ADAPTIVE INFRARED RETINOSCOPIC DEVICE FOR DETECTING OCULAR ABERRATIONS

• US 20100201944A1
• Filed: 04/19/2010
• Published: 08/12/2010
• Est. Priority Date: 12/20/2005
• Status: Active Grant

• Current Assignee: A&W Healthcare Management, LLC
• Original Assignee: James Waller Lambuth Lewis, Min Wang
• Inventors: Wang, Ming, Lewis, James Waller Lambuth
• Granted Patent: US 8,919,960 B2
• Time in Patent Office: Days
• US Class Current: 351/206
• CPC Class Codes: A61B 3/103 for determining refraction, e.g. refractometers, skiascopes
• CPC Class Codes: A61B 3/14 Arrangements specially adapted for eye photography apparatus or arrangements for taking photographs per se G03B
• CPC Class Codes: G06T 2207/10048 Infrared image
• CPC Class Codes: G06T 2207/20056 Discrete and fast Fourier transform, [DFT, FFT]
• CPC Class Codes: G06T 2207/30041 Eye; Retina; Ophthalmic
• CPC Class Codes: G06T 7/0012 Biomedical image inspection

Abstract

An ocular system for detecting ocular abnormalities and conditions creates photorefractive digital images of a patient'"'"'s retinal reflex. The system includes a computer control system, a two-dimensional array of infrared irradiation sources and a digital infrared image sensor. The amount of light provided by the array of irradiation sources is adjusted by the computer so that ocular signals from the image sensor are within a targeted range. Enhanced, adaptive, photorefraction is used to observe and measure the optical effects of Keratoconus. Multiple near-infrared (NIR) sources are preferably used with the photorefractive configuration to quantitatively characterize the aberrations of the eye. The infrared light is invisible to a patient and makes the procedure more comfortable than current ocular examinations.

Claims

1. A device for detecting high order aberrations in ocular properties of a patient'"'"'s eye, said device comprising:

an array of infrared light sources that produce infrared light;

an image sensor that detects said infrared light and produces an image based upon said detected infrared light wherein said image sensor is positioned such that an axis of an aperture of the image sensor passes through a pupil of said patient'"'"'s eye; and

an optical beam splitter positioned such that said infrared light is redirected from said array of infrared light sources by said optical beam splitter into said patient'"'"'s eye along a path that is coaxial with said axis of said aperture of image sensor, focused to a point on said patient'"'"'s retina by optical elements of said patient'"'"'s eye and reflected and scattered by said patient'"'"'s retina into said image sensor;

wherein said image sensor receives infrared light reflected and scattered from said patient'"'"'s retina and produces an photorefractive image of said patient'"'"'s retinal reflex that is dependent upon any high order aberrations present in said ocular properties of said patient'"'"'s eye;

and wherein said optical beam splitter is adjustable such that eccentrically illuminated photorefractive images of said patient'"'"'s retinal reflex can also be obtained.

2. The device of claim 1 wherein the beam splitter and the array of infrared light sources are positioned such that the distance between the beam splitter and array of infrared light sources is equal to the distance between the beam splitter and an optical entrance pupil of the image sensor.

3. The device of claim 1 further comprising a computer for storing multiple photorefractive images, instantaneously displaying said images for real-time review and digitally analyzing said images to identify ocular abnormalities.

4. The device of claim 1 further comprising a computer that processes said coaxially illuminated image to determine an illumination intensity to use for said array of infrared light sources when producing said eccentrically illuminated image.

5. The device of claim 1 further comprising a computer that selectively activates individual infrared light sources in said array of light sources to automatically produce an array of retinal reflex images corresponding to said array of infrared light sources.

