Optical system and method for measuring axial length of eye

Abstract

The invention discloses an optical system and method for measuring the axial length of the eye, the optical system comprises an OCT light source module, an OCT imaging module, a posterior segment OCT sample arm module and an anterior segment fracture imaging assembly, the OCT light source module provides measuring light, the measuring light penetrates through the posterior segment OCT sample arm module and then enters the fundus of the human eye to be measured, and the anterior segment fracture imaging assembly is used for imaging the anterior segment fracture. The OCT imaging module receives the measuring light to obtain a posterior segment OCT image; the anterior segment fissure imaging assembly comprises an anterior segment fissure light source module, an anterior segment fissure imaging module and an anterior segment fissure imaging adjusting light path module, the anterior segment fissure light source module provides fissure light, and the fissure light penetrates through the anterior segment fissure imaging adjusting light path module and then is focused on the anterior segment of a person to be detected; the anterior segment fissure imaging module receives the fissure light to obtain an anterior segment fissure image; and respectively acquiring first optical path data and second optical path data by using the posterior segment OCT image and the anterior segment fracture image so as to calculate the axial length of the eye. According to the invention, the influence of eye movement of the to-be-measured eye is avoided, and the eye axis length measurement precision is improved.

Description

[0001] This application is a divisional application filed on September 18, 2024, with application number 2024112993305, entitled "An optical system and method for measuring axial length of the eye". Technical Field

[0002] This invention relates to the field of medical device technology, and in particular to an optical system and method for measuring axial length of the eye. Background Technology

[0003] The number of elderly people suffering from cataracts is increasing, and intraocular lens transplantation is currently a widely used and effective treatment for cataracts. However, the calculation of intraocular lens measurements requires numerous parameters, such as corneal anterior and posterior surface curvature, corneal thickness, anterior chamber depth, lens thickness, lens anterior and posterior surface curvature, axial length, white-to-white distance, and pupil diameter. These parameters are numerous, and often require testing with multiple medical devices to obtain complete data. Therefore, a medical device that can obtain all of these data in a single unit would not only improve the convenience but also the accuracy of measurements for patients. Furthermore, with the increasing number of teenagers with myopia, the situation regarding myopia prevention and control is becoming increasingly severe. Measuring axial length is an important reference indicator for myopia prevention and control; therefore, the development of devices that can easily and inexpensively measure numerous ophthalmic parameters is a trend in ophthalmic medical equipment development.

[0004] Optical coherence tomography (OCT) is an emerging optical imaging technology that, compared to traditional clinical imaging methods, offers advantages such as high resolution, fast imaging speed, no radiation damage, moderate cost, and compact structure. It is an important potential tool for basic medical research and clinical diagnostic applications. Currently, among various ophthalmic devices that use optical instruments, OCT devices for ophthalmic examination and treatment have become indispensable for the diagnosis of ophthalmic diseases.

[0005] In patent document 201911073986.4, lateral corneal imaging is used to correct for the influence of eye movement during axial length measurement. However, lateral corneal imaging is easily affected by ambient light, and the cornea is relatively transparent, making it difficult to identify the corneal apex, resulting in a large error. In patent documents 201410135999.0 and 202011120798.5, anterior and posterior segment OCT switching technology is used to achieve corneal and posterior segment OCT imaging to measure axial length. However, the anterior and posterior segment OCT switching process requires a lot of time, which may be affected by eye movement, leading to a decrease in the reliability of axial length measurement.

[0006] The above background information is provided only to aid in understanding the concept and technical solution of this invention. It does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above information was disclosed on the filing date of this patent application, the above background information should not be used to evaluate the novelty and inventiveness of this application. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention proposes an optical system and method for measuring axial length, which avoids the influence of eye movement in the subject and improves the accuracy of axial length measurement.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention discloses an optical system for measuring axial length of the eye, comprising an OCT light source module, an OCT imaging module, a posterior segment OCT sample arm module, and an anterior segment slit imaging component, wherein: The OCT light source module is used to provide measurement light. The measurement light passes through the posterior segment OCT sample arm module and is incident on the fundus of the subject's eye. The OCT imaging module receives the measurement light returned from the fundus of the subject's eye to obtain an OCT image of the posterior segment. The anterior segment slit imaging component includes an anterior segment slit light source module, an anterior segment slit imaging module, and an anterior segment slit imaging adjustment optical path module. The anterior segment slit light source module is used to provide slit light. The slit light passes through the anterior segment slit imaging adjustment optical path module and is focused on the anterior segment of the subject. The anterior segment slit imaging module receives the returned slit light to obtain an anterior segment slit image. Using the posterior segment OCT image and the anterior segment slit image, first optical path data and second optical path data are obtained respectively, and the axial length is calculated using the first optical path data and the second optical path data.

[0009] Preferably, the anterior segment slit imaging module includes an anterior segment slit imaging lens 1801 and an anterior segment slit imaging device 1803. The slit light emitted by the anterior segment slit light source module is focused on the anterior segment of the subject and returns to the anterior segment slit light signal, which passes through the anterior segment slit imaging lens 1801 and is received by the anterior segment slit imaging device 1803. The anterior segment slit imaging device 1803 obtains an anterior segment slit image based on the anterior segment slit light signal.

[0010] Preferably, the anterior segment slit imaging adjustment optical path module includes an eyepiece objective 1305, which is located on the optical path in a first direction, wherein the optical path in the first direction is perpendicular to the human eye under test, and the anterior segment slit imaging lens 1801 and the anterior segment slit imaging device 1803 are respectively disposed below the eyepiece objective 1305.

[0011] Preferably, the anterior segment slit light source module includes an anterior segment slit light source 1809 and a front beam splitter 1303. The slit light emitted by the anterior segment slit light source 1809 passes through the front beam splitter 1303 and is then focused onto the anterior segment of the subject after passing through the anterior segment slit imaging adjustment optical path module.

[0012] Preferably, the posterior segment OCT sample arm module includes an optical path scanning device 1109 and a posterior segment OCT imaging adjustment optical path unit. The posterior segment OCT imaging adjustment optical path unit and the anterior segment OCT insertion lens 1501 form an anterior segment OCT imaging adjustment optical path unit. The anterior segment slit imaging adjustment optical path module uses the anterior segment OCT imaging adjustment optical path unit. The anterior segment slit light source module uses the OCT light source module and the optical path scanning device 1109 to generate slit light. The measurement light provided by the OCT light source module emits slit light after being scanned in one dimension by the optical path scanning device 1109 and passes through the anterior segment OCT imaging adjustment optical path unit before being focused on the anterior segment of the subject.

[0013] Preferably, the posterior segment OCT sample arm module includes an optical path scanning device 1109 and a posterior segment OCT imaging adjustment optical path unit. The posterior segment OCT imaging adjustment optical path unit and the anterior segment OCT insertion lens 1501 form the anterior segment OCT imaging adjustment optical path unit. The anterior segment slit imaging adjustment optical path module uses the anterior segment OCT imaging adjustment optical path unit. The anterior segment slit light source module uses an anterior segment slit light source 3809, a wavelength division multiplexer 3807, an optical fiber 1106, and the optical path scanning device 1109 to generate slit light. The light output from the anterior segment slit light source 3809 is coupled through the wavelength division multiplexer 3807 and transmitted to the optical fiber 1106. The beam output from the optical fiber 1106 is scanned in one dimension by the optical path scanning device 1109 and emits slit light. After passing through the anterior segment OCT imaging adjustment optical path unit, it is focused on the anterior segment of the subject.

[0014] Preferably, the posterior segment OCT sample arm module includes an optical path scanning device 1109 and a posterior segment OCT imaging adjustment optical path unit. The posterior segment OCT imaging adjustment optical path unit and the anterior segment OCT insertion lens 1501 form the anterior segment OCT imaging adjustment optical path unit. The anterior segment slit imaging adjustment optical path module uses the anterior segment OCT imaging adjustment optical path unit. The anterior segment slit light source module uses an anterior segment slit light source 4809, a parallel optical fiber 2106, and the optical path scanning device 1109 to generate slit light. The light output from the anterior segment slit light source 4809 passes through the parallel optical fiber 2106. The beam output from the parallel optical fiber 2106 is scanned in one dimension by the optical path scanning device 1109, emits slit light, passes through the anterior segment OCT imaging adjustment optical path unit, and is focused on the anterior segment of the subject.

[0015] Preferably, the posterior segment OCT sample arm module includes an optical path scanning device 1109 and a posterior segment OCT imaging adjustment optical path unit. The anterior segment slit imaging adjustment optical path module adopts the posterior segment OCT imaging adjustment optical path unit. The anterior segment slit light source module includes an anterior segment slit light source 5809, a lens 5807, and a beam splitter 5805. The light emitted from the anterior segment slit light source 5809 passes through the lens 5807, is reflected by the beam splitter 5805, and is then scanned in one dimension by the optical path scanning device 1109 to form slit light. After passing through the anterior segment slit imaging adjustment optical path module, the light is focused on the anterior segment of the subject.

