Optical system for an ophthamological instrument for examination of pupillary responses

• US 5,042,937 A
• Filed: 12/11/1989
• Issued: 08/27/1991
• Est. Priority Date: 12/11/1989
• Status: Expired due to Term

• Current Assignee: Pulse Medical Instruments Incorporated
• Original Assignee: Pulse Medical Instruments Incorporated
• Inventors: Cornsweet, Tom N.
• Primary Examiner(s): Dzierzynski, Paul M.
• Application Number:
  US07/448,718
• Time in Patent Office: 624 Days
• Field of Search: 351/206, 351/211, 351/214, 351/221, 351/204
• US Class Current: 351/204
• CPC Class Codes: A61B 3/0058 for multiple images
• CPC Class Codes: A61B 3/112 for measuring diameter of pupils
• CPC Class Codes: A61B 3/113 for determining or recording eye movement

Abstract

A pupil function analyzer has three major subsystems; an electro-optical system, an electronic interface system and a computer/software system. The electro-optical system can, in turn, be described in terms of three subsystems; one that delivers controlled lights to the patient'"'"'s eyes, another that forms images of the two pupils on a television camera, and a third that moves the optics to maintain alignment with the patient'"'"'s eyes. The electronic interface system converts signals from the television camera into digital signals to be read by the computer and also responds to the computer to move motors for the maintenance of optical alignment and also operates the light stimuli. The computer/software saves and analyzes the signals sent by the electronic interface, controls the alignment motors, and provides an operator interface, so that the operator can select tests and examine the results.

Claims

1. An ophthalmological instrument for examination of pupillary responses and extrinsic eye muscle balance comprising:

first and second pupil imaging optics, each of said first and second pupil imaging optics including illuminating sources, said first and second pupil imaging optics including

first and second collimating lenses passing collimated images of a patient'"'"'s left and right pupils,

a first mirror located on the optical axis of one of said collimating lenses and at an angle thereto for deflecting a collimated image perpendicular to the optical axis of the other of said collimating lenses,

a first beam splitter located on the optical axis of said other of said collimating lenses and at an angle thereto for passing a collimated image from said other of said collimating lenses and deflecting a collimated image from said one of said collimating means away from and along the axis of said other of said collimating lenses, and

a third lens for focusing the collimated images of a patient'"'"'s left and right pupils on said image plane;

first and second infrared illuminating sources;

first and second light stimulus devices for selectively stimulating the retinas of a patient'"'"'s left and right eyes, said first and second light stimulus devices including

first and second plurality of visible light sources, each of said first and second plurality of light sources corresponding to a plurality of regions of a patient'"'"'s eyes and being individually and selectively energized, and

first and second cold mirrors located on the optical axes of said first and second collimating lenses, respectively, and at an angle thereto to deflect light respectively from said first and second plurality of visible light sources to a patient'"'"'s eyes, said cold mirrors passing infrared light from the patient'"'"'s pupils to said first and second collimating lenses;

second and third beam splitters located on the optical axes of said first and second collimating lenses, respectively, and at an angle thereto to deflect light respectively from said first and second infrared illuminating sources to a patient'"'"'s eyes, said beam splitters passing light from the patient'"'"'s pupils to said first and second collimating lenses; and

a single video camera having a photosensitive image plane, said first and second pupil imaging optics simultaneously focusing images of a patient'"'"'s left and right pupils on different areas of said image plane.

2. The ophthalmological instrument as recited in claim 1 further comprising:

a display screen connected to said video camera and providing a display of a patient'"'"'s left and right pupils as they react to said first and second light stimulus devices, whereby said display screen displays magnified images of the patient'"'"'s left and right pupils closely adjacent one another.

3. The ophthalmological instrument as recited in claim 1 wherein said first and second pupil imaging optics form the images of a patient'"'"'s left and right pupils to that the two images are located close to one another and occupy a large portion of the area of said photosensitive image plane.

