Segmented focus fast scanning measurement system and method for ocular tissue biometry

Abstract

The application discloses a segmented focusing fast scanning measurement system and method for eye tissue biometry, and belongs to the technical field of eye tissue biometry.The segmented focusing fast scanning measurement system comprises a fast scanning delay line component and a sample arm optical path component.The fast scanning delay line component is used for receiving one light path branched from a light transmission system and returning to the light transmission system after delay, and comprises a fiber collimator, a scanning right-angle mirror, a cylindrical lens, a reflecting mirror and a segmented focusing step mirror.The sample arm optical path component is used for receiving another light path branched from the light transmission system, and the light path is incident to eye tissue through a segmented focusing optical path and is reflected to the light transmission system through the eye tissue, and the sample arm optical path component comprises a fiber output head, a focusing lens and a dichroic mirror.The segmented focusing step mirror is inserted between the fiber output head and the focusing lens.The application realizes synchronous focusing of a detection light beam at an eye anterior segment, a lens and a fundus retina, and further improves a signal-to-noise ratio of a detection signal, so that the whole system is simple in structure and easy to realize.

Description

Technical Field

[0001] This invention belongs to the field of ocular tissue biometry technology, and in particular relates to a segmented focusing rapid scanning measurement system and method for ocular tissue biometry. Background Technology

[0002] Cataracts, one of the most common eye diseases, are prevalent among middle-aged and elderly people. Accurate measurement of axial length is crucial for the precision of intraocular lens implantation during cataract surgery, and also closely relates to postoperative refractive errors.

[0003] Furthermore, the myopia rate among Chinese children and adolescents has remained high in recent years, and the degree of myopia is positively correlated with axial length, which is also an important basis for distinguishing between true and pseudomyopia. Therefore, a high-precision method for measuring axial length is essential, as it has significant practical value for the prevention and clinical diagnosis and treatment of eye diseases.

[0004] Existing methods for measuring axial length mainly include ultrasonic biometry and non-contact optical biometry. Ultrasound offers good accuracy for measuring axial length in normal eyes and is unaffected by the turbidity of the refractive media; however, the method is relatively cumbersome and time-consuming. Non-contact optical biometry utilizes optical coherence techniques to measure axial length, primarily including methods based on partial coherence interferometry (PCI) and methods based on low coherence optical reflectometry (LCOR). Both methods are extensions of Michelson interferometry technology, such as... Figure 1As shown, a weakly coherent light source emits a coherent beam, which is split into two beams by a beam splitter: one called the sample arm and the other the reference arm. The sample arm beam is incident on the object being measured (e.g., eye tissue). Different depths within the object reflect and scatter the incident light, with some reflected light returning to the beam splitter. The reference arm beam is projected onto the surface of a mirror that reciprocates along the optical axis and returns along its original path to the beam splitter, where it converges with the light returning from the sample arm. When the optical path difference between the two reflected beams is equal, an interference fringe corresponding to the measured tissue layer is generated. This interference-informed light is then received by a photodetector after passing through the beam splitter, forming an electrical signal. After sampling and processing, the positional information of different reflection layers within the measured tissue, i.e., the tissue positional information along the axial length of the eye, is obtained. Compared to traditional ultrasonic biometry methods, non-contact optical biometry methods offer advantages such as high resolution and non-contact nature, while also providing better repeatability than ultrasound. However, the accuracy of non-contact optical biometry depends on the intensity of the scanning light reflected from the fundus. Therefore, factors such as turbidity of the refractive media, lesions, or the patient's inability to fixate all affect the accuracy of the measurement data.

