eliminate ghost reflections from illumination subsystem. In some embodiments, the LEDs 714 and 716 can be sequenced so any ghost reflection would move between subsequent frames. A physical stop 707 helps reject stray ghost reflections from reaching the image sensor.

[0051] In embodiments where pars plana illumination is used an angular selective filter, called a photonic cry stal filter can be added. This filter blocks reflections from the pars plana from reaching the image sensor and degrading the image. The stray light can potentially degrade or overwhelm the weak light returning from the retina.

[0052] FIG. 10 illustrates a schematic diagram of an exemplary' metasurface, according to an embodiment of the present invention. For the metalens, a conventional approach associated with the design of the 2D structure is implemented. The process starts with the calculation of the lens phase profile, referred to as Φ(x,y), at the design frequency of interest, where x and y represent the spatial coordinates along the metalens surface. The target-phase profile is usually obtained by using either ray tracing software (e.g., OpticStudio from Zemax) or a Fourier-optics method to implement the focusing function found in a conventional lens. The next design step is construction of a library of nanostructures that are used to subsequently populate d>(x.y) Construction of the library' requires the use of a fullwave simulation solver to connect a given nanostructure geometry to the phases that it can provide, e.g., CST Microwave Studio. Common choices of nanostructures within a metalens are circular, square, or cross-shaped pillars, whose geometric parameters are varied to cover a range of 2n phase delays with high transmission, in some embodiments the nanostructures can take the form of a single layer of SiNx cylindrical posts in a hexagonal lattice arrangement. A Si-rich SiNx can m some embodiments be used as the metasurface material, which has a good transparency window from ~ 600 to > lOOOnm. High quality', large area metasurfaces of this material have been demonstrated in the visible to near IR region of the spectrum. As a secondary material. TiO2could be used but the development time for this system would be longer than the SiNx metasurface. Both materials can use glass as a substrate or a low-index substrate such as MgF2.

[0053] Ihe last step of the metasurface design is the digitization of the target phase Φ(x,y) and the selection of nanostructures from the library that best match Φ(x;,;) at each location within the metalens. This selection process typically requires an optimization algorithm for the identification of the unit cell within the library. Since the size of a metalens is usually on the order of millimeters to centimeters, the number of nanostructures within the structure can be very large, owing to their sub-wavelength size and spacing An efficient algorithm is, therefore, required to produce layout files for nanolithography machines.

[0054] In some embodiments, it may be advantageous to design a metasurface capable of transmitting rays with certain k-vectors, while absorbing other k-vectors. Such a metasurface could allow for bright reflections from the pars planar region to be eliminated. Eliminating stray light reflecting from the pars planar region could also be achieved by stacking a series of metasurfaces configured for absorbing the stray light reflections.

[0055] Metasurface optics introduce a desired amplitude or phase change to an incident beam of light. The metasurface consists of a periodic array of custom nanostructures - each structure designed to modify the incident beam of light in some prescribed matter.Metasurfaces have the potential to be mass produced similar to injection molded glass and plastic lenses.

[0056] FIG. 11 illustrates a graphical view of imaging performance of the device for retinal imaging illustrated in FIG. 6A, and FIG. 12 illustrates a diagrammatic view of imaging performance of the device for retinal imaging illustrated m FIG. 6A. The device of FIG. 6A and 6B has good imaging performance for a 4mm diameter aperture (see spot diagram to right showing diffraction limited at 850nm, while an 850 nm wavelength is used herein, this is simply by way of example and any suitable wavelength known to or conceivable to one of skill in the art could also be used).

[0057] FIG. 13 illustrates a graphical view of the relationship between mirror diameter and scan angle for the device for retinal imaging of FIG. 7 A. The plot of FIG. 13 shows how the MEMS mirror diameter and the maximum mechanical angle of the MEMS impact the scan size. The best COTS MEMS option available is the Hamamatsu which would provide a scan angle of ±12.3° or 24.6° scan size. The Hamamatsu MEMS mirror is one of the only commercial options that has the necessary speed requirements.

[0058] FIGS. 14A-14G illustrate a schematic diagram of a retinal imaging device, according to an embodiment of the present invention. The embodiment illustrated in FIGS.14A-14G uses through pupil illumination. As illustrated in FIG. 14A, the imaging relay creates virtual LED sources in the pupil of the eye, which then illuminate tire retina (yellow ray bundles). Simultaneously, the optical systems creates an image of the retina and then creates a virtual image that is imaged by the MIP1 camera (red ray bundles). This pupil plane includes a ring of LED illuminators around a central aperture where the cell phone camera is located (MIPI camera) The MIPI camera has autofocus to accommodate for eyes with different focal lengths.

