Ophthalmic device

Patent metadata

Field	Value
Publication number	US-12569137-B2
Application number	US-202318202170-A
Country	US
Kind code	B2
Filing date	May 25, 2023
Priority date	May 27, 2022
Publication date	Mar 10, 2026
Grant date	Mar 10, 2026

Abstract

An ophthalmic device that may include: a light source; a measurement optical system that generates measurement light; a first reference optical system that generates first reference light; a second reference optical system that generates second reference light; and an interference optical system that generates measurement interference light from the measurement light and the first reference light, and reference interference light from the first and second reference light. The measurement optical system may include a switching unit that switches between a first state in which the subject eye is irradiated with the light from the light source and a second state in which the light from the light source is guided to the second reference optical system branching from the measurement optical system. The controller may control the switching unit to detect the measurement interference light in the first state, and the reference interference light in the second state.

First claim

What is claimed is:

1 . An ophthalmic device comprising:
a light source; a measurement optical system configured to generate measurement light by irradiating a subject eye with light from the light source; a first reference optical system configured to generate first reference light by using the light from the light source; a second reference optical system configured to generate second reference light by using the light from the light source, the second reference light being used for calculating a reference position; an interference optical system configured to generate measurement interference light by combining the measurement light and the first reference light and to generate reference interference light by combining the second reference light and the first reference light; a detector configured to detect the measurement interference light and output a measurement interference signal and to detect the reference interference light and output a reference interference signal; and a controller configured to calculate depthwise position information of the subject eye based on the measurement interference signal and to calculate the reference position based on the reference interference signal, wherein the second reference optical system includes an optical path branching from the measurement optical system, the measurement optical system comprises a switching unit configured to switch between a first state and a second state, the first state being a state in which the subject eye is irradiated with the light from the light source and the second state being a state in which the light from the light source is guided to the second reference optical system, when the subject eye is measured, the controller is configured to control the switching unit to detect the measurement interference light with the detector in the first state, and to detect the reference interference light with the detector in the second state, and 0 wherein the ophthalmic device further comprises a storage unit configured to store a specific-time reference position indicating the reference position adjusted at a specific time, the specific-time reference position being a position calculated from the reference interference light generated by combining the second reference light generated in the second reference optical system and the first reference light generated in the first reference optical system at the specific time, and the controller is configured to correct the depthwise position information of the subject eye calculated based on the measurement interference signal outputted from the detector when the subject eve is measured, the depthwise position information being corrected based on a difference between a measurement-time reference position and the specific-time reference position stored in the storage unit, the measurement-time reference position being the reference position calculated based on the reference interference signal outputted from the detector when the subject eve is measured.

2 . The ophthalmic device according to claim 1 , wherein
the controller is configured to control the switching unit to detect the reference interference signal with the detector in the second state before or after detecting the measurement interference light with the detector in the first state.

3 . The ophthalmic device according to claim 1 , wherein
the storage unit is configured to further store a conversion formula for converting the depthwise position information of the subject eye calculated based on the measurement interference signal to an actual measurement of the subject eye, the controller is configured to further calculate the actual measurement of the subject eye by converting the depthwise position information of the subject eye calculated based on the measurement interference signal with the conversion formula, and the conversion formula is obtained by using (A) depthwise position information of at least two reflection surfaces of a calibration tool having a known optical path length difference and (B) the optical path length difference between the at least two reflection surfaces, the depthwise position information of the at least two reflection surfaces being obtained from calibration interference light generated by combining calibration measurement light and the first reference light generated in the first reference optical system, the calibration measurement light being generated by irradiating the calibration tool from the measurement optical system with the light from the light source.

4 . The ophthalmic device according to claim 3 , wherein
the specific time and a time at which the calibration interference light is measured by using the calibration tool to obtain the conversion formula are substantially simultaneous.

5 . An ophthalmic device comprising;
a light source; a measurement optical system configured to generate measurement light by irradiating a subject eye with light from the light source; a first reference optical system configured to generate first reference light by using the light from the light source; a second reference optical system configured to generate second reference light bv using the light from the light source, the second reference light being used for calculating a reference position; an interference optical system configured to generate measurement interference light by combining the measurement light and the first reference light and to generate reference interference light by combining the second reference light and the first reference light, a detector configured to detect the measurement interference light and output a measurement interference signal and to detect the reference interference light and output a reference interference signal, and a controller configured to calculate depthwise position information of the subject eye based on the measurement interference signal and to calculate the reference position based on the reference interference signal, wherein the second reference optical system includes an optical path branching from the measurement optical system, the measurement optical system comprises a switching unit configured to switch between a first state and a second state, the first state being a state in which the subject eve is irradiated with the light from the light source and the second state being a state in which the light from the light source is guided to the second reference optical system, when the subject eve is measured, the controller is configured to control the switching unit to defect the measurement interference light with the detector in the first state, and to detect the reference interference light with the detector in the second state, and wherein the ophthalmic device further comprises a storage unit configured to store a specific-time reference position indicating the reference position adjusted at a specific time, the specific-time reference position being a position calculated from the reference interference light generated by combining the second reference light generated in the second reference optical system and the first reference light generated in the first reference optical system at the specific time, wherein the first reference optical system comprises an adjuster configured to adjust an optical path length of the first reference light, and the controller is configured to calculate a measurement-time reference position that is the reference position calculated based on the reference interference signal outputted from the detector when the subject eye is measured and to control the adjuster so that the measurement-time reference position calculated when the subject eye is measured matches the specific-time reference position stored in the storage unit.

6 . The ophthalmic device acco

Assignees

• Tomey Corp

Inventors

• Yamanari Masahiro
• Okamoto Keiichiro

Classifications

• G01B9/02091

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

• 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

• A61B3/0025

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

• A61B5/0062 Primary

  Arrangements for scanning · CPC title