Retinal cellscope apparatus

Abstract

A handheld, ocular imaging device and system that employs the camera, processor and programming of a mobile phone, tablet or other smart device coupled to optical elements and illumination elements that can be used to image the structures of the eye in non-clinical locations, for example is presented. The modular device provides multi-functionality (fluorescein imaging, fluorescence, brightfield, infrared (IR) imaging, near-infrared (NIR) imaging) and multi-region imaging (retinal, corneal, external, etc.) of the eye along with the added features of image processing, storage and wireless data transmission for remote storage and evaluation. Acquired ocular images can also be transmitted directly from the device to the electronic medical records of a patient without the need for an intermediate computer system.

1 . A portable, ocular imaging system, comprising:
 (a) an image acquisition unit comprising:
 (i) a first set of optical elements positioned at a proximal section of the unit, said first set of optical elements including a first polarizer; and 
 (ii) a second set of optical elements spaced distally relative to the first set of optical elements and aligned along an optical axis defining an imaging path; 
 (iii) wherein said first polarizer is positioned in the imaging path; 
   (b) an illumination unit comprising:
 (i) a light source configured to emit light along an illumination path to illuminate a target disposed along the optical axis of the second set of optical elements; and 
 (ii) a second polarizer; 
 (iii) wherein the second polarizer is positioned in the illumination path and wherein the second polarizer is crossways to the first polarizer; 
   (c) an imaging unit, comprising:
 (i) a camera sensor optically coupled to the first set of optical elements of the image acquisition unit along the optical axis; 
 (ii) a computer processor coupled to the camera sensor; and 
 (iii) programming residing in a non-transitory computer readable medium, wherein the programming is executable by the computer processor and configured to capture illuminated images of the target from the camera sensor; and 
 (iv) a computer readable memory for storing captured images of the target. 
   
     
     
         2 . An imaging system as recited in  claim 1 :
 wherein the first set of optical elements of the acquisition unit further comprises a relay lens; and   wherein the second set of optical elements comprises an ophthalmic lens.   
     
     
         3 . An imaging system as recited in  claim 1 , said image acquisition unit further comprising a filter selected from the group of filters consisting of a glass filter, a bandpass filter, a longpass filter, and a shortpass filter. 
     
     
         4 . An imaging system as recited in  claim 1 , wherein said illumination unit further comprises:
 a collector lens configured to collect light from the light source and focus it on the plane of the second polarizer; and   a condenser lens configured to concentrate light from the second polarizer onto a beam splitter disposed between the first set of optical elements and the second set of optical elements and in the optical axis of the image acquisition unit;   wherein polarized light from the light source is divided by the beam splitter and transmitted out through the second set of optical elements to illuminate the target.   
     
     
         5 . An imaging system as recited in  claim 4 , wherein said illumination unit further comprises a diffuser interposed between the collector lens and the second polarizer. 
     
     
         6 . An imaging system as recited in  claim 5 , wherein said illumination unit further comprises a mask interposed between the second polarizer and the condenser lens. 
     
     
         7 . An imaging system as recited in  claim 1 :
 wherein said illumination unit further comprises a power supply circuit coupled to the light source and controlled by the programming of the imaging unit; and   wherein actuation and duration of the light source is controlled by the programming.   
     
     
         8 . An imaging system as recited in  claim 1 , wherein the light source comprises one or more light emitting diodes (LED). 
     
     
         9 . An imaging system as recited in  claim 1 , wherein the light source comprises:
 one or more light emitting diodes (LED) that emit light in the far red region (650 nm-750 nm); and   one or more white light emitting diodes (LED);   wherein the far red LED is configured to provide “preview” illumination;   wherein the far red LED is configured to set the focus of the system; and   wherein the far red LED is configured for intensity to be increased to set the exposure to the same level as the white LED.   
     
     
         10 . An imaging system as recited in  claim 1 , wherein the light source comprises at least one LED that emits light in a wavelength that will excite a fluorescent dye selected from the group of the blue region 450 nm-500 nm, the violet region 400 nm-450 nm, and the ultraviolet (UV) region 200 nm-400 nm. 
     
     
         11 . An imaging system as recited in  claim 1 , wherein said illumination unit further comprises a wireless receiver configured to receive wireless control commands from the imaging unit computer processor programming. 
     
     
         12 . An imaging system as recited in  claim 1 , further comprising:
 a communications unit with at least one transmitter and receiver for transmitting captured and processed images and receiving data from a remote source through wired or wireless transmissions.   
     
     
         13 . An imaging system as recited in  claim 1 , wherein the second set of optical elements comprises an objective lens having a diopter selected from the group consisting of a diopter≥1, a diopter≥5, a diopter≥10, a diopter≥15, a diopter≥30; and a diopter≥50. 
     
     
         14 . An imaging system as recited in  claim 1 , wherein the light source comprises:
 one or more light emitting diodes (LED) that emit white light, light in the infrared region, or light in the far red region; and   wherein captured IR, far red, and color images are overlaid and compared by the programming to identify any features that are visible in one illumination wavelength that may not be detected in the other illumination wavelengths thereby providing for multi-spectral imaging.   
     
     
         15 . An imaging system as recited in  claim 1 , wherein the light source comprises one or more light emitting diodes (LED) with emissions>700 nm that are outside the scotopic and photopic response region of the eye that decrease pupillary constriction of the eye to allow a wider opening for imaging through the pupil and to avoid the need for pharmacological dilators. 
     
     
         16 . An imaging system as recited in  claim 1 , wherein the light source comprises at least one blue LED with 400 nm to 500 nm peak emissions to image based on the autofluorescence of the retina. 
     
     
         17 . An imaging system as recited in  claim 1 , further comprising one or more light emitting diodes that are positioned off axis at a position in the optical path that provides a fixation point for the subject being photographed to fixate on to allow specific regions of the retina to be imaged. 
     
     
         18 . An imaging system as recited in  claim 1 :
 wherein said system is configured to direct an annulus of light at or near the eye pupil;   wherein the annulus is focused sufficiently to penetrate the cornea, anterior compartment, and lens while in focus, but defocused by the time it gets to the retina so that the illumination is uniform.   
     
     
         19 . An imaging system as recited in  claim 1 , wherein said programming further comprises a feedback loop between the imaging unit and the illumination unit to alter image characteristics by modifying the intensity of the light source. 
     
     
         20 . An imaging system as recited in  claim 1 , wherein said programming further comprises a feedback loop between the imaging unit and the illumination unit to determine regions of the retina that are being imaged so that regional images can be compiled to show the entire field of the retina as one image. 
     
     
         21 . An imaging system as recited in  claim 1 , wherein said programming is configured to control one or more of actuation timing, intensity, duration and wavelength of the illumination unit. 
     
     
         22 . An imaging system as recited in  claim 1 , wherein said programming is configured to control one or more of focusing, aligning, pre-viewing and final acquisition of the image. 
     
     
         23 . An imaging system as recited in  claim 1 :
 wherein said programming is configured to show a preview of an image of the target to a user; and   wherein the user can evaluate and change location, illumination and focus of the system before a final image is acquired.   
     
     
         24 . An imaging system as recited in  claim 4 , wherein the beam splitter comprises a polarized beam splitter. 
     
     
         25 . An imaging system as recited in  claim 1 , wherein said programming is configured to transform a real inverted image of the target into an image that appears upright to a user viewing the image.