An ophthalmic measurement system based on a frequency loading device

Abstract

This invention provides an ophthalmic measurement system based on a frequency-adjusting device, comprising an OCT light source, a reference arm, a sample arm module, an optical fiber coupler, and a detector. The sample arm module integrates an optical path switching scanning device, capable of reflecting the probe light to the posterior or anterior segment of the eye. By introducing a frequency-adjusting device to dynamically adjust the optical path, maintaining a constant optical path or phase change between the A and Scan, Doppler frequency shift is achieved, enhancing detection depth without sacrificing resolution. The system can rapidly switch imaging focal points to adapt to eyes with different vision and perform refractive compensation, acquiring high-resolution OCT images. Furthermore, the system can accurately measure key parameters such as corneal curvature, thickness, anterior chamber depth, and lens thickness, effectively improving diagnostic speed. This invention overcomes the limitations of existing technologies in detection depth, imaging speed, and accuracy while ensuring image quality.

Description

Technical Field

[0001] This invention relates to ophthalmic optical coherence tomography, and in particular to an ophthalmic measurement system based on a frequency loading device. Background Technology

[0002] 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 placement requires numerous parameters, such as the curvature of the anterior and posterior corneal surfaces, corneal thickness, anterior chamber depth, lens thickness, the curvature of the anterior and posterior lens surfaces, and axial length. 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 of measurement for patients but also enhance its accuracy.

[0003] With the in-depth development of ophthalmological research, the medical community has discovered a significant correlation between myopia in adolescents and the increase in their axial length. Rapid increase in axial length during adolescent growth and development is often accompanied by a rapid progression of myopia. Therefore, studying and tracking changes in axial length growth is one of the important indicators among ophthalmological parameters in myopia prevention and control for adolescents.

[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] 1) Existing technologies for measuring axial length often employ time-domain tomographic scanning, which is slow and has low measurement accuracy.

[0006] Patent document 200710020707.9 discloses a method for measuring axial length of the eye using OCT. While this method can measure the axial length of the human eye and various live animals, it has two drawbacks: 1. It uses a stepper motor to move the probe to adjust the optical path, thereby achieving imaging of the cornea and fundus. However, the forward and backward movement of the motor takes time, making it impossible to achieve rapid switching between the anterior and posterior segments and real-time imaging. Furthermore, the subject's eye may shake, leading to inaccurate axial length measurements with significant errors; 2. Due to the different structures of the cornea and fundus, the same probe cannot focus at both locations, resulting in poor image quality. This is an unavoidable defect of this method.

[0007] 2) The existing patent "An OCT system and method for measuring axial length and optical path value, application number 201410214827.2" introduces corneal alignment technology, eliminating the need to switch between the anterior and posterior segments, but it lacks anterior segment measurement function and corneal curvature measurement function (or does not mention them). Measuring the cornea requires an additional operation. This prevents rapid diagnosis for patients.

[0008] 3) Existing patents “Ophthalmic Measurement System and Method, Application No. 201810130278.9” and “Ophthalmic Measurement System, Application No. 201910116857.2” make it difficult to increase the detection depth of the OCT system.

[0009] 4) The existing patent "Ophthalmic Measurement System Based on Shutter Switching, Application No. 202020735955.2" measures the anterior chamber depth and lens thickness. It also uses OCT data after two switching of the optical path to calculate the axial length. This switching speed will affect the measurement accuracy of the anterior chamber depth and lens thickness.

[0010] Compared to time-domain OCT systems, frequency-domain optical coherence tomography (OCT) offers faster scanning speed and higher imaging resolution, but shallower detection depth. Compared to frequency-domain OCT, it offers comparable scanning speed and resolution at a much lower cost, but still has a shallower detection depth.

[0011] It should be noted that the information disclosed in the background section above is only for understanding the background of this application, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0012] The main objective of this invention is to overcome the deficiencies in the aforementioned background technology and provide an ophthalmic measurement system based on a frequency loading device.

