US-20260123832-A1 - SYSTEM FOR A FULL-FIELD OCT EYE MEASUREMENT

US20260123832A1US 20260123832 A1US20260123832 A1US 20260123832A1US-20260123832-A1

Abstract

A system for a full-field OCT eye measurement, comprising:—a source ( 1 ) of a light beam (2),—a detector ( 3 ), preferably in form of a camera,—an interferometer, comprising a reference arm ( 4 ) and a sample arm (5),—a beam splitter ( 6 ), configured to receive the light beam ( 2 ) and to split the light beam ( 2 ) into a sample beam ( 7 ) and a reference beam ( 8 ) and further configured to direct the sample beam ( 2 ) to the sample arm ( 5 ) and the reference beam ( 8 ) to the reference arm ( 4 ) respectively, wherein the sample arm ( 5 ) is configured for guiding the sample beam ( 7 ) through a point on the cornea of a subject's eye ( 9 ) into the subject's eye ( 9 ) and back to the detector through the beam splitter ( 6 ), wherein the reference arm ( 4 ) is configured for guiding the reference beam ( 8 ) to a mirror ( 10 ) and back to the detector ( 3 ) through the beam splitter ( 6 ), wherein said detector ( 3 ) is configured and programmed for comparing the sample beam ( 7 ) and the reference beam ( 8 ) for detecting diseases of the subject's eye ( 9 ). The system is characterized in that it comprises an arrangement for decreasing the intensity of the sample beam ( 7 ) passing through the point of the cornea of the subject's eye ( 9 ).

Inventors

Maciej Daniel WOJTKOWSKI

Assignees

INCELLVU S.A.

Dates

Publication Date: 20260507
Application Date: 20231002
Priority Date: 20221005

Claims (10)

1 . A system for a full-field OCT eye measurement, comprising: a source of a light beam, a detector, preferably in form of a camera, an interferometer, comprising a reference arm and a sample arm, a beam splitter, configured to receive the light beam and to split the light beam into a sample beam and a reference beam and further configured to direct the sample beam to the sample arm and the reference beam to the reference arm respectively, wherein the sample arm is configured for guiding the sample beam through a point on the cornea of a subject's eye into the subject's eye and back to the detector through the beam splitter, wherein the reference arm is configured for guiding the reference beam to a mirror and back to the detector through the beam splitter, wherein said detector is configured and programmed for comparing the sample beam and the reference beam for detecting diseases of the subject's eye, characterised in that it comprises an arrangement for decreasing the intensity of the sample beam passing through the point of the cornea of the subject's eye, wherein the sample beam is configured to be focused in front of the subject's eye, wherein the arrangement comprises means for moving the sample beam parallel to its original direction so as to change the point of the cornea through which the sample beam enters the subject's eye, and wherein said means for moving are configured for moving the source of the light beam.
2 . (canceled)
3 . (canceled)
4 . The system according to claim 1 , characterised in that said means for moving comprises a movable lens that is placed between the beam splitter and the subject's eye.
5 . The system according to claim 1 , characterised in that the arrangement comprises means for dithering the sample beam.
6 . The system according to claim 5 , characterised in that said means for dithering are configured for temporarily switching on and off the source of the light.
7 . The system according to claim 5 , characterised in that said means for dithering comprises a movable diaphragm or movable mirror placed between the beam splitter and the subject's eye or between the source of the light beam and the beam splitter.
8 . The system according to claim 1 , characterised in that the arrangement comprises means for splitting the sample beam into at least two separate sample sub-beams and for directing the at least two sample sub-beams into the subject's eye through at least two different points on the cornea of the subject's eye, wherein said means for splitting are placed between the beam splitter and the subject's eye.
9 . The system according to claim 1 , characterised in that it comprises limiting means configured for limiting the position of the focus of the sample beam with respect to the cornea of the subject's eye such that the distance between the focus of the sample beam and the cornea of the subject's eye is not smaller than a predefined minimal distance.
10 . The system according to claim 9 , characterised in that the limiting means comprises a camera.

Description

TECHNICAL FIELD The present invention relates to full-field OCT (optical coherence tomography) eye measurement, in particular to system for a full-field OCT eye measurement, especially with laser light, which raises safety concerns, specifically in the imaging techniques from the full-field family. BACKGROUND In the full-field modalities the eye illuminating beam is being focused in front of the patient's eye so it can be naturally collimated by the patient's eye lens to uniformly cover the retina. The natural focal length of the human eye lens is close to the eyeball internal length which equals approximately 20 mm. The eye lens focuses the incoming collimated beam onto the retina. However, in the full-field retina imaging methods the situation is inverted and it is desired to obtain a uniform illumination of the retina by collimating the beam on it. To achieve this, a focus is formed in front of the eye in the focal distance from the lens which is similar to that between the lens and the retina. Such proximity of the beam with respect to the front of the eye poses a threat of exceeding the laser safety norms for the light intensity allowed on the cornea and causing consequent damage. This danger may become unnoticed by the operators and the system designers due to the fact of the retina being the imaging object while the cornea and the lens are only used as transmissive optics. Especially during the initial instrument alignment when the focus position gets shifted in the search of optimal image quality, the focus is likely to approach the cornea to the distance too close for the power density to be still compliant with the safety norms. Document U.S. Pat. No. 10,758,123B2 discloses an ophthalmological microscope system, having an illumination system that projects illumination light onto a subject's eye. A light receiving system guides returning light of the illumination light to an image sensor or an eyepiece system. An interference optical system splits light into measurement light and reference light and detects interference light generated from returning light of the measurement light and the reference light. A designation unit is used for designating an operation mode. When an observation priority mode (or an OCT priority mode) has been designated, a controller executes first light amount control that restricts light amount of the measurement light (or second light amount control that restricts light amount of the illumination light) to make total light amount of the illumination light and the measurement light equal to or less than a predetermined value. This solution says nothing about the position of the light beam on the eye. In particular, it is silent about any way of protecting the eye. Document U.S. Pat. No. 7,061,622B2 describes an optical coherence tomography (OCT) system including an interferometer that provides illuminating light along a first optical path to a sample and an optical delay line and collects light from the sample along a second optical path remitted at several scattering angles to a detector. In one embodiment, illuminating light is directed along a number of incident light paths through a focusing lens to a sample. The light paths and focusing lens are related to the sample and to both the incident light source and the detector. In another embodiment, a focusing system directs light to a location in the sample. A transmission grating or acousto-optic modulator directs light from the sample at an angle representative of the wavelength of the incident light on the transmission grating or acousto-optic modulator. This solution does not solve the problem of too high intensity of the light beam falling on a fixed point on the cornea. Document CN114903425A discloses the invention that provides a visible light OCT (Optical Coherence Tomography) device and method for reducing eye watching fatigue during focusing. A first light source is connected with an optical coupler through an optical fiber, the optical coupler is connected with the input end of a first collimator through an optical fiber, the optical coupler is connected with a spectrograph through an optical fiber, and the spectrograph is communicated with a processing terminal. The first scanning galvanometer is used for scanning output light of the first collimator in a first direction, and the second scanning galvanometer is used for scanning reflected light of the first scanning galvanometer in a second direction to obtain first reflected light; the second light source is connected with the input end of the second collimator through an optical fiber, the third scanning galvanometer is used for scanning output light of the second collimator in the first direction, and the second scanning galvanometer is used for scanning reflected light of the third scanning galvanometer in the second direction to obtain second reflected light; the first focusing lens and the second focusing lens form a 4f system, and the 4f system is used