Full-eye illumination ocular surface imaging of an ocular tear film for determining tear film thickness and/or providing ocular topography

• US 8,888,286 B2
• Filed: 12/20/2013
• Issued: 11/18/2014
• Est. Priority Date: 04/01/2009
• Status: Active Grant

• Current Assignee: TearScience Inc. (Johnson & Johnson)
• Original Assignee: TearScience Inc. (Johnson & Johnson)
• Inventors: Grenon, Stephen M., Korb, Donald R.
• Primary Examiner(s): PINKNEY, DAWAYNE
• Application Number:
  US14/137,105
• Publication Number:
  US 20140104574A1
• Time in Patent Office: 333 Days
• Field of Search: 351/206, 351/200, 351/205, 351/209, 351/210, 351221-223, 351/245, 351/246, 351/212, 351/208, 351/160.R, 351/159, 600/247, 600/356, 600/346, 600/476, 600/425
• US Class Current: 351/206
• CPC Class Codes: A61B 3/0025 characterised by electronic signal processing, e.g. eye models
• CPC Class Codes: A61B 3/0058 for multiple images
• CPC Class Codes: A61B 3/1005 for measuring distances inside the eye, e.g. thickness of the cornea A61B3/11 takes precedence
• CPC Class Codes: A61B 3/101 for examining the tear film
• CPC Class Codes: A61B 3/107 for determining the shape or measuring the curvature of the cornea
• 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 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 2207/10144 Varying exposure
• CPC Class Codes: G06T 2207/20224 Image subtraction
• CPC Class Codes: G06T 2207/30041 Eye; Retina; Ophthalmic
• CPC Class Codes: G06T 7/0012 Biomedical image inspection

Abstract

Ocular surface interferometry (OSI) devices, systems, and methods are disclosed for measuring a tear film layer thickness (TFLT) of the ocular tear film, including the lipid layer thickness (LLT) and/or the aqueous layer thickness (ALT). The TFLT can be used to diagnose dry eye syndrome (DES). Certain embodiments also include ocular topography devices, systems and methods for deducing corneal shape by capturing an image of a target reflecting from the surface of the cornea. The image of the target contains topography information that is reviewable by a clinician to diagnose the health of the patient'"'"'s eye by detecting corneal aberrations and/or abnormalities in corneal shape. Certain embodiments also include a combination of the OSI and ocular topography devices, systems and methods to provide imaging that can be used to yield a combined diagnosis of the patient'"'"'s tear film and corneal shape.

Claims

1. An apparatus for imaging an eye, comprising:

a multi-wavelength light source configured to emit light to an eye; and

a control system configured to;

(a) spatially modulate light from the multi-wavelength light source to project a first circular pattern onto the eye, such that at least one first portion of the eye receives emitted light from the multi-wavelength light source and at least one second portion of the eye does not receive the emitted light from the multi-wavelength light source;

(b) receive at an imaging device, at least one first image containing at least one first signal associated with an ocular property of the eye comprising at least one of corneal shape and ocular tear film thickness, comprises the emitted light reflected from the at least one first portion of the eye and at least one background signal;

(c) spatially modulate light from the multi-wavelength light source to project a second circular pattern onto the eye, such that the at least one first portion of the eye does not receive emitted light from the multi-wavelength light source and the at least one second portion on the eye receives the emitted light from the multi-wavelength light source;

(d) receive at the imaging device, at least one second image containing at least one second signal comprising only the at least one background signal; and

(e) subtract the at least one second image from the at least one first image to generate at least one resulting image containing a resultant signal that represents the ocular property of the eye.

2. The apparatus of claim 1, further including a light modulator system communicatively coupled to the control system to spatially modulate light from the multi-wavelength light source to alternately project the first circular pattern and the second circular pattern onto the eye to illuminate the ocular property thereby generating the at least one first signal and the at least one second signal of the ocular property.

3. The apparatus of claim 2, wherein the light modulator system includes a disk disposed between the imaging device and eye for sequentially projecting the first circular pattern and the second circular pattern onto the eye when the disk is illuminated, and wherein the disk includes a central aperture for the imaging device to receive light reflected from the eye.

4. The apparatus of claim 3, wherein the disk is patterned with a plurality of concentric circles having alternating opaque and translucent sections with edges that form radials.

5. The apparatus of claim 4, wherein the light modulator system further includes an electric motor and a drive mechanism for rotating the disk to alternately generate the first circular pattern while the imaging device captures at least one first image containing the at least one first signal of the ocular property and to generate the second circular pattern while the imaging device captures at least one second image containing the at least one second signal of the ocular property.

6. The apparatus of claim 3, wherein the disk is a frusto-conical shaped disk having an open major base that faces the eye and an open minor base that faces the imaging device.

7. The apparatus of claim 3, wherein the disk includes pixels that when illuminated by the multi-wavelength light source projects the first circular pattern in response to a first control signal and projects the second circular pattern in response to a second control signal.

8. The apparatus of claim 1, wherein the multi-wavelength light source is comprised of a multi-wavelength Lambertian light source configured to uniformly or substantially uniformly illuminate the eye.