[0013] To achieve the above objectives, the present invention adopts the following technical solution:

[0014] An ophthalmic measurement system based on a frequency loading device includes an OCT imaging module. The OCT imaging module includes an OCT light source, a reference arm module, an OCT sample arm module, an optical fiber coupler, and a detector. The OCT sample arm module includes an optical path switching scanning device, a posterior segment OCT sample arm optical path, and an anterior segment OCT sample arm optical path. The probe light output from the optical fiber coupler is reflected at different angles by the optical path switching scanning device and then enters the posterior segment OCT sample arm optical path or the anterior segment OCT sample arm optical path accordingly. The system also includes a frequency loading device for changing the optical path during OCT scanning and maintaining a constant optical path or phase change between adjacent OCT scans (A-Scan), introducing a Doppler frequency shift to the probe light.

[0015] Furthermore, the frequency loading device includes a motor and a flat glass plate. The motor drives the flat glass plate to deflect or rotate to dynamically adjust the optical path. The optical path switching scanning device adjusts its scanning angle during the scanning process to cooperate with the deflection or rotation of the flat glass plate, working together to act on the probe light and maintain a constant optical path or phase change between adjacent OCT scans (A-Scan).

[0016] Furthermore, the motor drives the flat glass to deflect to a set angle, so that after the probe light passes through the flat glass, it will not hit the rotation center of the rotating reflector of the optical path switching scanning device. By utilizing the scanning angle change of the optical path switching scanning device during the scanning process, the optical path or phase change between adjacent OCT scans A-Scan is kept constant.

[0017] Furthermore, the motor drives the flat glass to rotate, scanning synchronously with the optical path switching scanning device to generate varying optical paths, while maintaining a constant optical path or phase change between adjacent OCT scans (A-Scan).

[0018] Furthermore, the frequency loading device includes a servo mechanism, and the OCT sample arm module includes a sample arm fiber optic head and a fiber optic collimator. The probe light enters the optical path switching scanning device from the sample arm fiber optic head through the fiber optic collimator. The servo mechanism drives the fiber optic collimator and the sample arm fiber optic head, causing them to move together as a whole, changing the optical path length of the sample arm. This, in conjunction with the optical path switching scanning device, ensures that the optical path or phase change between adjacent OCT scans (A-Scan) remains constant.

[0019] Furthermore, the frequency loading device includes a servo mechanism, and the reference arm module includes a reference arm fiber optic head, a reference arm optical path lens, and a reference arm reflector. The reference light passes from the reference arm fiber optic head, through the reference arm optical path lens, strikes the reference arm reflector, and is then reflected by the reference arm reflector back into the fiber coupler. The servo mechanism drives the reference arm optical path lens and the reference arm fiber optic head, causing them to move together as a whole, changing the optical path length of the reference arm. This, in conjunction with the optical path switching scanning device, ensures that the optical path or phase change between adjacent OCT scans (A-Scan) remains constant.

[0020] Furthermore, the optical path of the anterior segment OCT sample arm includes an anterior chamber insertion lens, which is configured to cut into or out of the optical path; the anterior chamber insertion lens is designed to cut into the optical path during anterior chamber OCT scanning imaging to guide the probe beam to focus near the center of the anterior chamber; during full-lens panoramic OCT scanning imaging, the anterior chamber insertion lens is in the cut-out state.

[0021] Furthermore, the optical path of the anterior segment OCT sample arm includes a first reflecting mirror, a first lens, a third reflecting mirror, a fifth reflecting mirror, a third lens, a third beam splitter, a front beam splitter, and an eyepiece objective. After being reflected by the optical path switching scanning device, the light beam is successively reflected by the first reflecting mirror, transmitted through the first lens, reflected by the third reflecting mirror and the fifth reflecting mirror, transmitted through the third lens, transmitted through the third beam splitter, reflected by the front beam splitter to the eyepiece objective, and finally converged to the anterior segment of the eye by the human eye. The anterior chamber insertion lens can be inserted into the optical path of the anterior segment OCT sample arm.

[0022] Furthermore, the optical path of the posterior segment OCT sample arm sequentially includes a light path adjustment module, a posterior segment and fixation beam splitter, a refractive adjustment device, a third beam splitter, a front beam splitter, and an eye-connecting objective lens. After being reflected by the optical path switching scanning device, the light beam passes through the light path adjustment module, then through the posterior segment and fixation beam splitter, passes through the refractive adjustment device, is reflected by the third beam splitter, then by the front beam splitter to the eye-connecting objective lens, and finally converges to the fundus of the human eye.

