Miniaturized mobile, low cost optical coherence tomography system for home based ophthalmic applications

Patent metadata

Field	Value
Publication number	US-11627874-B2
Application number	US-202117248850-A
Country	US
Kind code	B2
Filing date	Feb 10, 2021
Priority date	Dec 21, 2016
Publication date	Apr 18, 2023
Grant date	Apr 18, 2023

Abstract

Improved optical coherence tomography systems and methods to measure thickness of the retina are presented. The systems may be compact, handheld, provide in-home monitoring, allow the patient to measure himself or herself, and be robust enough to be dropped while still measuring the retina reliably.

First claim

What is claimed is:

1. A compact optical coherence tomography (OCT) system to measure a distance between tissue layers of an eye, the compact OCT system comprising:
a detector;
a light source configured to generate a light beam comprising a plurality of wavelengths;
a plurality of optical elements coupled to the light source to direct the light beam into the eye and generate an interference signal at the detector; and
circuitry coupled to the detector and the light source to determine the distance between tissue layers in response to the interference signal,
wherein the compact OCT system is configured to measure a change in the distance between tissue layers at a precision less than an axial resolution of the compact OCT system, the change in the distance between tissue layers comprising a first thickness at a first time and a second thickness at a second time,
wherein the light source comprises a vertical cavity surface emitting laser (VCSEL) configured to vary an emission wavelength of the light beam over a range from about 5 to 10 nm.

2. The compact OCT system of claim 1 , wherein the change in the distance between tissue layers measured with the compact OCT system is less than the axial resolution of the compact OCT system.

3. The compact OCT system of claim 1 , wherein the axial resolution comprises a resolution value within a range from about 150 μm to about 30 μm.

4. The compact OCT system of claim 1 , wherein the circuitry is configured to vary the emission wavelength with a drive current from the circuitry.

5. The compact OCT system of claim 1 , wherein the distance between tissue layers comprises a distance between a first layer of a retina and a second layer of the retina and the ocular tissue thickness is more than 150 μm.

6. The compact OCT system of claim 1 , wherein the distance between tissue layers is within a range from about 150 to 300 μm, and the axial resolution is within a range from about 150 μm to about 30 μm.

7. The compact OCT system of claim 1 , wherein the distance between tissue layers is measured faster than characteristic frequencies of movement of the compact OCT system in relation to the eye, and wherein the movement is selected from the group consisting of movement related to a patient holding the OCT system in his or her hand, eye movement, and tremor.

8. The compact OCT system of claim 1 , further comprising a viewing target for a patient to align the light beam with a fovea of the eye and wherein the viewing target comprises one or more of the light beam or light from a light emitting diode.

9. The compact OCT system of claim 1 , wherein the VCSEL has a specified maximum rated range of wavelength variation.

10. The compact OCT system of claim 9 , wherein the circuitry is configured to drive the VCSEL beyond the specified maximum range of wavelength variation by at least about 1 nm.

11. The compact OCT system of claim 1 , wherein the circuitry is configured to cause an emitted wavelength to sweep over a range of wavelengths with a sweeping frequency and the circuitry is configured to determine the distance between tissue layers in response to frequencies of the interference signal.

12. The compact OCT system of claim 11 , wherein the sweeping frequency is faster than an ocular tremor of a user, or a hand tremor of the user.

13. The compact OCT system of claim 1 , wherein the circuitry is configured to heat the light source to change the emission wavelength.

14. The compact OCT system of claim 1 , wherein the plurality of optical elements is arranged to provide a reference optical path and a measurement optical path and the interference signal results from interference of light along the reference optical path and the measurement optical path.

15. The compact OCT system of claim 1 , wherein the plurality of optical elements is arranged to provide a measurement optical path and the interference signal results from interference of light from the tissue layers along the measurement optical path.

16. The compact OCT system of claim 1 , wherein the circuitry comprises a processor configured to transform the interference signal into an intensity profile of light reflected along an optical path of the light beam directed into the eye and to determine the distance between tissue layers in response to the intensity profile.

17. The compact OCT system of claim 16 , wherein the intensity profile comprises a plurality of reflected peaks and the processor is configured with instructions to determine the distance between tissue layers in response to the plurality of reflected peaks.

18. The compact OCT system of claim 17 , wherein the processor is configured with instructions to determine the intensity profile in response to frequencies of the interference signal.

19. The compact OCT system of claim 16 , wherein frequencies of the interference signal correspond to separation distances of tissue layers and a rate of change of the wavelength of the light source.

20. The compact OCT system of claim 1 , further comprising a viewing target to align the OCT system with a fovea of the eye and wherein the viewing target comprises one or more of the light beam, a target defined with a light emitting diode, or the VCSEL.

21. The compact OCT system of claim 1 , further comprising housing to support the light source, the optical elements, the detector, and the circuitry, and wherein the housing is configured to be held in a hand of a user in front of the eye in order to direct the light beam into the eye.

22. The compact OCT system of claim 21 , further comprising a sensor to measure which eye is measured in response to an orientation of the housing.

Assignees

• Acucela Inc

Inventors

• Scheibler Lukas
• Pfister Matthias
• Schnell Urban
• Troller Stefan
• Kubota Ryo

Classifications

• A61B3/1005

  for measuring distances inside the eye, e.g. thickness of the cornea (A61B3/11 takes precedence) · CPC title

• A61B3/102 Primary

  for optical coherence tomography [OCT] · CPC title

• G01B9/02

  Interferometers · CPC title

• A61B3/10

  Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions · CPC title

• A61B2505/07

  Home care · CPC title