[0016] Preferably, the posterior segment OCT imaging adjustment optical path unit includes a posterior segment OCT field lens 1301, a front beam splitter 1303, and an eyepiece objective lens 1305; the measurement light provided by the OCT light source module is reflected by the optical path scanning device 1109, passes through the posterior segment OCT field lens 1301, and is then reflected by the front beam splitter 1303 to the eyepiece objective lens 1305. After passing through the subject's eye, the light converges to the fundus of the subject's eye, so that the light signal is transmitted back to the posterior segment and transmitted to the OCT imaging module. The OCT imaging module acquires a posterior segment OCT image based on the posterior segment light signal. The anterior segment OCT imaging adjustment optical path unit is formed by inserting an anterior segment OCT insertion lens 1501 into the optical path formed by the posterior segment OCT imaging adjustment optical path unit. The slit light passes sequentially through the posterior segment OCT field lens 1301 and the anterior segment OCT insertion lens 1501, and is then reflected by the front beam splitter 1303 to the eyepiece objective lens 1305, converging on the anterior segment of the subject to be tested, so as to return the anterior segment slit light signal to the anterior segment slit imaging module. The anterior segment slit imaging module acquires the anterior segment slit image based on the anterior segment slit light signal.

[0017] Preferably, the first optical path data refers to the optical path hRetinal from the top of the posterior segment OCT image to the retinal signal in the posterior segment OCT image, which is measured based on the posterior segment OCT image of the eye under test; and the second optical path data refers to the optical path hCornea from the top of the anterior segment slit image to the corneal apex of the eye under test, which is measured based on the anterior segment slit image of the eye under test. The axial length of the eye is calculated using the first optical path data and the second optical path data, including: calculating the axial length Leye of the eye under test based on the optical path change X of the posterior segment OCT sample arm module when acquiring the OCT image of the posterior segment of the eye under test, as well as the measured optical path hRetinal and optical path hCornea.

[0018] In a second aspect, the present invention discloses a method for measuring axial length of the eye, characterized in that the axial length of the human eye to be measured is measured using the optical system described in the first aspect, comprising the following steps: Acquire an OCT image of the posterior segment of the eye of the subject to be tested, and measure the optical path hRetinal from the top of the posterior segment OCT image to the retinal signal in the posterior segment OCT image based on the OCT image of the posterior segment of the eye of the subject to be tested. Acquire an anterior segment slit image of the eye under test, and measure the optical path hCornea from the top of the anterior segment slit image to the corneal apex of the eye under test based on the anterior segment slit image of the eye under test. The axial length Leye of the human eye under test is calculated based on the optical path change X of the posterior segment OCT sample arm module when acquiring the OCT image of the posterior segment of the human eye under test, as well as the measured optical path hRetinal and optical path hCornea.

[0019] Preferably, the axial length (Leye) of the human eye being tested is calculated using the following formula: Leye=△L+X-hCornea+hRetinal; Where △L represents the spatial distance between the top of the posterior segment OCT image and the top of the anterior segment slit image, and X represents the change in optical path of the posterior segment OCT sample arm module when acquiring the posterior segment OCT image of the human eye under test.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: The optical system and method for measuring axial length proposed in the present invention further measure the axial length by acquiring posterior segment OCT images and anterior segment slit images respectively. The anterior segment slit imaging achieves accurate positioning of the cornea. Combined with posterior segment OCT image acquisition, the switching time can be reduced or even eliminated, thereby avoiding the influence of the subject's eye movement and improving the accuracy of axial length measurement.

[0021] In a further scheme, by adding a separate anterior segment slit light source to generate slit light, and by using different imaging schemes to acquire posterior segment OCT images and anterior segment slit images, both can be acquired simultaneously, thereby minimizing the influence of eye movement on the subject and further improving the measurement accuracy of axial length.

[0022] In a further solution, an OCT light source module or a separate anterior segment slit light source is combined with an optical path scanning device to generate slit light. This is then combined with an anterior segment OCT imaging adjustment optical path unit, allowing the slit light to be focused onto the cornea of ​​the subject, thereby acquiring an anterior segment slit image. This solution eliminates the need for additional optical path debugging, reducing system debugging difficulty and increasing system debugging speed. Moreover, only the anterior segment OCT insertion lens needs to be adjusted between acquiring posterior segment OCT images and anterior segment slit images, without adjusting the optical path. The switching time is shorter, faster than existing technologies, and more easily avoids the influence of eye movements during long-term axial length measurements. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the ophthalmic optical biometry system according to Embodiment 1 of the present invention; Figure 2 yes Figure 1 Optical path diagram of the posterior segment OCT imaging system of the China Ophthalmic Optical Biometry System; Figure 3 yes Figure 1 Optical path diagram of the anterior segment OCT imaging system of the Optical Biometry System of the Chinese Academy of Ophthalmic Sciences; Figure 4a yes Figure 1 Front view of the anterior segment camera module of the optical biometry system at the Chinese Academy of Ophthalmic Sciences; Figure 4b yes Figure 1 Top view of the anterior segment camera module of the Chinese Ophthalmic Optical Biometry System; Figure 5 yes Figure 1 Optical path diagram of anterior segment slit imaging using the optical biometry system of the Chinese Academy of Ophthalmic Sciences; Figure 6 yes Figure 1 A schematic diagram of the fixation optics module of the Zhongyanke Optical Biometry System; Figure 7 This is a schematic diagram of axial length measurement; Figure 8 This is a schematic diagram of the ophthalmic optical biometry system according to Embodiment 2 of the present invention; Figure 9 yes Figure 8 Optical path diagram of anterior segment slit imaging using the optical biometry system of the Chinese Academy of Ophthalmic Sciences; Figure 10 yes Figure 8 A schematic diagram of the fixation optics module of the Zhongyanke Optical Biometry System; Figure 11 This is a schematic diagram of the ophthalmic optical biometry system according to Embodiment 3 of the present invention; Figure 12 yes Figure 11A schematic diagram of the optical fiber structure of the optical biometry system in the Chinese Academy of Ophthalmic Sciences. Figure 13 yes Figure 11 Optical path diagram of the posterior segment OCT imaging system of the China Ophthalmic Optical Biometry System; Figure 14 yes Figure 11 Optical path diagram of the anterior segment OCT imaging system of the Optical Biometry System of the Chinese Academy of Ophthalmic Sciences; Figure 15 yes Figure 11 Optical path diagram of anterior segment slit imaging using the optical biometry system of the Chinese Academy of Ophthalmic Sciences; Figure 16 This is a schematic diagram of the ophthalmic optical biometry system according to Embodiment 4 of the present invention; Figure 17 yes Figure 16 A schematic diagram of the parallel optical fiber structure of the optical biometry system in the Chinese Academy of Ophthalmic Sciences. Figure 18 This is a schematic diagram of the structure of parallel optical fibers in existing technology; Figure 19 yes Figure 16 Optical path diagram of anterior segment slit imaging using the optical biometry system of the Chinese Academy of Ophthalmic Sciences; Figure 20 This is a schematic diagram of the ophthalmic optical biometry system according to Embodiment 5 of the present invention; Figure 21 yes Figure 20 Optical path diagram of anterior segment slit imaging using the optical biometry system of the Chinese Academy of Ophthalmic Sciences.

[0024] Explanation of reference numerals in the attached figures: 10, Probe module; 1101, OCT light source; 1103, Fiber optic coupler; 1105, Polarization controller; 1106, Fiber optic cable; 11061, Fiber core; 11063, Cladding; 11065, Sheath; 1107, Fiber optic collimator; 1109, Optical path scanning device; 11091, X-direction scanning device; 11093, Y-direction scanning device; 1120, Reference arm module; 1141. Detector; 1143. Computer; 1301. Posterior segment OCT field lens; 1303. Anterior beam splitter; 1305. Eyepiece objective; 1501. Anterior segment OCT insertion lens; 1701. Fixation light source; 1703. Gazing optical path lens; 18. Combined module; 1801. Anterior segment slit imaging lens; 1803. Anterior segment slit imaging device; 1807. Angle-beam splitter; 1809. Anterior segment Anterior segment slit light source; 1901, Illumination source; 1903, Iridescent repeater; 1905, Iridescent beam splitter; 1907, Anterior segment camera lens; 1909, Anterior segment camera device; E, Human eye under test; Er, Fundus; L1, Optical axis; 2106, Parallel optical fiber; 21061, OCT optical path core; 21062, Anterior segment slit illumination optical path core; 21063, OCT optical path cladding; 21065, Sheath 3106, Dual-core optical fiber; 31061, Fiber core; 31062, Fiber core; 31063, Fiber cladding; 31064, Fiber cladding; 31065, Sheath; 31066, Sheath; 31069, Large sheath; 3807, Wavelength division multiplexer; 3809, Anterior segment slit source; 4809, Anterior segment slit source; 5805, Beam splitter; 5807, Lens; 5809, Anterior segment slit source. Detailed Implementation

[0025] The present invention will now be described in further detail with reference to specific embodiments and the accompanying drawings. The same reference numerals denote the same parts unless otherwise specified. It should be emphasized that the following description is merely exemplary and not intended to limit the scope or application of the invention.

[0026] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments to provide a better understanding of the invention. However, the following embodiments do not limit the scope of the invention. Furthermore, it should be noted that the illustrations provided in the following embodiments are merely schematic representations of the basic concept of the invention. The drawings only show components relevant to the invention and are not drawn according to the actual number, shape, and size of the components in implementation. In actual implementation, the shape, quantity, and proportion of each component can be arbitrarily changed, and the component layout may also be more complex.