6. A method of providing ocular examination of ocular aberrations that may be present in a patient'"'"'s eye, said method comprising:

producing infrared light with an array of infrared light sources;

directing said infrared light into a pupil of a patient'"'"'s eye with an optical beam splitter such that said infrared light forms a spot on a retina of said patient'"'"'s eye;

detecting infrared light reflected off of said patient'"'"'s retina with a digital camera that can detect infrared light and producing a digital photorefractive image of a retinal reflex of said patient'"'"'s eye based upon said detected infrared light; and

adjusting said optical beam splitter positioned between said digital camera and said patient'"'"'s eye such that said infrared light is directed into said patient'"'"'s eye along a path that is coaxial to an axis of said digital camera and producing a coaxially illuminated photorefractive image of a retinal reflex of said patient'"'"'s eye based upon reflected infrared light detected by said digital camera;

adjusting said optical beam splitter positioned between said digital camera and said patient'"'"'s eye such that said infrared light is directed into said patient'"'"'s eye along a path that is eccentric to said axis of said digital camera and to producing an eccentrically illuminated photo refractive image of a retinal reflex of said patient'"'"'s eye based upon reflected infrared light detected by said digital camera.

7. The method of claim 6 further comprising the step of using said coaxially illuminated photorefractive image to determine an illumination intensity to use for said array of infrared light sources when producing said eccentrically illuminated photorefractive image.

8. The method of claim 6 wherein said digital photorefractive image of said retinal reflex further comprises an ocular wavefront aberration map.

9. The method of claim 6 further comprising the step of automatically adjusting an intensity of said infrared light produced by said array infrared light sources or a sensitivity of said camera based upon a detected retinal reflectance.

10. The method of claim 6 further comprising the step of sequentially lighting selected light sources in said array of infrared lights sources to produce an array of photorefractive retinal reflex images.

11. The method of claim 6 further comprising automatically focusing said camera to acquire photorefractive images from at least one ocular depth other than said patient'"'"'s retina.

12. The method of claim 6 further comprising using a trial lens in front of said patient'"'"'s eye to neutralize ocular defocus.

13. The method of claim 6 further comprising using an ophthalmic condensing lens in front of an examined eye to increase the illumination field angle on a retinal surface to acquire a fundus image in addition to said photorefractive retinal reflex image.

14. The method of claim 6 further comprising subjecting intensity values of pixels in said photorefractive retinal reflex image to Fourier analysis to identify high-order ocular aberrations in said patient'"'"'s eye.

15. The method of claim 6 further comprising performing image correlation analysis between photorefractive retinal reflex images acquired at different times to differentiate between transient and stationary ocular conditions through image correlation analysis.

16. The method of claim 6 further comprising using a temporal or spatial profile of a tear break-up pattern in a sequence of photorefractive retinal reflex images to classify a tear film deficiency.

17. A device for detecting a high order optical aberration, said device comprising:

a two-dimensional array of infrared light sources that produces infrared light from a plurality of predetermined locations;

a digital camera that is positioned to receive infrared light that is reflected from said patient'"'"'s eye and produce a photorefractive digital image of said patient'"'"'s retinal reflex based thereon;

an optical beam splitter for directing infrared light from said two dimensional array of infrared light sources into a patient'"'"'s eye such that the infrared light entering the patient'"'"'s eye from each infrared light source in the two-dimensional array of infrared light sources is focused to a different point on a retina of said patient'"'"'s eye and infrared light from at least one of said infrared light sources is directed into the patient'"'"'s eye by the optical beam splitter so that the infrared light is coaxial with a central axis of the lens of the digital camera and infrared light from at least one other of said infrared light sources is directed into said patient'"'"'s eye by the optical beam splitter so that the infrared light is eccentric to the central axis of the lens of the digital camera; and

a computer that automatically adjusts an intensity of said infrared light produced by said two-dimensional array of infrared light sources or a sensitivity of said digital camera based upon a detected reflectance of said patient'"'"'s retinal reflex.

18. The device of claim 17 wherein said computer automatically adjusts the intensity of said infrared light produced by said two dimensional array of infrared light sources for eccentrically illuminated photorefractive retinal reflex images based upon the intensity level of the detected reflectance when the patient'"'"'s eye is coaxially illuminated with respect to the central axis of the camera lens.

19. The device of claim 17 wherein said computer further comprises software that automatically analyzes said photorefractive retina reflex images to identify high-order ocular aberrations.

20. The device of claim 17 wherein said computer further comprises software that performs image correlation analysis between photorefractive retinal reflex images acquired at different times to differentiate between transient and stationary ocular conditions.