[0059] As illustrated in FIG. 14B, a paraxial version of the embodiment of FIG. I4A can also be used. The variation of FIG. 14C illustrates a version with 1mm thick metasurface optics. Notice the off axis is out of focus at the image plane. This could be adjusted with (a) higher order phase profile terms or (b) adding curvature to the nonmetasurface side of the lens. FIG. 14D illustrates a higher Order Phase Profile. Note that the higher order phase profile does a poorjob at fixing the off-axis imaging performance. FIG. 14E illustrates added curvature and thickness to non-meta side of lens. FIG I4F illustrates added extra phase terms and re-optimization, which had a negligible effect on the performance. FIG. 14G illustrates aMIPI camera f / 2.2 with f=3.81mm and reoptimized. FIG. 14G also illustrates addition of two wavelengths (550 and 650nm). The PCX lens has a focal length of 30mm and a diameter of 16mm.

[0060] FIGS. 15A-15D illustrate a schematic diagram of a retinal imaging device, with an added angle of incidence (Aol) filter, according to an embodiment of the present invention. FIG. 15 A illustrates an Aol filter with a pass band between 16 and 24 ° Aol. FIGS. 15B and 15C show an illuminated sclera m the shaded model to the left. The longer illumination area was first chosen to get more light to the retina (due to a peak irradiance limitation). However, the longer region may increase the blocking angular range of the filter. FIGS. 15D and 15E show an illumination sliver reduced from - 12 mm to ~ 4mm long to improve the Aol distribution. FIGS. 15F and 15G illustrate an Aol filter as a custom filter that changes as a function of position on the filter. The layout of the ray tracing analysis is shown to the left in FIG. 15G. Ihere are two filters (A and B) but using symmetry of the shows that the filters are equivalent (but flipped). The coordinate system is shown where XY is at the center of the 9.4 x 18mm filter. X points away from the eye. Y points down (into slide) but the filter response is symmetric with respect to Y so the exact direction isn’t important. FIGS. 15A-15D illustrate one embodiment of the present invention, but other embodiments could be envisioned to those skilled in the art, for example, placing the Aol filter immediately in front of the image sensor. Function of the present invention can be carried out in conjunction with a computer, smartphone, tablet, processor device, non-transitory computer readable medium, or alternately a computing device or non-transitory computer readable medium incorporated into the medical device associated with the present invention.

[0061] A non-transitory computer readable medium is understood to mean any article of manufacture that can be read by a computer. Such non-transitory computer readable media includes, but is not limited to, magnetic media, such as a floppy disk, flexible disk, hard disk, reel-to-reel tape, cartridge tape, cassette tape or cards, optical media such as CD-ROM, writable compact disc, magneto-optical media in disc, tape or card form, and paper media, such as punched cards and paper tape. The computing device can be a special computer designed specifically for this purpose. The computing device can be unique to the present invention and designed specifically to carry out the method and operation of the present invention.

[0062] In some embodiments machine learning and artificial intelligence can be used to analyze and improve the image of the retina Analysis can also include scanning for biomarkers of comorbidities such as diabetes, neurogenerative diseases, and other blinding illnesses.

[0063] The many features and advantages of the invention are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirit and scope of the invention.Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention While exemplary embodiments are provided herein, these examples are not meant to be considered limiting. The examples are provided merely as a way to illustrate the present invention. Any suitable implementation of the present invention known to or conceivable by one of skill in the art could also be used.

Claims

1. What is claimed is:

1. A device for retinal imaging of a subject comprising:a lens, wherein the lens comprises a metasurface, and wherein the lens is configured to transmit light;b an image sensor to capture light reflected from a retina of the subject to generate an image of the retina.

2. The device of claim 1 further comprising a wearable frame for housing the lens and the image sensor.

3. The device of claim 1 further comprising an illumination source configured to 0 illuminate the retina.

4. The device of claim 3 wherein the illumination source comprises a light emitting diode (LED).

5. The device of claim 3 wherein the illumination source is directed to illuminate the retina through a pupil.5 6. The device of claim 3 wherein the illumination source is directed to illuminate the retina through a pars plana region.

7. The device of claim 6 further comprising a photonic crystal filter.

8. The device of claim 1 further comprising a fixation target.

9. The device of claim 1 further comprising an angle of incidence filter configured to 0 transmit light reflected from the retina while blocking illumination light reflected from the pars plana.

10. The device of claim 1 further comprising a pair of glasses in which the lens and image sensor are mounted.

11. The device of claim 1 further comprising a housing for the lens and image sensor.

12. A method of retinal imaging comprising:passing light through a lens toward a retina of a subject, wherein the lens comprises a metasurface;transmitting the light passed through the lens and reflected off of the retina of the subject to an image sensor;capturing the light passed through the lens and reflected off of the retina of the subject with an image sensor to generate an image of the retina.

13. The method of claim 12 further comprising generating the light with an illumination source configured to illuminate the retina.

14. The method of claim 13 further comprising using a light emitting diode (LED) as the illumination source.

15. The method of claim 13 further comprising directing the illumination source to illuminate the retina through a pupil.16 The method of claim 13 further comprising directing the illumination source to illuminate the retina through a pars plana region.

17. The method of claim 16 further comprising using a photonic crystal filter.

18. The method of claim 12 further comprising providing a fixation target.

19. The method of claim 12 further comprising providing an angle of incidence filter configured to transmit light reflected from the retina while blocking illumination light reflected from a pars plana.

20. The method of claim 13 further comprising using a housing for the lens and image sensor.

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