[0005] To address detection errors caused by fixation due to involuntary eye movements during measurement, non-contact optical biometry primarily employs methods such as increasing the scanning rate of the interferometer's reference arm optical delay line. This increases the number of repeated scan lines detected per unit time, and the processing of rapidly acquired multiple sets of data improves the signal-to-noise ratio and detection accuracy. Furthermore, to address the signal-to-noise ratio issue caused by the rapid attenuation of detection information due to scattering of the measurement light signal by the eye tissue medium, sample arm zoom technology is mainly used to achieve real-time focusing of tissues at different depths within the axial length of the eye during scanning measurement. However, achieving high signal-to-noise ratio and detection accuracy by simultaneously enabling the interferometer's reference arm to acquire high-speed optical interference information at multiple layers along the axial length of the eye to determine positional information, and simultaneously achieving synchronous focusing of the sample arm's detection beam at different interfaces within the eye tissue, such as the anterior and posterior surfaces of the cornea, the anterior and posterior surfaces of the lens, and the retina, is challenging and results in a complex solution. Summary of the Invention

[0006] The problem to be solved by the present invention is to provide a segmented focusing rapid scanning measurement system and method for ocular tissue biometry, which can realize the high-speed acquisition of optical interference information of multiple layers along the ocular axis by the interferometer reference arm to determine the position information, and simultaneously realize the synchronous focusing of the sample arm detection beam at different interfaces of ocular tissues such as the anterior and posterior surfaces of the cornea, the anterior and posterior surfaces of the lens, and the retina.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a segmented focusing rapid scanning measurement system for ocular tissue biometry, comprising a rapid scanning delay line assembly (reference arm) and a sample arm optical path assembly. The rapid scanning delay line assembly is used to receive one path of light split from the optical transmission system and return it to the optical transmission system after delay. The rapid scanning delay line assembly includes a fiber collimating lens, a scanning right-angle lens for generating optical delay, and a cylindrical lens and a reflecting mirror arranged sequentially along the output light path of the scanning right-angle lens, and a segmented focusing ladder lens for generating a segmented focusing effect in the tested ocular tissue. The sample arm optical path assembly is used to receive another path of light split from the optical transmission system, which is incident on the ocular tissue through the segmented focusing light path and reflected back to the optical transmission system by the ocular tissue. The sample arm optical path assembly includes a fiber optic output head, a focusing lens for generating a focusing effect in the ocular tissue, a dichroic mirror for deflecting and separating light, and a segmented focusing ladder lens for generating a segmented focusing effect in the tested ocular tissue extending between the fiber optic output head and the focusing lens.

[0008] Furthermore, the optical transmission system includes an optical circulator, an optical fiber beam splitter, a first polarization controller, a second polarization controller, and a photodetector for receiving reflected interference light signals, arranged sequentially along the optical axis of a weakly coherent light source (SLD).

[0009] Furthermore, the fast scanning delay line assembly is used to receive one beam of light split from the fiber optic beam splitter and return it to the fiber optic beam splitter after a delay; the sample arm optical path assembly is used to receive another beam of light split from the fiber optic beam splitter, which is incident on the eye tissue via a segmented focusing optical path and reflected back to the fiber optic beam splitter by the eye tissue.

[0010] Furthermore, the multiple scanning right-angle mirrors and the multiple segmented focusing ladder mirrors are respectively fixed on the circumference of the scanning motor, wherein the positions of the scanning right-angle mirrors and the segmented focusing ladder mirrors correspond one-to-one.

[0011] Furthermore, the present invention also includes a control system and a video camera, wherein the control system includes a data acquisition control card and a computer for photoelectric signal conversion and motor control; and the video camera is used to detect video images of the cornea.

[0012] This invention discloses a segmented focusing rapid scanning measurement method for ocular tissue biometry, comprising the following steps:

[0013] S1. The weakly coherent light emitted by the weakly coherent light source (SLD) is incident on port a of the optical circulator, and output to port I of the fiber optic beam splitter via port b of the optical circulator. The fiber optic beam splitter splits the input light into two paths to port III and port IV. The beam output from port III is transmitted to the fiber collimating lens of the fast scanning delay line assembly via the first polarization controller. The collimated incident light is projected onto the scanning right-angle lens used to generate optical delay. The light emitted from the scanning right-angle lens is reflected back to the fiber collimating lens via the cylindrical mirror and the reflecting mirror, and returns to port III of the fiber optic beam splitter via the first polarization controller and converges with the light returning from the sample arm.