9. The apparatus of claim 1, wherein the control system is further configured to display at least one of the at least one first image, the at least one second image, or the at least one resulting image on a visual display.

10. The apparatus of claim 9, wherein the control system is further configured to display the at least one resulting image overlaid onto at least one of the at least one first image and the at least one second image on the visual display.

11. The apparatus of claim 1, wherein the ocular property an ocular tear film thickness and the at least one first signal is optical wave interference of specularly reflected light from the ocular tear film combined with the at least one background signal.

12. The apparatus of claim 11, wherein the imaging device is configured to capture the at least one second image when the multi-wavelength light source is not illuminating the at least one second portion of the ocular tear film.

13. The apparatus of claim 11, wherein the imaging device is configured to capture the at least one second image when the multi-wavelength light source is illuminating the at least one second portion of the ocular tear film.

14. The apparatus of claim 11, wherein the control system is configured to receive the at least one first image by being configured to:

capture a first circular tiled pattern of the specularly reflected light including the at least one background signal from the at least a first portion of the ocular tear film in the at least one first image by the imaging device; and

capture a second circular tiled pattern of the specularly reflected light including the at least one background signal from the at least one second portion of the ocular tear film in the at least one second image by the imaging device.

15. The apparatus of claim 14, wherein the control system is configured to receive only the at least one second image containing the at least one background signal from the ocular tear film captured by the imaging device by being configured to:

capture the at least one background signal from the at least one second portion in the first circular tiled pattern in the at least one first image; and

capture the at least one background signal from the at least one first portion of the second circular tiled pattern in the at least one second image.

16. The apparatus of claim 15, wherein the control system is further configured to combine the at least one first image to the at least one second image to form the at least one resulting image in a circular pattern containing the optical wave interference of specularly reflected light from the ocular tear film with the at least one background signal removed or reduced.

17. The apparatus of claim 11, wherein the control system is further configured to:

(f) convert at least a portion of the at least one resulting image representing the optical wave interference of the specularly reflected light from at least a portion of the ocular tear film into at least one color-based value;

(g) compare the at least one color-based value to a tear film layer optical wave interference model; and

(h) measure a tear film layer thickness (TFLT) of the at least a portion of the ocular tear film based on the comparison of the at least one color-based value to the tear film layer optical wave interference model.

18. The apparatus of claim 17, wherein the control system configured to measure the TFLT of the at least a portion of the ocular tear film based on the comparison of the at least one color-based value to the tear film layer optical wave interference model further comprises measuring at least one of a lipid layer thickness (LLT) and an aqueous layer thickness (ALT).

19. The apparatus of claim 11, wherein the at least one first signal and at least one second signal are also associated with the ocular property of the eye comprising corneal shape and ocular tear film thickness.

20. The apparatus of claim 19, wherein the first circular pattern and second circular pattern are generated by spatially modulating light with a disk comprised from the group consisting of a plurality of concentric circles having alternating opaque and translucent sections including edges that form radials.

21. The apparatus of claim 19, wherein the control system is further configured to subtract the at least one second image from the at least one first image to generate at least one resulting image is a Placido pattern that comprises concentric circles and radials.

22. The apparatus of claim 1, wherein the ocular property includes corneal shape and the at least one first signal is associated with at least one first portion of the eye, and the at least one second signal is associated with at least a second portion of the eye.

23. The apparatus of claim 22, wherein the first circular pattern and second circular pattern are generated by spatially modulating light with a disk comprised from the group consisting of a plurality of concentric circles having alternating opaque and translucent sections including edges that form radials.

24. The apparatus of claim 22, wherein the at least one first portion and the at least a second portion are comprised of equal or approximately equal areas.

25. The apparatus of claim 22, wherein the control system is further configured to subtract the at least one second image from the at least one first image to generate at least one resulting image is a Placido pattern that comprises concentric circles and radials.

26. The apparatus of claim 25, wherein the control system is further configured to display the at least one resulting image of the Placido pattern on a visual display.

27. A method for imaging an eye, comprising:

spatially modulating light from a multi-wavelength light source configured to emit light to an eye to project a first circular pattern onto the eye, such that at least one portion of the eye receives emitted light from the multi-wavelength light source and at least one second portion of the eye does not receive the emitted light from the multi-wavelength light source;

receiving at an imaging device, at least one first image containing at least one first signal associated with an ocular property of the eye comprising at least one of corneal shape and ocular tear film thickness, comprises the emitted light reflected from the at least one first portion of the eye and at least one background signal;

spatially modulating light from the multi-wavelength light source to project a second circular pattern onto the eye, such that the at least one first portion of the eye does not receive emitted light from the multi-wavelength light source and the at least one second portion of the eye receives the emitted light from the multi-wavelength light source;

receiving at the imaging device, at least one second image containing at least one second signal comprising only the at least one background signal; and

subtracting the at least one second image from the at least one first image to generate at least one resulting image containing a resultant signal that represents the ocular property of the eye.