4. The ophthalmological instrument as recited in claim 1 further comprising:

first and second fixation light sources, each of said fixation light sources projecting light into a respective one of a patient'"'"'s left and right eyes along optically parallel paths, said first and second fixation light sources appearing to a patient as a single fixation source at infinity.

5. The ophthalmological instrument as recited in claim 1 wherein said first and second pupil imaging optics are relatively movable to allow positioning of said images of a patient'"'"'s left and right pupils on said different areas of said image plane.

6. The ophthalmological instrument as recited in claim 5 wherein said first and second pupil imaging optics are mechanically linked together to compensate for any change in distance to said image plane as said first and second pupil imaging optics are moved relative to one another.

7. The ophthalmological instrument as recited in claim 1 wherein each of said first and second plurality of light sources comprise four light sources corresponding to four quadrants of a patient'"'"'s eyes and said first and second plurality of visible light sources further comprises:

first and second apertures for passing light from respective ones of said four light sources; and

first and second lens assemblies respectively interposed between said first and second apertures and said first and second cold mirrors for imaging light from respective ones of said four light sources on corresponding quadrants of a patient'"'"'s eyes.

8. The ophthalmological instrument as recited in claim 7 further comprising third and fourth visible light sources respectively located in the geometric center of said four light sources comprising each of said first and second visible light sources and appearing to a patient as a single fixation source at infinity.

9. The ophthalmological instrument as recited in claim 8 wherein said first and second lens assemblies each comprise:

four lenses arranged in a common plane to focus images of respective ones of said four light sources on corresponding quadrants of a patient'"'"'s eye; and

a fifth lens located in said common plane and at the geometric center of said four lenses to focus an image of one of said third and fourth visible light sources on said patient'"'"'s eye.

10. The ophthalmological instrument as recited in claim 9 wherein said first and second pupil imaging optics form the images of a patient'"'"'s left and right pupils so that the two images are located close to one another and occupy a large portion of the area of said photosensitive image plane.

11. The ophthalmological instrument as recited in claim 9 wherein said first and second pupil imaging optics are relatively movable to allow positioning of said images of a patient'"'"'s left and right pupils on said different areas of said image plane.

12. The ophthalmological instrument as recited in claim 11 wherein said first mirror is mechanically linked to said other of said collimating lenses to compensate for any change in distance to said image plane as said first and second pupil imaging optics are moved relative to one another.

13. The ophthalmological instrument for examination of pupillary responses and extrinsic eye muscle balance comprising:

illumination means for focusing infrared light in a small spot at a central point of a cornea of one of a patient'"'"'s eyes, said spot being smaller than a pupil of said one of the patient'"'"'s eyes, the infrared light passing through the pupil causing it to be back lighted from light scattered at a retina of said one of the patient'"'"'s eyes; and

measuring means for imaging the back lighted pupil and measuring a diameter of the imaged pupil.

14. The ophthalmological instrument as recited in claim 13 further comprising light stimulus means for focusing visible light on a selected small spot of said cornea, said selected small spot being smaller than said pupil, said visible light illuminating a defined portion of said retina.

15. The ophthalmological instrument as recited in claim 14 further comprising:

second illumination means for focusing infrared light in a small spot at a central point of a cornea of another one of a patient'"'"'s eyes, said spot being smaller than a pupil of said another one of the patient'"'"'s eyes, the infrared light passing through the pupil causing it to be back lighted from light scattered at a retina of said another one of the patient'"'"'s eyes; and

second light stimulus means for focusing visible light on a selected small spot of the cornea of said another one of the patient'"'"'s eyes, said selected small spot being smaller than the pupil of said another one of the patient'"'"'s eyes, said visible light illuminating a defined portion of the retina of said another one of the patient'"'"'s eyes.

16. The ophthalmological instrument as recited in claim 15 wherein said measuring means images both of said pupils on a common photosensitive image plane.