[0023] Furthermore, it also includes a computer connected to the detector, which processes the interference signal that introduces Doppler frequency shift and uses a de-mirroring algorithm to obtain an OCT image using positive and negative frequency image data.

[0024] The present invention has the following beneficial effects:

[0025] This invention's ophthalmic measurement system achieves efficient and accurate imaging of different parts of the eye by rapidly switching between anterior and posterior segment OCT imaging systems and combining Doppler frequency shift technology. The system employs an optical path switching scanning device that reflects probe light at different angles, directing it into the OCT sample arm optical path of the posterior or anterior segment. A frequency-adjusting device dynamically adjusts the optical path, maintaining a constant optical path or phase change between adjacent OCT scans (A-Scans), introducing Doppler frequency shift to increase the system's detection depth without reducing detection resolution. This design not only improves the detection range and stability of the OCT system but also ensures accurate positioning without affecting the system's signal-to-noise ratio. Furthermore, the system can perform refractive compensation for eyes with different vision levels, achieving high-quality imaging of different parts of the eye with high lateral resolution. Through rapid and precise optical path switching, the system can achieve rapid OCT imaging of different parts of the eye and accurately measure key ophthalmic parameters such as corneal curvature, corneal thickness, anterior chamber depth, and lens thickness, meeting the needs of clinical diagnosis. This invention effectively overcomes the problems of limited detection depth, slow imaging speed and low measurement accuracy in the prior art, and provides an ophthalmic measurement system that can quickly and accurately acquire multiple optical parameters of the human eye.

[0026] Other beneficial effects of the embodiments of the present invention will be further described below. Attached Figure Description

[0027] Figure 1 This is the optical path diagram of the OCT system in Embodiment 1 of the present invention.

[0028] Figure 2 This is a diagram of the posterior segment OCT imaging system of Embodiment 1 of the present invention.

[0029] Figure 3 This is a diagram of the anterior segment OCT imaging system of Embodiment 1 of the present invention.

[0030] Figure 4 This is the optical path diagram of the OCT system in Embodiment 2 of the present invention.

[0031] Figure 5 This is the optical path diagram of the OCT system in Embodiment 3 of the present invention.

[0032] Figure 6 This is a diagram of the anterior segment OCT imaging system of Embodiment 3 of the present invention. Detailed Implementation

[0033] The embodiments of the present invention will be described in detail below. It should be emphasized that the following description is merely exemplary and is not intended to limit the scope and application of the present invention.

[0034] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as "connected to" another component, it can be directly connected to or indirectly connected to that other component. Furthermore, a connection can be used for fixing, coupling, or communication.

[0035] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" 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.

[0036] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of the present invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0037] See Figures 1 to 6 This invention provides an ophthalmic measurement system based on a frequency loading device, including an OCT imaging module. The OCT imaging module includes an OCT light source 1101, a reference arm module, an OCT sample arm module, an optical fiber coupler 1103, and a detector 1141. The OCT sample arm module includes an optical path switching scanning device 1109, a posterior segment OCT sample arm optical path, and an anterior segment OCT sample arm optical path. The probe light output by the optical fiber coupler 1103 is reflected at different angles by the optical path switching scanning device 1109 and then enters the posterior segment OCT sample arm optical path or the anterior segment OCT sample arm optical path accordingly. The system also includes a frequency loading device, which is used to change the optical path during OCT scanning and keep the optical path or phase change between adjacent OCT scans constant, introducing a Doppler frequency shift to the probe light.

[0038] See Figures 1 to 3 , Figure 5 and Figure 6 In some embodiments, the frequency loading device includes a motor 1203 and a flat glass plate 1201. The motor 1203 drives the flat glass plate 1201 to deflect or rotate to dynamically adjust the optical path. The optical path switching scanning device 1109 adjusts its scanning angle during the scanning process to cooperate with the deflection or rotation of the flat glass plate 1201, working together to act on the probe light and maintain a constant optical path or phase change between adjacent OCT scans A-Scan. In one embodiment, the motor 1203 drives the flat glass plate 1201 to deflect to a set angle, so that after the probe light passes through the flat glass plate 1201, it will not hit the rotation center of the rotating reflective surface of the optical path switching scanning device 1109. The optical path switching scanning device 1109 maintains a constant optical path or phase change between adjacent OCT scans A-Scan by utilizing the scanning angle change of the optical path switching scanning device 1109 during the scanning process. In another embodiment, the motor 1203 drives the flat glass 1201 to rotate, scanning synchronously with the optical path switching scanning device 1109 to generate varying optical path lengths while maintaining constant optical path lengths or phase changes between adjacent OCT scans (A-Scan). The motor 1203 can be a servo motor 1203 suitable for driving a galvanometer system.

