Method for measuring ocular oxidative metabolism

• US 4,922,919 A
• Filed: 03/22/1988
• Issued: 05/08/1990
• Est. Priority Date: 03/22/1988
• Status: Expired due to Term

• Current Assignee: Duke University
• Original Assignee: Duke University
• Inventors: Novack, Roger L.
• Primary Examiner(s): Howell, Kyle L.
• Assistant Examiner(s): Hanley, John C.
• Application Number:
  US07/171,831
• Time in Patent Office: 777 Days
• Field of Search: 128/632-634, 128/664-666, 128/745
• US Class Current: 600/320
• CPC Class Codes: A61B 3/10 Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions

Abstract

A method of measuring the oxidative metabolism of ocular tissue. The ocular tissue is alternately illuminated, with light of a sample wavelength corresponding to the absorption peak of cytochrome a,a₃ and light of a reference slightly above or below the sample wavelength. Light reflected by the ocular tissue is detected and an electronic signal corresponding to said light produced. The signal corresponding to the reference wavelength is subtracted from the produced signal. In a preferred embodiment an optical probe with a first probe to deliver light to the ocular tissue and a second probe to deliver reflected light to a detector is provided. The optical probe is placed on the ocular tissue under study.

Claims

1. A method to detect oxidative metabolism of ocular tissue comprising the steps of:

bleaching photopigments in said ocular tissue with a bright flash;

generating a first beam of optical energy of a predetermined reference wavelength;

generating a second beam of optical energy of a predetermined sample wavelength;

alternately illuminating said ocular tissue with said first beam and said second beam;

detecting optical energy reflected by said ocular tissue;

converting said optical energy to a first electronic signal;

subtracting a second electronic signal from said first electronic signal to obtain a third electronic signal; and

processing said third electronic signal to determine said oxidative metabolism.

2. A method as in claim 1 wherein said illuminating step includes transmitting said first and second beam through a first optical fiber.

3. A method as in claim 2 wherein said detecting means comprises the step of transmitting said reflected light through a second optical fiber to a detector.

4. A method as in claim 3 further comprising the step of placing said first and second optical fiber on said ocular tissue.

5. A method as in claim 4 further comprising the steps of converting said detected optical energy to an electronic signal comprised of a signal corresponding to said reference wavelength and a signal corresponding to said sample wavelength and subtracting the signal corresponding to said reference wavelength from said electronic signal associated with said sample wavelength.

6. A method of measuring the presence of cytochrome a, a₃ in ocular tissue comprising the steps of:

bleaching photopigments in said ocular tissue with a bright flash;

generating a source beam of light of a predetermined intensity;

dividing and filtering said source beam into a first component of a first predetermined wavelength and a second component of a second predetermined wavelength;

alternately transmitting said first and second components to a first optical fiber;

transmitting light reflected from said ocular tissue to a photomultiplier tube;

converting said reflected light to an electronic signal;

subtracting a signal associated with said first wavelength from a signal associated with said second wavelength;

processing said signal associated with said second wavelength to determine the concentration of said cytochrome a, a₃.

7. A method as in claim 6 further comprising the step of adjusting the intensity of said beam so that said beam reaches the posterior of the eye.

8. A method of measuring the oxygen metabolism of ocular tissue comprising the steps of:

bleaching photopigments in the ocular tissue with a bright flash;

placing a contact lens on the cornea of the eye;

generating a first beam of light at a first predetermined wavelength;

generating a second beam of light at a second predetermined wavelength;

transmitting said first and second beam of light through said contact lens to ocular tissue;

detecting the light reflected by said ocular tissue;

converting said reflected light to an electronic signal;

subtracting an electronic signal associated with said first wavelength from the electronic signal associated with said second wavelength thereby forming a resultant electronic signal; and

processing said resultant electronic signal to determine the oxygen metabolism of the ocular tissue.

9. A method as in claim 8 further comprising the steps of converting said reflected light to an electronic signal and subtracting a signal associated with said first predetermined wavelength from said electronic signal.

10. A method as in claim 9 further comprising the step of transmitting a bright flash through said contact lens to said ocular tissue prior to said first generating step.

11. A method as in claim 10 further comprising the step of correcting said reflected signal for a melanin component.

12. A method of detecting optic nerve and retinal metabolism comprising the steps of:

bleaching photopigments in said ocular tissue;

generating a source light beam;

splitting said source beam into a first component and a second component;

filtering said first component to exclude all wavelengths except a predetermined first wavelength;

filtering said second component to exclude all wavelengths except a predetermined second wavelength;

placing an optic probe having a first optical fiber and a second optical fiber therein near the optic nerve;

transmitting said first component and said second component alternatively through said first optical fiber;

transmitting light reflected by said optic nerve through the second optical fiber to a detector; and

converting said reflected light to a first electronic signal; and

subtracting a second electronic signal from said first electronic signal to obtain a third electronic signal;

processing said third electronic signal to obtain said ocular metabolism.

13. A method as in claim 12 further comprising the step of subtracting a signal associated with said first predetermined wavelength from a signal associated with said second predetermined wavelength.

14. A method as in claim 13 further comprising the step of passing a bright flash of light through said first optical fiber prior to alternatively transmitting said first and second components.