[0014] S2. The beam output from the fiber optic beam splitter port IV is sent to the fiber optic output head of the sample arm optical path assembly via the second polarization controller, and then passes through the segmented focusing ladder mirror along the output optical axis. The focusing lens, which generates a focusing effect in the eye tissue, then projects the measurement light onto the eye tissue through the dichroic mirror that deflects and separates the light.

[0015] S3. Different depth layers of the eye tissue reflect and scatter the incident light. One reflected light returns through the original sample arm optical path to the fiber optic beam splitter port IV, where it converges with the light returning from the fast scanning delay line assembly (reference arm). Due to the optical delay generated by the scanning right-angle mirror in the fast scanning delay line assembly (reference arm) rotating with the scanning motor, when the optical path difference between the two reflected light rays reaching the fiber optic beam splitter is equal, an interference bright fringe corresponding to the tissue layer of the sample being tested will be generated. This light ray carrying interference information, after passing through the fiber optic beam splitter port II, together with the light returning through the optical circulator port c, is received by the photodetector to form an electrical signal.

[0016] S4. After sampling and processing by the control system consisting of the acquisition control card and computer, the position information of different reflection layers inside the tested tissue is obtained, that is, the tissue position information in the direction of the axial length.

[0017] This invention designs a high-speed scanning optical delay line device as a reference arm, and integrates the detection optical path, which serves as the sample arm, with the reference arm scanning device through a specially designed segmented focusing ladder lens. This achieves simultaneous adjustment of the detection beam focus by the sample arm through the segmented focusing ladder lens while the reference arm acquires the axial position information at high speed. This enables the detection beam to be simultaneously focused on the anterior segment, lens, and retina, thereby improving the signal-to-noise ratio of the detection signal. The entire system is not only simple in structure but also easy to implement. Attached Figure Description

[0018] The present invention will be described in detail below with reference to the accompanying drawings and examples. The advantages and implementation methods of the present invention will become more apparent from this description. The accompanying drawings are for illustrative purposes only and do not constitute any limitation on the present invention. In the accompanying drawings:

[0019] Figure 1 This is a schematic diagram of the Michelson interferometer principle;

[0020] Figure 2 This is a schematic diagram of the structure of the present invention;

[0021] Figure 3 This is a top view of the fast scanning delay line assembly (reference arm) of the present invention;

[0022] Figure 4 This is a schematic diagram showing the relative positions of the fast scanning delay line scanning right-angle lens and the segmented focusing ladder lens in the fast scanning delay line assembly (reference arm) of the present invention at the anterior segment cornea to form a focus.

[0023] Figure 5 This is a schematic diagram showing the relative positions of the fast scanning delay line scanning right-angle lens and the segmented focusing ladder lens in the lens of the fast scanning delay line assembly (reference arm) of the present invention to form a focus.

[0024] Figure 6 This is a schematic diagram showing the relative positions of the fast scanning delay line scanning right-angle lens and the segmented focusing ladder lens in the fast scanning delay line assembly (reference arm) of the present invention, where they form a focal point on the retina at the fundus.

[0025] Figure 7 This is a schematic diagram illustrating the principle of segmented focusing of eye tissue in this invention (the focusing lens corresponds to the first step of the segmented focusing ladder lens).

[0026] Figure 8 This is a schematic diagram illustrating the principle of segmented focusing of eye tissue in this invention (the focusing lens corresponds to the second step of the segmented focusing ladder lens).

[0027] Figure 9 This is a schematic diagram illustrating the principle of segmented focusing of eye tissue in this invention (the focusing lens corresponds to the third step of the segmented focusing ladder lens).

[0028] Figure 10 This is a schematic diagram of the simulated eye axial length information obtained by the present invention, acquired and displayed using an oscilloscope.

