Low cost fundus imager with integrated pupil camera for alignment aid

Patent metadata

Field	Value
Publication number	US-12029486-B2
Application number	US-201917277177-A
Country	US
Kind code	B2
Filing date	Sep 24, 2019
Priority date	Sep 28, 2018
Publication date	Jul 9, 2024
Grant date	Jul 9, 2024

Abstract

A low cost fundus camera uses LED light sources placed adjacent the camera's imaging stop, and thereby eliminates the need for optics for introducing the light source to the camera's optical path. Lens reflex in the pupil relay is avoided by using only reflective optics in the pupil relay. Reflex from the LED is mitigated by actuating each LED separately, one at a time, and capturing a separate image with each actuated LED. Reflex-free regions of each captured image are extracted and combined to create a composite reflex-free image.

First claim

The invention claimed is:

1. An ophthalmic diagnostic system for imaging an eye, comprising:
a detector configured for capturing an image of the eye, the detector having a detector aperture;
at least a first light source and a second light source proximate to the detector aperture; and
one or more data processors;
wherein:
the detector configured to capture a first image of the eye with the first light source actuated and the second light source not actuated, and configured to capture a second image of the eye with the second light source actuated and the first light source not actuated and configured to generate output signals in response thereto; and
the one or more data processors are configured to use the output signals to extract a first section of the first image excluding reflex artifacts from the first light source, extract a second section of the second image excluding reflex artifacts from the second light source, and combine the first and second sections to construct a composite image.

2. The ophthalmic diagnostic system of claim 1 , further comprising at least a third light source, wherein:
the first light source and the second light source are configured to illuminate the retina of the eye and the third light source is configured to illuminate the pupil of the eye; and
the detector has a first imaging region conjugate to the retina of the eye and a second imaging region conjugate to the pupil of the eye.

3. The ophthalmic diagnostic system of claim 2 , wherein the third light source is an infrared light source and the first light source and the second light source are visible light sources.

4. The ophthalmic diagnostic system of claim 2 , wherein the detector includes a first photo-detector array in front of a second photo-detector array along an axial optical path of the detector, the first imaging region being within the first photo-detector array, and the second imaging region being within the second photo-detector array.

5. The ophthalmic diagnostic system of claim 4 , further comprising:
a detector lens having an outer region surrounding a central aperture along the axial optical path of the detector, the diameter of the aperture being large enough to prevent the detector lens from receiving reflected light from the retina of the eye, the outer region configured to focus reflected light from the pupil of the eye to the second imaging region of the second photo-detector array.

6. The ophthalmic diagnostic system of claim 5 , wherein:
the first photo-detector array is part of a first camera unit;
the second photo-detector array is part of a second camera unit; and
the first camera unit is inserted within the central aperture.

7. The ophthalmic diagnostic system of claim 2 , wherein the first imaging region and second imaging region are defined within a single photo-detector array.

8. The ophthalmic diagnostic system of claim 1 , further comprising a curved reflector surrounding the detector and directed towards the eye, the reflector configured to provide an image of the eye viewable by the patient, wherein the image of the eye viewable by the patient is indicative of an alignment of the detector with the eye.

9. The ophthalmic diagnostic system of claim 1 , further comprising a first curved reflector separated from a second curved reflector in an optic path from the detector aperture and to the eye, with no system lens within the optic path.

10. The ophthalmic diagnostic system of claim 9 , wherein:
the first curved reflector configured to receive light from the first light source and the second light source are configured to at a first field-of-view (FOV), and configured to reflect the received light to the second curved reflector; and
the second curved reflector configured to reflect the received light from the first reflector to the eye at a second FOV different than the first FOV.

11. The ophthalmic diagnostic system of claim 10 , wherein the second FOV is greater than the first FOV.

12. The ophthalmic diagnostic system of claim 9 , wherein the separation between the first curved reflector and the second curved reflector is configured to be adjusted to compensate for a refractive error in the eye.

13. The ophthalmic diagnostic system of claim 1 , wherein:
the captured first image includes the upper hemisphere and lower hemisphere of the eye; and
the captured second image includes the upper hemisphere and lower hemisphere of the eye.

14. The ophthalmic diagnostic system of claim 1 , wherein:
the extracted first section includes the entirety of an upper hemisphere or a lower hemisphere of the imaged eye; and
the extracted second section includes the entirety of the other of the upper hemisphere or the lower hemisphere of the imaged eye.

15. The ophthalmic diagnostic system of claim 1 , wherein the excluded reflex artifacts from the first light source and the second light source includes corneal reflex and lacks system lens artifacts.

16. The ophthalmic diagnostic system of claim 1 , wherein:
the first light source and the second light source are adjacent to the detector aperture; and
the first light source, the second light source, and the detector share the same optics for illumination and detection.

17. An ophthalmic diagnostic system for imaging an eye of a patient, comprising:
a detector configured for capturing an image of the eye, the detector having a detector aperture;
at least one light source proximate to the detector aperture; and
a curved reflector at least partially surrounding the detector and directed towards the eye, the reflector configured to provide an image of the eye viewable by the patient;
wherein the image of the eye viewable by the patient is indicative of an alignment of the detector to the eye, and is configured to be usable by the patient to self-align the detector to the eye's iris.

18. The ophthalmic diagnostic system of claim 17 , wherein:
the curved reflector is behind the detector and on an optical axis of the detector; and
the image of the eye viewable by the patient includes an image of the eye's pupil with a shadow region corresponding to a position of the detector, and the detector is configured to be aligned to the eye's iris by aligning the shadow region to a central region of the image of the eye's pupil.

19. The ophthalmic diagnostic system of claim 17 , further comprising:
a user-input configured to control movement of the detector within at least one plane of motion;
wherein the user uses the user-input to self-align the detector to the iris.

20. The ophthalmic diagnostic system of claim 17 , further comprising at least one second curved reflector in an optic path between the detector aperture and the eye, with no system lens within the optic path.

21. The ophthalmic diagnostic system of claim 17 , wherein the least one light source includes at least one infrared light source and one visible light source.

Assignees

• Zeiss Carl Meditec Inc
• Zeiss Carl Meditec Ag

Inventors

• Straub Jochen
• Sprowl Robert
• Liu Yuan
• Everett Matthew J

Classifications

• A61B3/14

  Arrangements specially adapted for eye photography · CPC title

• A61B3/0025

  characterised by electronic signal processing, e.g. eye models · CPC title

• A61B3/158

  of corneal reflection · CPC title

• A61B3/0033

  characterised by user input arrangements · CPC title

• A61B3/0008

  provided with illuminating means (A61B3/117, A61B3/14 take precedence) · CPC title