[0027] It should be understood that the terms "upper", "lower", "front", "rear", "inner", "outer", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0028] The ophthalmic optical biometry system proposed in this invention is mainly used for measuring and examining the optical parameters of the patient's eye. It can measure numerous ophthalmic parameters, including anterior segment OCT images, posterior segment OCT images, anterior segment imaging, axial length, anterior chamber depth, and white-to-white distance. The system primarily utilizes optical coherence tomography (OCT) technology, combined with anterior and posterior segment OCT acquisition techniques, anterior segment slit imaging, and anterior segment imaging, to measure axial length and other relevant ophthalmic parameters. Through iris recognition technology, automatic anterior segment OCT image recognition technology, and automatic posterior segment OCT image recognition technology, the system achieves fully automated detection. The axial length measurement technology uses anterior segment slit imaging to accurately locate the cornea (i.e., the anterior segment), combined with posterior segment OCT acquisition technology.

[0029] This invention employs a rapid anterior-posterior segment switching OCT system, combined with anterior segment imaging and automatic recognition technology, to solve the detection of numerous optical parameters of the human eye. This meets the measurement needs of different parts of the eye, obtaining accurate data on many important human eye parameters to satisfy the needs of doctors' clinical diagnosis. Through iris recognition technology, automatic recognition of anterior segment OCT images, and automatic recognition of posterior segment OCT images, the system achieves fully automated detection.

[0030] A preferred embodiment of the present invention discloses an optical system for measuring axial length, comprising an OCT light source module, an OCT imaging module, a posterior segment OCT sample arm module, and an anterior segment slit imaging component. The OCT light source module provides measurement light, which passes through the posterior segment OCT sample arm module and is incident on the fundus of the subject's eye. The OCT imaging module receives the measurement light reflected from the fundus of the subject's eye to obtain a posterior segment OCT image. The anterior segment slit imaging component includes an anterior segment slit light source module, an anterior segment slit imaging module, and an anterior segment slit imaging adjustment optical path module. The anterior segment slit light source module provides slit light, which passes through the anterior segment slit imaging adjustment optical path module and is focused on the anterior segment of the subject's eye. The anterior segment slit imaging module receives the reflected slit light to obtain an anterior segment slit image. First optical path data and second optical path data are obtained using the posterior segment OCT image and the anterior segment slit image, respectively. The axial length is calculated using the first optical path data and the second optical path data.

[0031] The first optical path data refers to the optical path hRetinal from the top of the posterior segment OCT image to the retinal signal in the posterior segment OCT image, measured from the posterior segment OCT image of the subject eye. The second optical path data refers to the optical path hCornea from the top of the anterior segment slit image to the corneal apex of the subject eye, measured from the anterior segment slit image of the subject eye. The axial length is calculated using the first and second optical path data, including: calculating the axial length Leye of the subject eye based on the optical path change X of the posterior segment OCT sample arm module when acquiring the posterior segment OCT image of the subject eye, as well as the measured optical path hRetinal and optical path hCornea.

[0032] The anterior segment slit imaging module includes an anterior segment slit imaging lens 1801 and an anterior segment slit imaging device 1803. The slit light emitted from the anterior segment slit light source module is focused on the anterior segment of the subject and returns as an anterior segment slit light signal. This signal passes through the anterior segment slit imaging lens 1801 and is received by the anterior segment slit imaging device 1803. The anterior segment slit imaging device 1803 obtains an anterior segment slit image based on the anterior segment slit light signal. Further, the anterior segment slit imaging adjustment optical path module includes an eyepiece objective 1305, which is located on the optical path in a first direction, perpendicular to the subject's eye. The anterior segment slit imaging lens 1801 and the anterior segment slit imaging device 1803 are respectively positioned below the eyepiece objective 1305. The anterior segment slit imaging modules in Embodiments 1 to 4 described below all employ this structure.

[0033] In some preferred embodiments, such as Embodiment 1 below, the anterior segment slit light source module includes an anterior segment slit light source 1809 and a front beam splitter 1303. The slit light emitted by the anterior segment slit light source 1809 is focused onto the anterior segment of the subject after passing through the front beam splitter 1303 and the anterior segment slit imaging adjustment optical path module. Specifically, the slit light emitted by the anterior segment slit light source 1809 is reflected by the corner beam splitter 1807, then reflected by the iris beam splitter 1905, transmitted through the iris relay mirror 1903 and the front beam splitter 1303, and then focused onto the anterior segment of the subject by the eyepiece objective lens 1305.

[0034] In some preferred embodiments, such as Embodiment 2 below, the posterior segment OCT sample arm module includes an optical path scanning device 1109 and a posterior segment OCT imaging adjustment optical path unit. The posterior segment OCT imaging adjustment optical path unit and the anterior segment OCT insertion lens 1501 form the anterior segment OCT imaging adjustment optical path unit. The anterior segment slit imaging adjustment optical path module uses the anterior segment OCT imaging adjustment optical path unit. The anterior segment slit light source module uses the OCT light source module and the optical path scanning device 1109 to generate slit light. The measurement light provided by the OCT light source module emits slit light after being scanned in one dimension by the optical path scanning device 1109 and passes through the anterior segment OCT imaging adjustment optical path unit before being focused on the anterior segment of the subject.

[0035] In some preferred embodiments, such as Embodiment 3 below, the posterior segment OCT sample arm module includes an optical path scanning device 1109 and a posterior segment OCT imaging adjustment optical path unit. The posterior segment OCT imaging adjustment optical path unit and the anterior segment OCT insertion lens 1501 form the anterior segment OCT imaging adjustment optical path unit. The anterior segment slit imaging adjustment optical path module uses the anterior segment OCT imaging adjustment optical path unit. The anterior segment slit light source module uses an anterior segment slit light source 3809, a wavelength division multiplexer 3807, an optical fiber 1106, and an optical path scanning device 1109 to generate slit light. The light output from the anterior segment slit light source 3809 is coupled through the wavelength division multiplexer 3807 and transmitted to the optical fiber 1106. The beam output from the optical fiber 1106 is scanned in one dimension by the optical path scanning device 1109 and emits slit light. After passing through the anterior segment OCT imaging adjustment optical path unit, it is focused on the anterior segment of the subject.

[0036] In some preferred embodiments, such as Embodiment 4 below, the posterior segment OCT sample arm module includes an optical path scanning device 1109 and a posterior segment OCT imaging adjustment optical path unit. The posterior segment OCT imaging adjustment optical path unit and the anterior segment OCT insertion lens 1501 form the anterior segment OCT imaging adjustment optical path unit. The anterior segment slit imaging adjustment optical path module uses the anterior segment OCT imaging adjustment optical path unit. The anterior segment slit light source module uses the anterior segment slit light source 4809, parallel optical fiber 2106, and optical path scanning device 1109 to generate slit light. The light output from the anterior segment slit light source 4809 passes through the parallel optical fiber 2106. The beam output from the parallel optical fiber 2106 is scanned in one dimension by the optical path scanning device 1109 and then emits slit light. After passing through the anterior segment OCT imaging adjustment optical path unit, it is focused on the anterior segment of the subject.

[0037] Furthermore, in embodiments two, three, and four, the posterior segment OCT imaging adjustment optical path unit includes a posterior segment OCT field lens 1301, a front beam splitter 1303, and an eyepiece objective lens 1305. The measurement light provided by the OCT light source module is reflected by the optical path scanning device 1109, passes through the posterior segment OCT field lens 1301, and is then reflected by the front beam splitter 1303 to the eyepiece objective lens 1305. After passing through the subject's eye, the light converges to the fundus of the subject's eye, and the light signal returns to the posterior segment and is transmitted to the OCT imaging module. The OCT imaging module acquires the eye based on the posterior segment light signal. Posterior segment OCT image; The anterior segment OCT imaging adjustment optical path unit is formed by inserting the anterior segment OCT insertion mirror 1501 into the optical path formed by the posterior segment OCT imaging adjustment optical path unit. The slit light passes sequentially through the posterior segment OCT field mirror 1301 and the anterior segment OCT insertion mirror 1501, and is then reflected by the front beam splitter 1303 to the eyepiece objective 1305, converging on the anterior segment of the subject to be tested, so as to return the anterior segment slit light signal to the anterior segment slit imaging module. The anterior segment slit imaging module acquires the anterior segment slit image based on the anterior segment slit light signal.

[0038] The ophthalmic optical biometry system proposed in this invention will be further described in detail below with reference to several specific embodiments.

[0039] Example 1 Embodiment 1 of this invention discloses an ophthalmic optical biometry system, including an OCT imaging module, a posterior segment OCT sample arm module, an anterior segment OCT insertion lens, a fixation optics module, an anterior segment camera module, and an anterior segment slit imaging module. Each module performs a corresponding function, and some optical components are shared among the modules. The modules are appropriately combined to form the ophthalmic optical biometry system.

[0040] The computer 1143 controls the insertion and exit of the anterior segment OCT insertion lens 1501, and coordinates with the optical fiber collimating lens 1107 to translate along the optical axis to achieve optical path switching and OCT imaging of different parts of the human eye.