[0029] Figure 11 This is a schematic diagram of the simulated eye axis length information obtained by acquiring and displaying data using an oscilloscope without segmented focusing.

[0030] In the picture:

[0031] 1: Optical transmission system; 1.1: Weakly coherent light source (SLD); 1.2: Optical circulator; 1.3: Fiber optic beam splitter; 1.4: First polarization controller; 1.5: Second polarization controller; 1.6: Photodetector; 2: Fast scanning delay line assembly; 2.1: Fiber optic collimator; 2.2: Cylindrical mirror; 2.3: Reflector; 2.4: Scanning right-angle mirror; 2.5: Scanning motor; 2.6: Segmented focusing ladder mirror; 3: Sample arm optical path assembly; 3.1: Fiber optic output head; 3.2: Focusing lens; 3.3: Dichroic mirror; 4: Control system; 4.1: Acquisition control card; 4.2: Computer; 5: Video camera; 6.1: First peak; 6.2: Second peak; 6.3: Third peak; 6.4: Fourth peak; 6.5: Fifth peak. Detailed Implementation

[0032] like Figure 2 As shown, the present invention discloses a segmented focusing rapid scanning measurement system for ocular tissue biometry, comprising an optical transmission system 1, a rapid scanning delay line assembly (reference arm) 2, a sample arm optical path assembly 3, a control system 4, and a video camera 5.

[0033] The optical transmission system 1 includes an optical circulator 1.2, an optical fiber beam splitter 1.3, a first polarization controller 1.4, a second polarization controller 1.5, and a photodetector 1.6 for receiving reflected interference light signals, arranged sequentially along the optical axis of a weakly coherent light source (SLD) 1.1 measured by an eye axis measurement system.

[0034] The fast scanning delay line assembly 2 receives one beam of light split from the fiber optic beam splitter 1.3 and delays it before returning it to the fiber optic beam splitter 1.3. This fast scanning delay line assembly 2 includes a fiber optic collimator 2.1, a scanning right-angle mirror 2.4 for generating optical delay, a cylindrical mirror 2.2 and a reflecting mirror 2.3 sequentially arranged along the output light path of the scanning right-angle mirror 2.4, a scanning motor 2.5 for providing rotation of the scanning right-angle mirror 2.4, and a segmented focusing step mirror 2.6 for generating a segmented focusing effect within the tested eye tissue. The multi-channel scanning right-angle mirror 2.4 and the multi-channel segmented focusing step mirror 2.6 are respectively fixed on the circumference of the scanning motor 2.5, wherein the positions of the scanning right-angle mirror 2.4 and the segmented focusing step mirror 2.6 correspond one-to-one, as shown in the diagram. Figure 2 and Figure 3 ;

[0035] The sample arm optical path assembly 3 is used to receive another beam split from the fiber beam splitter 1.3, which is incident on the eye tissue via a segmented focusing optical path and reflected back to the fiber beam splitter 1.3. The sample arm optical path assembly 3 includes a sample arm fiber output head 3.1 output by the second polarization controller 1.5, a focusing lens 3.2 for generating a focusing effect in the eye tissue, a dichroic mirror 3.3 for deflecting and separating light, and a segmented focusing ladder mirror 2.6 for generating a segmented focusing effect in the tested eye tissue, which extends between the fiber output head 3.1 and the focusing lens 3.2.

[0036] The control system 4 includes a data acquisition and control card 4.1 for photoelectric signal conversion and motor control, and a computer 4.2;

[0037] Video camera 5 is used to detect video images of the cornea.

