Ophthalmic photothermal optical coherence tomography apparatus

Patent metadata

Field	Value
Publication number	US-10682053-B2
Application number	US-201815940108-A
Country	US
Kind code	B2
Filing date	Mar 29, 2018
Priority date	Mar 29, 2018
Publication date	Jun 16, 2020
Grant date	Jun 16, 2020

Abstract

An optical coherence tomography system for ophthalmic use identifies tissue by selected laser heating of that tissue at reduced power levels decreasing background noise to boost signal-to-noise ratio allowing detection of minute changes in thermal expansion caused by that heating at clinically acceptable levels.

First claim

What we claim is:

1. An ophthalmic retina evaluation system comprising:
an OCT light source;
a photothermal light source providing modulated photothermal light at a predetermined frequency;
a lens system operating to focus combined light from the OCT light source and photothermal light source through a lens of a human eye in vivo on a human retina and to return a reflected signal;
an optical system dividing the reflected signal into reflection components each associated with a depth in the retina; and
an electronic computer communicating with the optical system to receive values of the reflection components executing a stored program to:
(1) analyze changes in apparent depths of the reflection components as a function of modulation of the modulated photothermal light to identify heating of retinal tissue of the human eye as a function of apparent depth range; and
(2) output information isolating the retinal tissue at a depth range having a predetermined threshold heating;
wherein the modulated photothermal light measured at an output of the lens system incident to a position of the human eye has an average power of less than 1 mw over a 0.7 mm diameter aperture.

2. The ophthalmic retina evaluation system of claim 1 wherein light from the OCT light source combined with the light from the modulated photothermal light source measured at an output of the lens system incident to a position of the human eye has an average power of less than 1 mw over a 0.7 mm diameter aperture.

3. The ophthalmic retina evaluation system of claim 1 wherein the photothermal light source projects the light on the retina for a duration of less than 100 ms during a 5 second interval.

4. The ophthalmic retina evaluation system of claim 1 wherein the modulated photothermal light has a frequency greater than 100 hertz with an on-duty cycle of less than 60 percent.

5. The ophthalmic retina evaluation system of claim 1 wherein the output information is a depth image of the retina including the isolated retinal tissue at a depth range within the retina.

6. The ophthalmic retina evaluation system of claim 1 wherein the output information is a quantitative volumetric measurement of isolated retinal tissue within a predetermined area.

7. The ophthalmic retina evaluation system of claim 6 further including a camera providing an image of the retina and wherein the electronic computer stores at least one retina template image having a marked region to correlate the retina template image with the image of the retina to locate the predetermined region.

8. The ophthalmic retina evaluation system of claim 1 wherein the output is a quantitative measurement of pigment concentration.

9. The ophthalmic retina evaluation system of claim 1 wherein the photothermal light source provides light centered on a peak frequency of absorption of indocyanine green (ICG).

10. The ophthalmic retina evaluation system of claim 1 wherein the photothermal light provides light centered on a peak frequency of absorption of fluorescein.

11. The ophthalmic retina evaluation system of claim 1 wherein the photothermal light provides light matching a frequency of absorption of melanin.

12. The ophthalmic retina evaluation system of claim 1 wherein the optical system is at least one of an interferometer and spectrometer.

13. A method of analyzing a human eye employing an ophthalmic retina evaluation system having:
an OCT light source;
a photothermal light source providing modulated photothermal light at a predetermined frequency;
a lens system operating to focus combined light from the OCT light source and photothermal light source through a lens of a human eye in vivo on a human retina and to capture a reflected signal;
an optical system dividing the reflected signal into reflection components each associated with a depth in the retina; and
an electronic computer receiving values of the reflection components and executing a stored program to:
(1) analyze changes in apparent depths of the reflection components as a function of modulation of the modulated photothermal light to identify heating of retinal tissue of a human eye as a function of apparent depth range; and
(2) output information isolating the retinal tissue at a depth range having a predetermined threshold heating;
the method comprising the steps of:
(a) administering a contrast material to a patient for selective accumulation in a layer of the retina; and
(b) employing the ophthalmic retina evaluation system to provide output information isolating the retinal tissue accumulating the contrast material;
wherein the contrast material has a concentration of less than one milligram per milliliter as administered.

14. The method of claim 13 wherein the contrast material is selected from the group consisting of indocyanine green and fluorescein.

15. The method of claim 13 wherein the modulated photothermal light measured at an output of the lens system incident to a position of the human eye has an average power of less than 1 mw over a 0.7 mm diameter aperture.

16. The method of claim 13 wherein light from the OCT light source combined with light from the photothermal light source measured at an output of the lens system incident to a position of the human eye has an average power of less than 1 mw over a 0.7 mm diameter aperture.

17. The method of claim 13 wherein the photothermal light source projects the light on the retina for a duration of less than 100 ms during a 5 second interval.

18. The method of claim 13 wherein the modulated photothermal light has a frequency greater than 100 hertz with an on-duty cycle of less than 60 percent.

19. The ophthalmic retina evaluation system of claim 1 wherein the output is a chart showing change in at least one of volume of the isolated retinal tissue and concentration of pigment over time.

Assignees

• Wisconsin Alumni Res Found
• Wisonsin Alumni Res Foundation
• Univ Vanderbilt

Inventors

• Lapierre-Landry Maryse
• Skala Melissa
• Tao Yuankai

Classifications

• A61B3/102 Primary

  for optical coherence tomography [OCT] · CPC title

• A61B3/1225

  using coherent radiation · CPC title

• G01B9/02091

  Tomographic interferometers, e.g. based on optical coherence · CPC title

• A61B3/12

  for looking at the eye fundus, e.g. ophthalmoscopes (A61B3/13 takes precedence) · CPC title

• G01B21/085

  using thermal means · CPC title