[0041] like Figure 1The diagram shows the structure of the ophthalmic optical biometry system according to Embodiment 1 of the present invention. The probe module 10 includes: a posterior segment OCT sample arm module, an anterior segment OCT insertion lens, a fixation optics module, an anterior segment camera module, and an anterior segment slit imaging module. The probe module 10 is driven by three motors (not shown in the diagram), enabling three-dimensional translation in X / Y / Z directions. In this embodiment, the X-axis is defined as the axis perpendicular to the paper, the Y-axis as the axis parallel to the paper in the vertical direction, and the Z-axis as the axis parallel to the paper in the horizontal direction. That is, the X-axis and Y-axis directions refer to the horizontal and vertical axes on a plane parallel to the outer surface of the human eye E, respectively, while the Z-axis direction refers to the direction perpendicular to the plane parallel to the outer surface of the human eye E. These definitions are for illustrative purposes only and are not intended to limit the scope of the invention.

[0042] (1) OCT imaging system The OCT imaging module includes an OCT light source 1101, an optical fiber coupler 1103, a reference arm module 1120, a detector 1141, a computer 1143, a polarization controller 1105, and a sample arm module. The OCT light source 1101 outputs near-infrared light. The sample arm module includes a posterior segment OCT sample arm module and an anterior segment insertion lens 1501. The computer 1143 in this application is not a traditional PC, but rather a circuit control and processing system capable of performing calculations, control, storage, and display functions.

[0043] The optical path of the OCT imaging module includes an OCT light source 1101 (which can be a weakly coherent light source), whose output light is supplied to the sample arm module and reference arm module 1120 via fiber optic coupler 1103. The reference arm module 1120 has a known length, and the light supplied to it by fiber optic coupler 1103 can be further transmitted back to the fiber optic coupler 1103. The sample arm module provides light to the subject's eye E. The light scattered from the subject's eye E interferes with the light transmitted from the reference arm module 1120 via the sample arm module, polarization controller 1105, and the reference arm module 1120 in the fiber optic coupler 1103. The interference light is detected by detector 1141, processed by computer 1143, and finally displayed as an OCT image of the subject's eye E. The optical path scanning device 1109 employs a two-dimensional scanning mechanism, consisting of an X-direction scanning device 11091 and a Y-direction scanning device 11093. The optical path scanning device 1109 scans the sample (subject's eye) to achieve OCT tomographic imaging.

[0044] (2) Posterior segment OCT imaging system like Figure 2The diagram shows the optical path of the posterior segment OCT imaging system. The posterior segment OCT sample arm module includes an optical path scanning device 1109 and a posterior segment OCT imaging adjustment optical path unit. The posterior segment OCT imaging adjustment optical path unit includes a fiber optic collimator 1107, a posterior segment OCT field lens 1301, a front beam splitter 1303, and an eyepiece objective 1305. The optical path scanning device 1109 can be a one-dimensional optical path switching scanning device, or it can be two-dimensional or even three-dimensional; the optical path scanning device 1109 realizes one-dimensional to multi-dimensional scanning of the human eye E under test. The optical fiber exits through the sample arm fiber optic head (not shown in the figure), which is adjacent to the fiber optic collimator 1107; the sample arm fiber optic head and the fiber optic collimator 1107 are driven by a motor and can translate along the principal optical axis of the fiber optic collimator 1107, thereby changing the optical path of the sample arm optical path. Similarly, the matching of optical path lengths between the sample arm and the reference arm can also be achieved by changing the optical path length of the reference arm; where the optical fiber is connected to the optical fiber head of the sample arm.

[0045] During posterior segment OCT imaging, light emitted from the fiber optic collimator 1107 is reflected by the optical path scanning device 1109. The optical path scanning device 1109 is controlled by the computer 1143. After reflection by the optical path scanning device 1109, the light beam passes through the posterior segment OCT field lens 1301, is reflected by the front beam splitter 1303 to the eyepiece objective lens 1305, and finally converges to the fundus Er of the subject eye E. The detection beam of the posterior segment OCT imaging optical path system satisfies the condition that the center line of the scanning beam converges near the pupil of the subject eye, while at any given time, the OCT beam is focused on the fundus Er of the subject eye.

[0046] For different human eyes (with varying refractive powers), by adjusting the eyepiece objective 1305, the OCT beam can be focused onto the retina (Er). This effectively improves the signal-to-noise ratio and lateral resolution of the OCT image during retinal measurements.

[0047] The front beam splitter 1303 can reflect the signal light emitted by the OCT light source 1101 and transmit the fixed light emitted by the fixed light source 1701 in the fixed optical module; transmit the light emitted by the anterior segment slit light source 1809 in the anterior segment slit imaging module; and also transmit the illumination light emitted by the illumination light source 1901 in the anterior segment camera module.

[0048] At this time, the anterior segment OCT insertion lens 1501 is controlled by the computer 1143 to switch out the posterior segment OCT imaging optical path.

[0049] When measuring the fundus, scanning is performed using the X-axis scanning device 11091 and the Y-axis scanning device 11093; the optical path matching for different human eyes is achieved by the overall translation of the fiber collimating lens 1107 combined with the fiber optic head of the sample arm (not shown); the refractive adjustment for different human eyes is achieved by the translation of the eyepiece objective lens 1305 along the optical axis; finally, the acquisition of OCT images of the posterior segment of the eye is achieved, thereby obtaining important parameters of the eye structure such as retinal thickness.

[0050] (3) Anterior segment OCT imaging system like Figure 2 The diagram shown is the optical path of the anterior segment OCT imaging system. The posterior segment OCT imaging adjustment optical path unit and the anterior segment OCT insertion lens 1501 form the anterior segment OCT imaging adjustment optical path unit. Specifically, the anterior segment OCT imaging adjustment optical path unit includes a fiber optic collimator 1107, a posterior segment OCT field lens 1301, an anterior segment OCT insertion lens 1501, a front beam splitter 1303, and an eyepiece objective lens 1305. Anterior segment OCT imaging can be performed through the cooperation of the optical path scanning device 1109 and the anterior segment OCT imaging adjustment optical path unit.

[0051] During anterior segment OCT imaging, the light emitted from the fiber optic collimator 1107 is reflected by the optical path scanning device 1109, transmitted through the posterior segment OCT field lens 1301 and the anterior segment OCT insertion lens 1501, reflected by the front beam splitter 1303, and then transmitted through the eyepiece objective lens 1305, finally converging onto the anterior segment (i.e., the cornea) of the subject eye E. The probe beam of the anterior segment OCT imaging optical path system satisfies the requirement that the OCT beam is focused on the anterior segment of the eye.

[0052] At this time, the anterior segment OCT insertion mirror 1501 is inserted into the optical path under the control of the computer 1143.

[0053] When measuring the anterior and posterior surfaces of the cornea and lens, the OCT beam is focused on the middle region of the anterior segment, which can effectively improve the signal-to-noise ratio and lateral resolution of the OCT image during the measurement of the anterior and posterior surfaces of the cornea and lens.

[0054] When measuring anterior segment OCT images, scanning is performed using the optical path scanning device 1109; optical path matching required for OCT measurement is achieved through the overall translation of the fiber collimating lens 1107 combined with the sample arm fiber optic head (not shown); focusing is achieved by translating the eyepiece objective lens 1305 along the optical axis L1, or by translating the probe module 10 as a whole along the optical axis L1. Through the cooperation of the optical path scanning device 1109 and the anterior segment OCT imaging adjustment optical path unit, OCT images of the anterior and posterior surfaces of the cornea and lens can be obtained, thereby obtaining important parameters of human eye structures such as anterior and posterior surface curvature of the cornea, corneal thickness, anterior chamber depth, lens thickness, and anterior and posterior surface curvature of the lens.

[0055] (4) Anterior segment camera module like Figure 4a and Figure 4b The images shown are the front view and top view of the anterior segment camera module, respectively.

[0056] This module can be used for iris preview to guide doctors in operating the instrument and aligning the probe's optical path with the eye being tested. Alternatively, it can automatically identify the center of the iris or the center of the pupil to guide the probe module 10 in automatic three-dimensional movement, aligning it with the pupil of the eye being tested, thereby enabling the detection of the eye.

[0057] The light emitted by the illumination source 1901 (infrared light) shines into the anterior chamber of the eye E of the subject, and the light is reflected by the anterior chamber tissue. The reflected light passes through the eyepiece objective lens 1305, the front beam splitter 1303, the iris relay lens 1903, and is transmitted through the iris beam splitter 1905, then through the anterior segment camera lens 1907, and finally captured by the anterior segment camera device 1909.

[0058] The examiner uses a chin rest device (not shown) to fix the subject's head and directs the subject's fixation target to fix their eyes. Then, while observing the display screen of computer 1143, the examiner controls the movement of the chin rest device and probe 10 via a joystick, so that the anterior segment of the examined eye E enters the anterior segment imaging device 1909, and the anterior segment image is displayed on the computer 1143 screen. Alternatively, the probe 10 can be automatically moved in three dimensions by automatically identifying the iris center or pupil center position to align the pupil of the subject's eye, thereby achieving the examination of the subject's eye.

[0059] The anterior segment camera module 190 can obtain important parameters of human eye structure such as white-to-white distance and pupil diameter.