[0039] See Figure 4In some embodiments, the frequency loading device includes a servo mechanism 2205, and the OCT sample arm module includes a sample arm fiber optic head and a fiber collimating lens 1107. The probe light enters the optical path switching scanning device 1109 from the sample arm fiber optic head through the fiber collimating lens 1107. The servo mechanism drives the fiber collimating lens 1107 and the sample arm fiber optic head to move together as a whole, changing the optical path length of the sample arm. This, in conjunction with the optical path switching scanning device 1109, allows scanning to be performed, keeping the optical path or phase change between adjacent OCT scans constant.

[0040] In some embodiments, the frequency loading device includes a servo mechanism (not shown), and the reference arm module includes a reference arm fiber optic head, a reference arm optical path lens 1121, and a reference arm reflector 1123. The reference light passes from the reference arm fiber optic head, through the reference arm optical path lens 1121, strikes the reference arm reflector 1123, and is then reflected by the reference arm reflector 1123 and returns to the fiber coupler 1103. The servo mechanism drives the reference arm optical path lens 1121 and the reference arm fiber optic head to move together as a whole, changing the optical path length of the reference arm. This, in conjunction with the optical path switching scanning device 1109, performs scanning, ensuring that the optical path or phase change between adjacent OCT scans (A-Scan) remains constant.

[0041] This invention presents a rapid switching OCT imaging system for anterior and posterior segments, combining a scanning device and Doppler frequency shift technology. On one hand, it features rapid switching, enabling measurements at different depths of an object, thus increasing the detection range of the OCT system (anterior and posterior segment OCT imaging). The switching system is stable, precise, and does not affect the system's signal-to-noise ratio. On the other hand, it allows for separate beam focusing at different positions, enabling high-quality OCT imaging of different parts of the eye for individuals with varying vision, achieving high lateral resolution. This rapid switching OCT system can acquire numerous parameters of the human eye, such as corneal curvature, corneal thickness, anterior chamber depth, lens thickness, lens surface curvature, axial length, white-to-white diameter, and pupil diameter. It can focus separately on tissues at different depths of the eye: the anterior chamber, lens, and retina, thereby improving the signal-to-noise ratio and resolution of OCT detection in different tissues. The combination of Doppler frequency shift technology, or frequency loading technology, increases the system's detection depth while maintaining the same detection resolution. This invention effectively solves the problem of shallow detection depth in frequency domain systems, which cannot measure anterior chamber depth or lens thickness in a single measurement.

[0042] The OCT imaging system of this invention employs different scanning modes and focusing positions to achieve OCT imaging of different parts of the human eye, resulting in varying optical paths for measuring different eye regions. During fundus OCT imaging, the scanning beam's centerline converges at the pupil, and the OCT beam must be parallel to the eye at any given time. In anterior segment imaging, the OCT beam must be focused on tissues at different depths within the anterior segment at any given time. This invention allows for refractive compensation for eyes with varying vision, enabling imaging of different eye regions. It allows the probe beam to be focused on different areas when measuring different parts of the anterior segment, improving imaging resolution and signal-to-noise ratio. A rapid and precise optical path switching scanning device enables fast OCT imaging of different eye regions. Based on OCT imaging of different eye regions, this invention can achieve rapid and accurate measurements of axial length, anterior chamber depth, and lens thickness.

[0043] This invention presents a rapid switching OCT imaging system for different segments of the eye, combining a scanning device and Doppler frequency shift technology. Through innovative optical path design and control mechanisms, it achieves efficient and accurate imaging of different parts of the eye. This OCT imaging system not only enables rapid switching imaging of different parts of the eye but also utilizes Doppler frequency shift technology to increase the system's detection depth while maintaining constant detection resolution, effectively overcoming the limitations of traditional frequency domain systems in terms of detection depth.