[0038] This invention discloses a segmented focusing rapid scanning measurement method for ocular tissue biometry, comprising the following steps:

[0039] S1. The weak coherent light emitted from the weak coherent light source (SLD) 1.1 is incident on port a of the optical circulator 1.2 and output through port b of the optical circulator 1.2 to port I of the fiber beam splitter 1.3. The fiber beam splitter 1.3 splits the input light into two paths to ports III and IV. The output beam from port III is transmitted through the first polarization controller 1.4 to the fiber collimating lens 2.1 of the fast scanning delay line assembly 2. The collimated incident light is projected onto the scanning right-angle lens 2.4 used to generate optical delay. The light emitted from the scanning right-angle lens 2.4 is reflected back to the fiber collimating lens 2.1 through the cylindrical lens 2.2 and the reflecting mirror 2.3. The light then returns to port III of the fiber beam splitter 1.3 through the first polarization controller 1.4 and converges with the light returning from the sample arm.

[0040] S2. Another beam output from port IV of the fiber optic beam splitter 1.3 is sent to the fiber optic output head 3.1 of the sample arm optical path assembly 3 via the second polarization controller 1.5, and then passes through the segmented focusing ladder mirror 2.6 along the output optical axis, the focusing lens 3.2 which produces a focusing effect in the eye tissue, and the dichroic mirror 3.3 which deflects and separates the light to project the measurement light onto the eye tissue.

[0041] S3. Different depth layers of the eye tissue reflect and scatter the incident light. One reflected light returns through the original sample arm optical path to port IV of the fiber optic beam splitter 1.3, and converges with the light returning from the reference arm. Due to the optical delay generated by the scanning right-angle mirror 2.4 in the reference arm rotating with the scanning motor 2.5, when the optical path difference of the two reflected light rays reaching the fiber optic beam splitter 1.3 is equal, an interference bright fringe corresponding to the tissue layer of the sample being tested will be generated. This light ray carrying interference information, after passing through port II of the fiber optic beam splitter 1.3, together with the light ray returning through port c of the optical circulator 1.2, is received by the photodetector 1.6 to form an electrical signal.

[0042] S4. After sampling and processing by the control system 4, which consists of the acquisition control card 4.1 and the computer 4.2, the position information of different reflection layers inside the tested tissue is obtained, that is, the tissue position information in the axial length direction.

[0043] When the point light source formed by the fiber optic output head 3.1 of the sample arm optical path assembly 3 is focused and imaged at the anterior segment cornea after passing through the segmented focusing ladder lens 2.6 and the focusing lens 3.2, the relative positions of the fast scanning delay line scanning right-angle lens 2.4 and the segmented focusing ladder lens 2.6 in the fast scanning delay line assembly (reference arm) 2 of this invention are as follows: Figure 4 As shown, θ1 corresponds to the position of the scanning right-angle lens 2.4 and the segmented focusing ladder lens 2.6 when imaging with a point light source at the anterior segment cornea. Figure 4 As can be seen from the diagram, when the angle between the scanning right-angle mirror 2.4 and the vertical axis y-y' is θ1, the first step thickness W1 of the segmented focusing escalator mirror 2.6 (see...) Figure 7 The portion is positioned precisely between the fiber optic output head 3.1 and the focusing lens 3.2. At this point, the point light source formed by the fiber optic output head 3.1 of the sample arm optical path assembly 3 passes through the W1 segment of the segmented focusing ladder lens 2.6 and the focusing lens 3.2, forming a converging point light source image at the anterior segment cornea (see imaging principle diagram). Figure 7 ).

[0044] When the point light source formed by the fiber optic output head 3.1 of the sample arm optical path assembly 3 converges and forms an image at the lens after passing through the segmented focusing ladder lens 2.6 and the focusing lens 3.2, the relative positions of the fast scanning delay line scanning right-angle lens 2.4 and the segmented focusing ladder lens 2.6 in the fast scanning delay line assembly (reference arm) 2 of this invention are as follows: Figure 5 As shown, θ2 corresponds to the position of the scanning right-angle lens 2.4 and the segmented focusing ladder lens 2.6 when imaging a point light source at the lens. Figure 5 As can be seen from the diagram, when the angle between the scanning right-angle mirror 2.4 and the vertical axis y-y' is θ2, the second step thickness W2 of the piecewise focusing step mirror 2.6 (see...) Figure 8The portion is positioned precisely between the fiber optic output head 3.1 and the focusing lens 3.2. At this point, the point light source formed by the fiber optic output head 3.1 of the sample arm optical path assembly 3 passes through the W2 segment of the segmented focusing ladder lens 2.6 and the focusing lens 3.2, forming a converging point light source image at the lens (see imaging principle diagram). Figure 8 ).