[0060] The distribution of the illumination source 1901 in the above figure is only schematic. Other distribution methods can be used in other embodiments. It is sufficient for the illumination source 1901 to illuminate the anterior segment of the subject's eye. The number can be one or more.

[0061] The iris beam splitter 1905 transmits illumination light emitted from the illumination source 1901 in the anterior segment imaging module 190, reflects the fixation light emitted from the fixation source 1701 in the fixation optics module, and reflects the light emitted from the anterior segment slit source 1809 in the anterior segment slit imaging module.

[0062] (5) Anterior segment slit imaging module like Figure 5The diagram shows a schematic of the anterior segment slit imaging module. The anterior segment slit imaging module includes a combination module 18, a front beam splitter 1303, an iris relay lens 1903, an iris beam splitter 1905, an angle beam splitter 1807, and an anterior segment slit light source 1809. The combination module 18 is composed of an eyepiece objective lens 1305, an anterior segment slit imaging lens 1801, and an anterior segment slit imaging device 1803. This combination module 18 is driven by a motor (not shown in the diagram; this motor is independent of the three motors controlled by the overall system) and can move along the Z-direction, thereby achieving refractive adjustment.

[0063] Anterior segment slit light source 1809 emits light through a blade or slit, generating slit light, or slit beam. This slit light is reflected by corner beam splitter 1807 and iris beam splitter 1905, transmitted through iris relay lens 1903 and front beam splitter 1303, and then focused onto the anterior segment of the subject by eyepiece objective lens 1305. This anterior segment slit light passes through the anterior segment tissue, is scattered by the cornea and lens, and the scattered light passes through anterior segment slit imaging lens 1801, and is finally captured by anterior segment slit imaging device 1803.

[0064] The anterior segment slit imaging optical path (including the anterior segment slit imaging lens 1801 and the anterior segment slit imaging device 1803) is preferably distributed below the eyepiece objective 1305. If it is distributed to the left / right side of the probe 10 in the X direction, it is not conducive to the simultaneous use of both eyes. If it is distributed above the eyepiece objective 1305, it is easily blocked by the eyelid.

[0065] In some embodiments, the anterior segment slit imaging device 1803 is only used to capture an anterior segment slit image near the cornea of ​​the subject's eye. The imaging range is small, but the imaging accuracy is high. The anterior segment slit image allows for accurate localization of the cornea's spatial position. For example, if the corneal thickness is approximately 550 μm, and the anterior segment slit imaging range in the Z-direction is between 0.5 and 10 mm, the localization accuracy of the cornea can be effectively improved. In other embodiments, the imaging range of the anterior segment slit imaging device 1803 is increased, allowing for the acquisition of data such as anterior chamber depth and even lens thickness.

[0066] In this embodiment, the anterior segment slit imaging optical path is distributed at an oblique angle. Therefore, the anterior segment slit imaging module combined with the anterior segment camera module can accurately identify the Z-direction position of the eye under test. Combined with the acquired posterior segment OCT image, the axial length of the eye under test can be obtained.

[0067] The angle beam splitter 1807 reflects the light emitted from the anterior segment slit light source 1809 in the anterior segment slit imaging module, and also transmits the fixation light emitted from the fixation light source 1701 in the fixation optics module.

[0068] (6) Fixation Optical Module like Figure 6 The diagram shows a fixation optics module. The fixation light source 1701 in the fixation optics module is used for the fixation target (internal fixation target) of the subject's eye E. Light from the fixation light source 1701 passes through the fixation path lens 1703 and the angle beam splitter 1807, is reflected by the iris beam splitter 1905, and then transmitted through the iris relay lens 1903 and the front beam splitter 1303. The light then passes through the eyepiece objective lens 1305 and enters the subject's eye E. Finally, the internal fixation target is projected onto the fundus Er of the subject's eye E.

[0069] The Fixed Vision 1701 light source can be a single LED, or an LCD screen, OLED screen, or LED array screen, etc.

[0070] During posterior segment OCT imaging, the clarity of the fixation point varies among different eyes, causing discomfort for the subject and hindering fixation of the subject's eye E. Because the optical path of posterior segment OCT imaging, after adjustment via the eyepiece objective 1305, can focus on the fundus Er (retina) of the subject's eye E, the scan lines can be clearly seen. Since the posterior segment OCT imaging optical path and the fixation optical path share the same eyepiece objective 1305, it is possible to achieve clear fixation target visibility for different eyes.

[0071] (7) Measurement of axial length Since the detection depth of the OCT system is limited, it cannot achieve a single imaging detection from the cornea to the retina. Therefore, this embodiment combines anterior segment slit imaging and posterior segment OCT imaging technologies. The anterior segment slit imaging determines the position of the cornea of ​​the subject, and the posterior segment OCT imaging determines the position of the fundus of the subject, thereby realizing the measurement of the axial length.

[0072] like Figure 7 As shown, Er represents the fundus of the eye under test, Ec represents the corneal apex of the eye under test, X represents the change in optical path of the sample arm optical path caused by the optical path adjustment device (including fiber collimator 1107 and fiber head not shown in the figure) when measuring the posterior segment OCT image of the eye under test; CDK represents the spatial position corresponding to the top of the anterior segment slit image; RDK1 represents the spatial position corresponding to the top of the posterior segment OCT image when the optical path adjustment device is in the reset position; RDK2 represents the spatial position corresponding to the top of the posterior segment OCT image when the optical path adjustment device changes the change in optical path of the sample arm optical path X when measuring the posterior segment OCT image of the eye under test; hCornea represents the optical path from the top of the anterior segment slit image to the corneal apex Ec of the eye under test in the anterior segment slit image; hRetinal represents the optical path from the top of the posterior segment OCT image to the retinal signal in the posterior segment OCT image. Figure 7The three rectangles shown represent the posterior segment OCT measurement range. The rectangles are for illustrative purposes only, and the actual scanning area can be a fan-shaped structure or the like. The rectangle on the right represents the anterior segment slit image captured by anterior segment slit imaging.

[0073] When capturing images of the anterior segment fracture, the focusing position of the fracture light generated by the anterior segment fracture light source 1809 and the spatial position or range that the anterior segment fracture imaging optical path can capture are determined during system debugging. Figure 7 The spatial distance from the top of the anterior segment slit image to the eyepiece objective 1305 is determined during system debugging. Therefore, if the human eye under test moves slightly back and forth, but does not exceed the imaging range of the anterior segment slit, the spatial position of the cornea can be determined by identifying the corneal position captured in the anterior segment slit image.

[0074] When measuring OCT images of the posterior segment of the eye, since the axial length of the human eye varies, but the reference arm length of the OCT system is fixed, this embodiment uses the following methods to measure retinal depths at different depths: (a) by adding an optical path adjustment device to move the iso-interference plane of the posterior segment OCT imaging; (b) by translating the fiber collimator 1107 and the fiber optic head of the sample arm along the optical axis; (c) by adding a right-angle prism or a corner prism to cause multiple folds in the optical path, and then changing the optical path by translating the right-angle prism or corner prism. The above three methods can be used simultaneously, or one or two of them can be used.

[0075] The OCT system locates the retinal signal in the posterior segment of the eye. The change in optical path length of the optical path adjustment device relative to its reset position is X. That is, when the optical path length adjustment device changes the optical path distance of the sample arm by X, the spatial position corresponding to the top of the posterior segment OCT image moves from RDK1 to RDK2, where the distance between RDK1 and RDK2 is X. Figure 7 As shown.

[0076] The change in optical path X of the optical path adjustment device can be measured by various methods, such as using a stepper motor or voice coil motor to drive and calculate the movement; or using a grating ruler or capacitive grating ruler to calculate the movement, etc.

[0077] Furthermore, when the optical path adjustment device is in the reset position, the spatial distance between the spatial position RDK1 corresponding to the top of the posterior segment OCT image and the eyepiece objective 1305 is determined during system debugging. Therefore, the spatial distance ΔL between RDK1 (the spatial position corresponding to the top of the posterior segment OCT image) and CDK (the spatial position corresponding to the top of the anterior segment slit image) is determined during system debugging.

[0078] Therefore, by measuring the posterior segment OCT image and the anterior segment slit imaging, the axial length (Leye) of the human eye can be obtained. Leye=△L+X-hCornea+hRetinal, In the formula, hCornea can be measured from anterior segment slit images, while hRetinal can be measured from posterior segment OCT images.

[0079] Because the axial length of the eye varies among different individuals, it is necessary to change the optical path length of the sample arm or reference arm to measure the anterior and posterior segments (E) of the eye being measured, in order to achieve OCT coherent imaging (this embodiment uses changing the optical path length of the sample arm as an example). Changing the optical path length must also satisfy the detection depth of the OCT system and the different axial lengths of the eyes, requiring precise positioning, which often makes rapid switching to change the optical path length difficult. For example, using an optical path adjustment device that relies on the translation of a motor cannot achieve rapid switching to meet the optical path length requirements for measuring the anterior and posterior segments of the eye. Therefore, this embodiment uses a scheme combining anterior segment slit imaging and posterior segment OCT imaging to measure the axial length of the eye being measured.

[0080] Because anterior segment slit imaging and posterior segment OCT imaging use different imaging schemes (without requiring the OCT system to switch between anterior and posterior segment optical paths), they can acquire images simultaneously, thus avoiding the influence of eye movement and improving the measurement accuracy of axial length.

