Hand held device and methods for examining a patient's retina

Abstract

A hand held device for examining a patient's retina. In one example, the device generates visible or non-visible illuminating beams having desired spectral content. The illuminating beams are then polarized to generate polarized light beam(s) that are directed towards the patient's retina. At the patient's eye, a portion of the polarized beam is partially reflected by the cornea and travels back to the device, and another portion of the polarized beam enters the eye through the undilated pupil, illuminates the patient's retina, and generates a reflected retinal image (generally de-polarized) which also travels back to the device. The device receives the retinal image and transmits certain portions of the retinal image on through to an image detector (i.e., CCD or CMOS); and the device deflects the received polarized corneal reflections away from the image capture device. Hence, the image capture device receives retinal images but does not receive the polarized corneal reflected light.

1 . A hand held device for examining a retina through a pupil, comprising: 
 a light source generating light;    a first lens refracting the light to form a refracted beam;    a first polarizer receiving the refracted beam and forming a linear polarized beam;    a second polarizer for reflecting linearly polarized light, the second polarizer receiving the linear polarized beam and reflecting the linear polarized beam; and]   a second lens refracting the linear polarized beam from the second polarizer, the second lens converging the linear polarized beam for passage through the pupil to illuminate the retina and create a reflection comprising linear polarized light reflected from a cornea and depolarized light reflected from the retina; and    wherein the second polarizer is oriented such that it reflects the linear polarized light reflected from the cornea and passes at least a portion of the depolarized light reflected from the retina.    
     
     
         2 . The hand held device of  claim 1 , wherein the light generated by the light source includes infrared (IR) light.  
     
     
         3 . The hand held device of  claim 1 , wherein the light source includes a first lamp in series with an infrared (IR) filter to generate the light.  
     
     
         4 . The hand held device of  claim 1 , wherein the light generated by the light source includes visible light.  
     
     
         5 . The hand held device of  claim 1 , further comprising: a reflector reflecting the light to form a reflected converging beam for coupling into the first lens.  
     
     
         6 . The hand held device of  claim 1 , further comprising: a variable diaphragm located between the light source and the first lens for controlling the intensity of the light.  
     
     
         7 . The hand held device of  claim 1 , further comprising: a beam splitter positioned between the first lens and the first polarizer, the beam splitter receiving the refracted beam, the beam splitter reflecting the refracted beam to the first polarizer.  
     
     
         8 . The hand held device of  claim 1 , wherein the first polarizer is a wire grid polarizer.  
     
     
         9 . The hand held device of  claim 1 , wherein the second polarizer is a wire grid polarizer, the second polarizer is substantially disposed at an angle of 45 degrees relative to linear polarized beam.  
     
     
         10 . The hand held device of  claim 1 , wherein the pupil is undilated during examination of the retina.  
     
     
         11 . A hand held device for examining a retina through a cornea and a pupil, comprising: 
 a light source generating light;    a reflector reflecting the light to form a reflected beam;    a polarizer receiving the reflected converging beam and forming a linear polarized beam;    a second polarizer for reflecting linearly polarized light, the second polarizer receiving the linear polarized beam and reflecting the linear polarized beam for passage through the pupil to illuminate the retina and create a reflection therefrom incident on the second polarizer, the reflection comprising linear polarized light reflected from the cornea and depolarized light reflected from the retina;    wherein the second polarizer is oriented to reflect the linear polarized light reflected from the cornea and passes at least a portion of the depolarized light reflected from the retina; and    a camera receiving the portion of depolarized light passed through the second polarizer.    
     
     
         12 . The hand held device of  claim 11 , further comprising: a lens refracting the linear polarized beam from the second polarizer, the lens converging the linear polarized beam for passage through the pupil.  
     
     
         13 . The hand held device of  claim 11 , wherein the light source includes a first lamp in series with an infrared (IR) filter to generate the light, and wherein the light includes IR light.  
     
     
         14 . The hand held device of  claim 11 , wherein the linear polarized converging beam and the linear polarized light reflected from the cornea over the pupil is S-plane linear polarized light.  
     
     
         15 . The hand held device of  claim 11 , wherein the second polarizer further reflects the linear polarized light reflected from the cornea into the light source.  
     
     
         16 . The hand held device of  claim 11 , wherein the second polarizer is a wire grid polarizer, the second polarizer is substantially disposed at an angle of 45 degrees relative to linear polarized beam.  
     
     
         17 . A hand held device for examining a retina through a cornea and a pupil, comprising: 
 a light source generating light;    a reflector reflecting the light to form a reflected beam;    a polarizer receiving the reflected beam and forming a linear polarized beam; and    a second polarizer for reflecting linearly polarized light, the second polarizer receiving the linear polarized beam and reflecting the linear polarized beam through the pupil to illuminate the retina and thereby creating a reflected image of the retina and a linear polarized image of the light source reflected from the cornea, a portion of said reflected image of the retina passing through the second polarizer and said linear polarized image of the light source being reflected by the second polarizer into the first polarizer.    
     
     
         18 . The hand held device of  claim 17 , further comprising: a lens refracting said portion of the reflected image of the retina to create a real image of the retina.  
     
     
         19 . The hand held device of  claim 17 , further comprising: a detector receiving the portion of said reflected image of the retina.  
     
     
         20 . The hand held device of  claim 19 , wherein the detector is a charged coupled device (CCD) detector.  
     
     
         21 . (canceled)