[0045] When the point light source formed by the fiber optic output head 3.1 of sample arm 3 converges and forms an image at the retina after passing through the segmented focusing ladder lens 2.6 and the focusing lens 3.2, the relative positions of the fast scanning delay line scanning right-angle lens 2.4 and the segmented focusing ladder lens 2.6 in the fast scanning delay line assembly (reference arm) 2 of this invention are as follows: Figure 6 As shown, θ3 corresponds to the position of the scanning right-angle lens 2.4 and the segmented focusing step lens 2.6 when imaging a point light source at the retina. The figure shows that when the angle between the scanning right-angle lens 2.4 and the vertical axis y-y' is θ3, the third step thickness W3 of the segmented focusing step lens 2.6 (see figure) Figure 9 The portion is positioned precisely between the fiber optic output head 3.1 and the focusing lens 3.2. At this point, the point light source formed by the fiber optic output head 3.1 of the sample arm optical path assembly 3 passes through the W3 segment of the segmented focusing ladder lens 2.6 and the focusing lens 3.2, forming a converging point light source image at the retina of the fundus (see the imaging principle diagram). Figure 9 ).

[0046] like Figures 7 to 9 As shown, where: O is the location of the fiber optic output head 3.1 of the sample arm optical path assembly 3; O' is the actual point source position formed after O is refracted by the segmented focusing ladder mirror 2.6; L0 is the distance between the light output head 3.1 and the focusing lens 3.2, i.e., the object distance of the point source; W i (Examples: W1, W2, W3) represent the 2.6mm thickness of the segmented focusing step mirror corresponding to different focusing positions; L i (Examples: L1, L2, L3) represent the new point light source object distances formed after refraction by the segmented focusing ladder mirror 2.6;

[0047] Let the focal length of the focusing lens 3.2 be f, and the image distance formed by the point light source through the focusing lens 3.2 be h. i ,

[0048] (1)

[0049] The position of the point light source in the eye tissue, i.e. the focusing position, can be obtained from the lens imaging formula (1).

[0050] By controlling the thickness of the segmented focusing ladder lens 2.6 and the position of the scanning delay line scanning right angle lens 2.4, the measurement light can be controlled to focus synchronously on the cornea, lens, and retina within the eye tissues, thereby improving the signal-to-noise ratio of the detection signal while performing high-speed scanning measurement.

[0051] like Figure 10 and Figure 11 As shown, the peaks in the two figures are as follows: the first peak 6.1 corresponds to the interference light signal formed by the anterior surface of the cornea; the second peak 6.2 corresponds to the interference light signal formed by the posterior surface of the cornea; the third peak 6.3 corresponds to the interference light signal formed by the anterior surface of the lens; the fourth peak 6.4 corresponds to the interference light signal formed by the posterior surface of the lens; and the fifth peak 6.5 corresponds to the interference signal formed by the retina.

[0052] A comparison of the two figures shows that the amplitude of the interference light signal obtained by using the present invention is significantly higher than that obtained without segmented focusing, especially in the intraocular lens and retina, where the advantage is obvious, which can effectively improve the signal-to-noise ratio of the axial length measurement information.

[0053] The embodiments of the present invention have been described in detail above, but the content described is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of this patent.