[0081] In this embodiment, corneal position is determined using anterior segment slit imaging, while fundus position is identified using posterior segment OCT imaging. Both techniques can operate and acquire images simultaneously without switching acquisition times, effectively avoiding the influence of eye movements and thus obtaining more accurate axial length data. Furthermore, acquiring anterior and posterior segment images in a single measurement facilitates doctor operation, improves diagnostic speed, and enhances the doctor-patient interaction experience. Additionally, a single measurement can detect numerous key human eye parameters, such as corneal diameter, anterior chamber depth, axial length, corneal curvature, and white-to-white contrast. This approach offers numerous advantages, including cost-effectiveness, speed, accuracy, and versatility.

[0082] Example 2 like Figure 8As shown, the ophthalmic optical biometry system disclosed in Embodiment 2 of the present invention differs from Embodiment 1 in that the anterior segment slit light source 1809 and the angle beam splitter 1807 are omitted in this embodiment. In this embodiment, light emitted from the OCT light source 1101 passes through the fiber optic coupler 1103 and the polarization controller 1105, and is then output through the fiber optic collimator 1107. The light beam is scanned by the optical path scanning device 1109, passes through the posterior segment OCT field lens 1301 and the anterior segment OCT insertion lens 1501, is reflected by the front beam splitter 1303, then transmitted through the eyepiece objective lens 1305, and finally converges onto the anterior segment of the eye to be tested. Due to the one-dimensional scanning of the optical path scanning device 1109, slit light is formed and incident on the eye to be tested. In this anterior segment OCT imaging system, the anterior segment slit light generated by the light source (OCT light source 1101) passes through the cornea, is scattered by the cornea, passes through the anterior segment slit imaging lens 1801, and is finally captured by the anterior segment slit imaging device 1803, thus forming an anterior segment slit image, such as... Figure 9 As shown.

[0083] Since the axial length of the human eye is often longer than the detection depth of an OCT system, switching from anterior segment OCT to posterior segment OCT often requires simultaneous adjustment of the optical path length of the OCT system's sample arm or reference arm. This ensures that the OCT probe light incident on the anterior segment of the eye meets the coherence length requirement with the reference arm, or vice versa. Therefore, OCT systems often need to switch and change the optical path length. For example, in Embodiment 1, the fiber collimator 1107 is connected to the sample arm fiber, and its entire structure is driven by a motor, allowing it to translate along its optical axis, thereby changing the optical path length of the sample arm. However, this method of changing the optical path length is slow due to the long travel distance (the axial length of the human eye) and the need to match the different axial lengths of different eyes. In Embodiment 1, however, simultaneous detection of anterior segment slit imaging and posterior segment OCT is used to measure the axial length, avoiding the influence of eye movements. In this second embodiment, to save on device costs, the anterior segment slit light source module uses an OCT light source module 1101 and an optical path scanning device 1109 to generate slit light to provide slit illumination. When measuring axial length, the switching between the posterior segment OCT imaging adjustment optical path unit and the anterior segment OCT imaging adjustment optical path unit is achieved by inserting or removing the anterior segment OCT insertion lens 1501; however, the axial length is still detected using anterior segment slit imaging combined with posterior segment OCT imaging, only the light source for anterior segment slit imaging is changed to the OCT light source 1101. Therefore, in this second embodiment, there is a brief switching time when measuring axial length—the insertion of the anterior segment OCT insertion lens 1501. However, since the insertion of the anterior segment OCT insertion lens 1501 only requires final positioning and does not require moving different distances for different axial lengths of the eyes as with optical path adjustment devices, the switching speed can be increased very quickly, for example, by using an electromagnet for switching.

[0084] In this embodiment, there is no need to add an anterior segment slit light source 1809 and an angle-beam splitter 1807. The existing OCT light source module 1101 and optical path scanning device 1109 are used to generate anterior segment slit illumination light, which is then focused on the anterior segment of the subject after passing through the anterior segment OCT imaging adjustment optical path unit. Compared with Embodiment 1, although the number of light source components is reduced, the switching from posterior segment OCT to anterior segment slit imaging requires the insertion of an anterior segment OCT insert lens 1501, resulting in a slight switching time. In addition, the one-dimensional scanning of the optical path scanning device 1109 to form slit light also requires a slight scanning time. However, since there is no need for a translational optical path adjustment device, the above time is faster than the solution in the prior art (e.g., the time required for the switching process between anterior and posterior segment OCT in prior art patent document 202011120798.5 includes the insertion of the anterior segment OCT insert lens and the time for the optical path adjustment device to change the optical path translation for the anterior and posterior segments of the subject's eye E), and it is easier to avoid the influence of eye movement when measuring the axial length for a long time.

[0085] Compared to Example 1, Example 2 does not require additional debugging of one optical path (anterior segment slit illumination optical path), thus reducing the difficulty of system debugging and increasing the system debugging speed.

[0086] In this second embodiment, the optical path of the OCT light source 1101 combined with the optical path scanning device 1109 is used to realize the function of the anterior segment slit light source without increasing hardware costs.

[0087] This embodiment differs from Embodiment 1 except for the anterior segment slit imaging module. It can be understood that the fixation optics module in this embodiment no longer includes the angle-beam splitter 1807. Figure 10 As shown, the other structures and principles are the same, and will not be described in detail here.

[0088] Example 3 like Figure 11 As shown, the ophthalmic optical biometry system disclosed in Embodiment 3 of the present invention, compared with Embodiment 2, does not use the OCT light source 1101 as the anterior segment slit light source in this embodiment. Instead, a wavelength division multiplexer 3807 couples the probe light input from the fiber coupler 1103 into the OCT sample arm with the light output from the anterior segment slit light source 3809 into the optical fiber 1106, and then exits through the sample arm fiber optic head (not shown in the figure). In this embodiment, the anterior segment slit light source module uses the anterior segment slit light source 3809, the wavelength division multiplexer 3807, the optical fiber 1106, and the optical path scanning device 1109 to generate slit light. The light output from the anterior segment slit light source 3809 is coupled by the wavelength division multiplexer 3807 and transmitted to the optical fiber 1106. The beam output from the optical fiber 1106 is scanned in one dimension by the optical path scanning device 1109 and then emits slit light, which passes through the anterior segment OCT imaging adjustment optical path unit and is focused on the anterior segment of the subject.

[0089] The 1106 fiber mentioned is not limited to single-mode fiber or multimode fiber. For example... Figure 12 As shown, the optical fiber 1106 has a core 11061, the outer layer of the core 11061 is the cladding 11063, and the sheath 11065 wraps around the cladding 11063, which serves to protect the optical fiber.

[0090] like Figure 13 As shown, the optical path for posterior segment OCT imaging in this embodiment differs from that in embodiment one only in that: light emitted from the OCT light source 1101 passes through the fiber coupler 1103, then through the polarization controller 1105, and then the probe light is transmitted to the wavelength division multiplexer 3807, and then transmitted through the fiber optic cable 1106 before being emitted.

[0091] like Figure 14 As shown, the difference between the anterior segment OCT imaging optical path in this embodiment and the anterior segment OCT imaging optical path in Embodiment 1 is only that: the light emitted from the OCT light source 1101 passes through the fiber coupler 1103, then through the polarization controller 1105, and then the probe light is transmitted to the wavelength division multiplexer 3807, and then transmitted through the fiber optic cable 1106 before being emitted.

[0092] like Figure 15 As shown, the anterior segment slit imaging optical path in this embodiment differs from that in Embodiment 2. In this embodiment, light is emitted from the anterior segment slit light source 3809, enters the optical fiber 1106 via a wavelength division multiplexer 3807, is transmitted through the optical fiber 1106, exits through the sample arm fiber optic head (not shown), and is then output through the fiber collimator 1107. The beam is scanned by the optical path scanning device 1109, passes through the posterior segment OCT field lens 1301 and the anterior segment OCT insertion lens 1501, is reflected by the front beam splitter 1303, then transmitted through the eyepiece objective lens 1305, and finally converges onto the anterior segment of the eye being tested. Due to the one-dimensional scanning of the optical path scanning device 1109, slit light is formed and incident on the eye being tested. In this anterior segment OCT imaging system, the light source (OCT light source 1101 and anterior segment slit light source 3809) generates anterior segment slit light that passes through the cornea, is scattered by the cornea, passes through the anterior segment slit imaging lens 1801, and is finally captured by the anterior segment slit imaging device 1803, thereby forming an anterior segment slit image.

[0093] When measuring axial length using the ophthalmic optical biometry system of this embodiment, similar to Embodiment 2, a relatively short switching scan time is required, and no translational optical path adjustment device is needed, thus the switching scan time is short. Additionally, wavelength division multiplexing 3807 couples the probe light input from the optical fiber coupler 1103 to the OCT sample arm with the light output from the anterior segment slit light source 3809 into the optical fiber 1106. Compared to Embodiment 2, the anterior segment slit light source 3809 can use a light source of a different wavelength band. Since the OCT light source 1101 generally uses near-infrared light, but the scattering coefficient of near-infrared light in the anterior segment tissue is relatively small. In this embodiment, the anterior segment slit light source 3809 can use a short-wavelength band to increase the scattering coefficient of the anterior segment tissue, such as the blue light band, thereby improving the anterior segment slit imaging effect.

[0094] Compared to Embodiment 1, this embodiment does not require additional debugging of one optical path (anterior segment slit illumination optical path), thus reducing the difficulty of system debugging and increasing the system debugging speed.

[0095] Example 4 like Figure 16 As shown, the ophthalmic optical biometry system disclosed in Embodiment 4 of the present invention, compared with Embodiment 3, in this embodiment, the probe light input from the optical fiber coupler 1103 to the OCT sample arm and the light output from the anterior segment slit light source 4809 enter the parallel optical fiber 2106, and then exit through the sample arm fiber optic head (not shown in the figure). In this embodiment, the anterior segment slit light source module uses the anterior segment slit light source 4809, the parallel optical fiber 2106, and the optical path scanning device 1109 to generate slit light. The light output from the anterior segment slit light source 4809 passes through the parallel optical fiber 2106, and the beam output from the parallel optical fiber 2106 is scanned in one dimension by the optical path scanning device 1109, emitting slit light, and then passes through the anterior segment OCT imaging adjustment optical path unit and is focused on the anterior segment of the subject.

[0096] like Figure 17As shown, the parallel optical fiber 2106 has an OCT optical path core 21061 and an anterior segment slit illumination optical path core 21062. The OCT optical path core 21061 is used to transmit the probe light input from the optical fiber coupler 1103 into the OCT sample arm, and the OCT optical path core 21061 is wrapped by the OCT optical path cladding 21063. The anterior segment slit illumination optical path core 21062 is used to transmit the light output from the anterior segment slit light source 4809, and the anterior segment slit illumination optical path core 21062 is wrapped by the anterior segment slit illumination fiber cladding 21064. The OCT optical path cladding 21063 and the anterior segment slit illumination fiber cladding 21064 are arranged in parallel and are wrapped together by a sheath 21065. Parallel optical fibers 2106 share a single fiber optic connector (not shown in the figure). The probe light from the OCT sample arm and the light output from the anterior segment slit light source 4809 of the transmission line are input from the fiber coupler 1103, and after passing through the fiber optic connector, they enter the optical path of the OCT sample arm module. This shared fiber optic connector forms two light-emitting sources, and the distance between these two sources is the distance d between the OCT optical path fiber core 21061 and the anterior segment slit illumination optical path fiber core 21062. A smaller distance d is better. When d is small, the parallel optical fibers 2106, sharing a single sample arm fiber optic connector, can emit light from approximately one light-emitting point. After passing through the optical path of the OCT sample arm module 130, the distance between the two probe points when incident on the eye under test will also be smaller.

[0097] Compared to traditional dual-core fiber 3106 (such as...) Figure 18 As shown in the diagram, fiber cores 31061 / 31062 are wrapped by fiber cladding 31063 / 31064, then by sheaths 31065 / 31066, and finally by a large sheath 31069. In this configuration, the spacing d3 between the two fiber cores is often quite large. Consequently, the light emitted from the two fiber cores 31061 / 31062 cannot be approximated by a single emission point. Therefore, when the light enters the eye of the person being tested after passing through the optical path of the OCT sample arm module 130, the distance between the two detection points will also be relatively large.

[0098] Therefore, the optical path for OCT imaging of the posterior segment and the optical path for OCT imaging of the anterior segment in this embodiment are similar to those in Embodiment 1 or Embodiment 2. The only difference is that the probe light input from the optical fiber coupler 1103 into the OCT optical path core 21061 in the parallel optical fiber 2106, and then exits through the optical fiber head of the sample arm (not shown in the figure).

[0099] like Figure 19As shown, in this embodiment, compared to Embodiment 2, the light emitted from the anterior segment slit imaging optical path enters the parallel optical fiber 2106 from the anterior segment slit light source 4809, is transmitted through the anterior segment slit illumination optical path fiber core 21062, and then exits through the common fiber head (not shown in the figure), before being output through the fiber collimator 1107. The beam is scanned by the optical path scanning device 1109, passes through the posterior segment OCT field lens 1301 and the anterior segment OCT insertion lens 1501, is reflected by the front beam splitter 1303, then transmitted through the eyepiece objective lens 1305, and finally converges onto the anterior segment of the eye being tested. Due to the one-dimensional scanning of the optical path scanning device 1109, slit light is formed and incident on the eye being tested. In this anterior segment OCT imaging system, the light source (OCT light source 1101) and the anterior segment slit light source 4809 generate anterior segment slit light that passes through the cornea, is scattered by the cornea, passes through the anterior segment slit imaging lens 1801, and is finally captured by the anterior segment slit imaging device 1803, thereby forming an anterior segment slit image.

[0100] When measuring axial length using the ophthalmic optical biometry system of this embodiment, similar to Embodiments 2 and 3, a relatively short switching scan time is required, and no translational optical path adjustment device is needed, thus the switching scan time is short. Additionally, the probe light input from the fiber coupler 1103 to the OCT sample arm and the light output from the anterior segment slit light source 4809 are fed in parallel into the parallel optical fiber 2106. Compared to Embodiment 2, the anterior segment slit light source 4809 can use a light source of a different wavelength band. Since the OCT light source 1101 generally uses near-infrared light, but the scattering coefficient of near-infrared light in the anterior segment tissue is relatively small, in Embodiments 3 and 4, the anterior segment slit light source 3809 or the anterior segment slit light source 4809 can use a short-wavelength band to increase the scattering coefficient of the anterior segment tissue, such as the blue light band, thereby improving the anterior segment slit imaging effect.

[0101] Example 5 refer to Figures 20-21 The anterior segment camera module 190 and fixation optical module of the ophthalmic optical biometry system disclosed in Embodiment 5 of the present invention are the same as those in Embodiment 2.

[0102] Posterior segment OCT sample arm module: The posterior segment OCT sample arm module includes an optical path scanning device 1109 and a posterior segment OCT imaging adjustment optical path unit; Compared with Embodiment 1 or Embodiment 2, the light emitted from the fiber collimator 1107 first passes through the beam splitter 5805 and is then reflected by the optical path scanning device 1109.

[0103] Anterior segment slit imaging: The anterior segment slit imaging adjustment optical path module adopts the aforementioned posterior segment OCT imaging adjustment optical path unit. Compared to the anterior segment slit imaging optical path in Embodiments 3 and 4, in Embodiment 5, the anterior segment slit light source module includes anterior segment slit light source 5809, lens 5807, and beam splitter 5805. Light emitted from the anterior segment slit light source 5809 passes through lens 5807, is reflected by beam splitter 5805, and then reflected by optical path scanning device 1109. It then passes through posterior segment OCT imaging adjustment optical path unit (passes through posterior segment OCT field lens 1301, is reflected by front beam splitter 1303, and then transmitted through eyepiece objective lens 1305), finally converging on the anterior segment of the eye. Due to the one-dimensional scanning of optical path scanning device 1109, slit light is formed and incident on the eye under test. The anterior segment slit light generated by the anterior segment slit light source 5809 passes through the cornea, is scattered by the cornea, passes through the anterior segment slit imaging lens 1801, and is finally captured by the anterior segment slit imaging device 1803, thereby forming an anterior segment slit image. The lens 5807 in this embodiment plays a similar role to the anterior segment OCT insertion lens 1501 in the aforementioned embodiment.

[0104] In this embodiment, the anterior segment slit light generation optical path utilizes an optical path scanning device 1109 (eliminating the need for an additional scanning mechanism) to perform scanning, thereby simplifying the generation of slit light. This allows for greater freedom in the arrangement of the optical path, as seen in the anterior segment slit light source 1809 in Embodiment 1. In other embodiments, if the optical path scanning device 1109 is not used, the anterior segment slit light source 5809 needs to emit slit light, also known as narrow beam light. In this case, a knife-edge mechanical structure needs to be added to the light source to obtain a very sharp line light source.

[0105] Compared to Example 1, Examples 2, 3, and 4 do not require additional debugging of one optical path (anterior segment slit illumination optical path), thus reducing the difficulty of system debugging and increasing the system debugging speed.

[0106] Compared to Example 3, Example 4 does not require the addition of wavelength division multiplexer 3807, but the parallel optical fiber 2106 is not a traditional optical fiber and requires special processing and fabrication.

[0107] In Examples 3 and 4, the probe light of the OCT sample arm is coupled with or output in parallel with the slit light of the anterior segment, and then they enter the optical path of the optical path scanning device 1109 and the optical path of the anterior segment OCT imaging adjustment optical path unit together. This allows the two optical paths to be basically parallel, which greatly reduces the difficulty of debugging the two optical paths.

[0108] In Example 5, when measuring axial length, the same as in Examples 3 and 4, the light source can be switched electronically. Only a short scanning time is required, eliminating the need for a translational optical path adjustment device. Furthermore, the anterior segment slit image and posterior segment OCT imaging can be acquired simultaneously, effectively avoiding the influence of eye movements and thus improving the real-time performance and accuracy of axial length measurement.