Claims

1. A segmented focus fast scanning measurement system for ocular tissue biometry, characterized by: The system includes a fast scanning delay line assembly and a sample arm optical path assembly. The fast scanning delay line assembly receives one beam of light split from the optical transmission system and delays it before returning it to the optical transmission system. This fast scanning delay line assembly includes a fiber collimator, a scanning right-angle mirror for generating optical delay, and a cylindrical mirror and a reflecting mirror sequentially arranged along the exit beam path of the scanning right-angle mirror, as well as a segmented focusing ladder mirror for generating a segmented focusing effect within the tested eye tissue. The sample arm optical path assembly receives another beam of light split from the optical transmission system, which enters the eye tissue via the segmented focusing path and is reflected back to the optical transmission system by the eye tissue. This sample arm optical path assembly includes a fiber optic output head, a focusing lens for generating a focusing effect within the eye tissue, a dichroic mirror for deflecting and separating the light, and a segmented focusing ladder mirror for generating a segmented focusing effect within the tested eye tissue extending between the fiber optic output head and the focusing lens.

2. The segmented focus fast scanning measuring system for eye tissue biometry according to claim 1 characterized by: The optical transmission system includes an optical circulator, an optical fiber beam splitter, a first polarization controller, a second polarization controller, and a photodetector for receiving reflected interference light signals, arranged sequentially along the optical axis of a weakly coherent light source.

3. The segmented focus fast scanning measuring system for eye tissue biometry according to claim 2, characterized in that: The fast scanning delay line assembly is used to receive one beam of light split from the fiber optic beam splitter and return it to the fiber optic beam splitter after delay; the sample arm optical path assembly is used to receive another beam of light split from the fiber optic beam splitter, which is incident on the eye tissue through a segmented focusing optical path and reflected back to the fiber optic beam splitter by the eye tissue.

4. The segmented focus fast scanning measuring system for ocular tissue biometry according to any of claims 1 to 3, characterized in that: The multiple scanning right-angle mirrors and the multiple segmented focusing stepped mirrors are respectively fixed on the circumference of the scanning motor, wherein the positions of the scanning right-angle mirrors and the segmented focusing stepped mirrors correspond one-to-one.

5. The segmented focus fast scanning measuring system for eye tissue biometry according to claim 4, characterized in that: It also includes a control system and a video camera. The control system includes a data acquisition and control card and a computer for photoelectric signal conversion and motor control; the video camera is used to detect video images of the cornea.

6. The method of measuring according to claim 5, wherein: Includes the following steps: S1. Weakly coherent light emitted from a weakly coherent light source is incident on port a of the optical circulator, and output through port b of the optical circulator to port I of the fiber optic beam splitter. The fiber optic beam splitter splits the input light into two paths to ports III and IV. The beam output from port III is transmitted to the fiber collimating lens of the fast scanning delay line assembly via the first polarization controller. The collimated incident light is projected onto the scanning right-angle lens used to generate optical delay. The light emitted from the scanning right-angle lens is reflected back to the fiber collimating lens via the cylindrical mirror and the reflecting mirror, and returns to port III of the fiber optic beam splitter via the first polarization controller, where it converges with the light returning from the sample arm. S2. The beam output from the fiber optic beam splitter port IV is sent to the fiber optic output head of the sample arm optical path assembly via the second polarization controller, and then passes through the segmented focusing ladder mirror along the output optical axis. The focusing lens, which generates a focusing effect in the eye tissue, then projects the measurement light onto the eye tissue through the dichroic mirror that deflects and separates the light. S3, the different depth layers of the eye tissue form reflection and scattering to the incident light, a part of the reflected light returns to the fiber beam splitter port IV through the original sample arm optical path, and converges with the light returned by the fast scanning delay line assembly; due to the optical delay caused by the rotation of the scanning mirror in the fast scanning delay line assembly, when the optical path difference of the two reflected lights reaching the fiber beam splitter is equal, an interference bright fringe corresponding to the measured sample tissue layer is generated, and the light with interference information is accepted by the photodetector together with the light returned through the optical circulator port C after passing through the fiber beam splitter port II, forming an electrical signal; S4, the control system composed of the acquisition control card and the computer samples and processes to obtain the position information of the different reflection layers in the measured tissue, that is, the position information of the tissue in the ocular axis length direction.

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