[0109] The ophthalmic optical biometry system designed in this invention has two main advantages: First, it enables measurement of objects at different depths, improving the detection range of the OCT system (anterior and posterior segment imaging), ensuring stable switching, precise positioning, and no impact on the system's signal-to-noise ratio. Second, it allows for beam focusing at different positions, enabling high-quality OCT imaging of different eye regions for individuals with varying vision, and possesses high lateral resolution. The anterior and posterior segment imaging OCT system can acquire numerous parameters of the human eye, such as corneal curvature, corneal thickness, anterior chamber depth, lens thickness, lens surface curvature, white-to-white distance, and pupil diameter. Combining anterior segment imaging and automatic recognition technology assists in automated instrument detection. Through iris recognition technology, automatic recognition of anterior segment OCT images, and automatic recognition of posterior segment OCT images, the system achieves fully automated detection. Simultaneously with posterior segment OCT image acquisition, anterior segment slit imaging is performed to obtain accurate axial length data. The ophthalmic optical biometry system and method for measuring axial length proposed in this invention have the following characteristics: (a) The probe optical path is required to achieve OCT imaging of different parts of the human eye under test, but the focusing positions used are different, so the optical path used for measurement should be different. When performing OCT imaging of the posterior segment of the eye, the OCT beam is required to be parallel to the human eye (for emmetropic eyes); while when performing OCT imaging of the anterior segment of the eye, the OCT beam is required to be focused on the anterior segment of the eye. This design is beneficial to improving the imaging quality of the anterior and posterior segments of OCT.

[0110] (b) When performing OCT imaging of the posterior segment of the eye, the optical path plane is located on the retina of the subject's eye, while when performing OCT imaging of the anterior segment of the eye, the optical path plane is located on the anterior segment of the subject's eye. Therefore, it is not necessary to adjust the optical path of the reference arm to achieve OCT imaging of different parts.

[0111] (c) It can perform refractive compensation for people with different vision and realize imaging of different parts of the human eye.

[0112] (d) It can realize the fixation optical path of the human eye to satisfy the fixation of the left and right eyes.

[0113] (e) The anterior segment camera optical path, combined with automatic iris recognition technology, can be used to control the movement of the probe module, thereby enabling the detection of the subject's eye. The obtained iris image can be used to measure parameters such as pupil diameter and white-to-white distance.

[0114] (f) A fast and accurate switching device enables rapid OCT imaging of different parts of the human eye.

[0115] (g) Based on OCT imaging of different parts of the human eye, it can achieve rapid and accurate measurement of axial length, anterior chamber depth, lens thickness, etc., without moving the reference arm.

[0116] (h) Rapid switching between front and rear sections, fewer moving parts, and low cost.

[0117] (i) The fixation optical path and the posterior segment OCT share the same refractive adjustment device, which reduces the moving parts of the fixation optical path and realizes the cofocality of the fixation optical path and the posterior segment OCT optical path, which is beneficial to the fixation of the subject's eye and the acquisition of posterior segment OCT images.

[0118] (j) Precise localization of the cornea is obtained through anterior segment slit imaging.

[0119] (k) Frequency domain optical coherence tomography (FCO) technology has a faster scanning speed and higher imaging resolution than time domain systems, but a shallower detection depth. Compared with frequency domain optical coherence tomography, it has comparable scanning speed and resolution, but a much lower cost, and a shallower detection depth.

[0120] (l) Low-cost, rapid switching scanning scheme to achieve anterior and posterior segment OCT imaging. Combining anterior segment imaging and automatic recognition technology, automatic detection of the subject eye is achieved. In addition, in principle, optical coherence tomography (OCT) technology is used, which is theoretically an unlimited frequency domain, frequency sweep, and even time domain system.

[0121] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, several equivalent substitutions or obvious modifications can be made without departing from the concept of the present invention, and all such modifications, achieving the same performance or purpose, should be considered within the scope of protection of the present invention.

Claims

1. An optical system for measuring axial length of the eye, characterized in that, It includes an OCT light source module, an OCT imaging module, a posterior segment OCT sample arm module, and an anterior segment slit imaging component, among which: The OCT light source module is used to provide measurement light. The measurement light passes through the posterior segment OCT sample arm module and is incident on the fundus of the subject's eye. The OCT imaging module receives the measurement light returned from the fundus of the subject's eye to obtain an OCT image of the posterior segment. The anterior segment slit imaging component includes an anterior segment slit light source module, an anterior segment slit imaging module, and an anterior segment slit imaging adjustment optical path module. The anterior segment slit light source module is used to provide slit light. The slit light passes through the anterior segment slit imaging adjustment optical path module and is focused on the anterior segment of the subject. The anterior segment slit imaging module receives the returned slit light to obtain an anterior segment slit image. Using the posterior segment OCT image and the anterior segment slit image, first optical path data and second optical path data are obtained respectively, and the axial length is calculated using the first optical path data and the second optical path data; The posterior segment OCT sample arm module includes an optical path scanning device (1109) and a posterior segment OCT imaging adjustment optical path unit. The anterior segment slit imaging adjustment optical path module adopts the posterior segment OCT imaging adjustment optical path unit.

2. The optical system according to claim 1, characterized in that, The anterior segment slit imaging module includes an anterior segment slit imaging lens (1801) and an anterior segment slit imaging device (1803). The slit light emitted by the anterior segment slit light source module is focused on the anterior segment of the subject and returns to the anterior segment slit light signal. The signal passes through the anterior segment slit imaging lens (1801) and is received by the anterior segment slit imaging device (1803). The anterior segment slit imaging device (1803) obtains an anterior segment slit image based on the anterior segment slit light signal.

3. The optical system according to claim 2, characterized in that, The anterior segment slit imaging adjustment optical path module includes an eyepiece objective (1305), which is located on the optical path in a first direction, wherein the optical path in the first direction is perpendicular to the human eye under test, and the anterior segment slit imaging lens (1801) and the anterior segment slit imaging device (1803) are respectively disposed below the eyepiece objective (1305).

4. The optical system according to claim 1, characterized in that, The anterior segment slit light source module includes anterior segment slit light source (5809), lens (5807) and beam splitter (5805). The anterior segment slit light source (5809) emits light, which passes through the lens (5807), is reflected by the beam splitter (5805), and is then scanned in one dimension by the optical path scanning device (1109) to form slit light. After passing through the anterior segment slit imaging adjustment optical path module, the light is focused on the anterior segment of the subject.

5. The optical system according to claim 4, characterized in that, The posterior segment OCT imaging adjustment optical path unit includes a posterior segment OCT field lens (1301), a front beam splitter (1303), and an eyepiece objective (1305). The measurement light provided by the OCT light source module is reflected by the optical path scanning device (1109), passes through the posterior segment OCT field lens (1301), and is then reflected by the front beam splitter (1303) to the eyepiece objective (1305). After passing through the eye of the subject, the light converges to the fundus of the subject's eye, and the light signal is returned to the posterior segment and transmitted to the OCT imaging module. The OCT imaging module acquires a posterior segment OCT image based on the posterior segment light signal. The anterior segment OCT imaging adjustment optical path unit is formed by inserting an anterior segment OCT insertion lens (1501) into the optical path formed by the posterior segment OCT imaging adjustment optical path unit. After the slit light passes through the posterior segment OCT field lens (1301), it is reflected by the front beam splitter (1303) to the eyepiece objective lens (1305) and converges on the anterior segment of the subject to be tested, so as to return the anterior segment slit light signal to the anterior segment slit imaging module. The anterior segment slit imaging module acquires the anterior segment slit image based on the anterior segment slit light signal.

6. The optical system according to claim 1, characterized in that, The first optical path data refers to the optical path hRetinal from the top of the posterior segment OCT image to the retinal signal in the posterior segment OCT image, which is measured based on the posterior segment OCT image of the eye under test. The second optical path data refers to the optical path hCornea from the top of the anterior segment slit image to the corneal apex of the eye under test, which is measured based on the anterior segment slit image of the eye under test. The axial length of the eye is calculated using the first optical path data and the second optical path data, including: calculating the axial length Leye of the eye under test based on the optical path change X of the posterior segment OCT sample arm module when acquiring the OCT image of the posterior segment of the eye under test, as well as the measured optical path hRetinal and optical path hCornea.

7. A method for measuring axial length, characterized in that, Measuring the axial length of the human eye under test using the optical system according to any one of claims 1 to 6 includes the following steps: Acquire an OCT image of the posterior segment of the eye of the subject to be tested, and measure the optical path hRetinal from the top of the posterior segment OCT image to the retinal signal in the posterior segment OCT image based on the OCT image of the posterior segment of the eye of the subject to be tested. Acquire an anterior segment slit image of the eye under test, and measure the optical path hCornea from the top of the anterior segment slit image to the corneal apex of the eye under test based on the anterior segment slit image of the eye under test. The axial length Leye of the human eye under test is calculated based on the optical path change X of the posterior segment OCT sample arm module when acquiring the OCT image of the posterior segment of the human eye under test, as well as the measured optical path hRetinal and optical path hCornea.

8. The method according to claim 7, characterized in that, The axial length (Leye) of the human eye being tested is calculated using the following formula: Leye=△L+X-hCornea+hRetinal; Where △L represents the spatial distance between the top of the posterior segment OCT image and the top of the anterior segment slit image, and X represents the change in optical path of the posterior segment OCT sample arm module when acquiring the posterior segment OCT image of the human eye under test.

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