[0044] The following describes specific embodiments of the present invention.

[0045] Example 1

[0046] The optical path diagram of the OCT system in Example 1 is as follows: Figure 1 As shown.

[0047] The ophthalmic measurement system based on the loading frequency device is a rapid switching OCT imaging system that combines a scanning device and Doppler frequency shift technology. It includes: an OCT imaging module, a posterior segment OCT sample arm module, an anterior segment OCT sample arm module, a fixation optics module (not shown), and an anterior segment camera module (not shown), and a loading frequency device.

[0048] The optical path is switched by computer-controlled optical path switching scanning device 1109 and frequency loading device, realizing OCT imaging of different depth parts of the human eye.

[0049] OCT imaging module

[0050] The OCT imaging module includes an OCT light source 1101, an optical fiber coupler 1103, a reference arm module, a detector 1141, a computer 1143, and a sample arm module.

[0051] The reference arm module includes a reference arm optical path lens 1121 and a reference arm reflector 1123.

[0052] The sample arm module includes a polarization controller 1105, an optical fiber collimator 1107, an optical path switching scanning device 1109, a posterior segment OCT sample arm module, and an anterior segment OCT sample arm module.

[0053] In this embodiment, the frequency loading device is located between the fiber optic collimating lens 1107 and the optical path switching scanning device 1109. This frequency loading device consists of a flat glass plate 1201 and a motor 1203. The motor 1203 drives the flat glass plate 1201 to deflect, thereby changing the optical path or shifting the optical path to achieve a Doppler frequency shift effect, i.e., frequency loading. In other embodiments, the frequency loading device can also be located in the reference arm module, for example, between the reference arm optical path lens 1121 and the reference arm reflector 1123.

[0054] The optical path of the OCT imaging module includes a weakly coherent light source 1101, whose output light is supplied to the sample arm module and reference arm module via fiber optic coupler 1103. The reference arm module has a known length and reflects the light back to the fiber optic coupler 1103 via a reference arm reflector 1123. The sample arm module provides light to the subject's eye E. The light scattered from the sample interferes with the light reflected from the reference arm via the sample arm, polarization controller 1105, and the reference arm 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 sample. The sample is scanned by an optical path switching scanning device 1109 to achieve OCT tomographic imaging.

[0055] The OCT light source 1101 outputs near-infrared light.

[0056] Posterior segment OCT sample arm module

[0057] The posterior segment OCT imaging system of Example 1 is as follows: Figure 2 As shown.

[0058] The posterior segment sample arm module 130 includes an optical path switching scanning device 1109, an optical path adjustment module 1301, a posterior segment and fixation beam splitter 1303 (first beam splitter 1303), a refractive adjustment device 1305, a third beam splitter 1307, a front beam splitter 1309 (fifth beam splitter 1309), and an eyepiece objective lens 1311. In this embodiment, the posterior segment sample arm module 130 also includes a flat glass plate 1201.

[0059] During posterior segment OCT imaging, light emitted from the fiber optic collimator 1107 passes through the flat glass 1201 and is reflected by the optical path switching scanning device 1109. The optical path switching scanning device 1109 is controlled by the computer 1143. After reflection by the optical path switching scanning device 1109, the beam passes through the optical path adjustment module 1301, then through the posterior segment and the fixation beam splitter 1303 (first beam splitter 1303), passes through the refractive adjustment device 1305, is reflected by the third beam splitter 1307, and then by the front beam splitter 1309 (fifth beam splitter 1309) to the eyepiece objective lens 1311. Finally, it converges at the fundus Er of the human eye. 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 human eye, and the OCT beam is focused on the fundus Er of the human eye at any given time.

[0060] The optical path switching scanning device 1109, controlled by the computer 1143, is positioned to achieve OCT imaging of the posterior segment of the eye. At this time, the position of the optical path switching scanning device 1109 ensures that the angle between the principal axis of the incident light from the fiber optic collimator 1107 and the principal axis of the reflected light is α. The fundus OCT imaging optical path refractive adjustment device 1305, tailored to different human eyes (with varying refractive powers), ensures that the OCT beam is focused on the retina (Er) of the human eye. This effectively improves the signal-to-noise ratio and lateral resolution of the OCT image during retinal measurements.

[0061] The optical path switching scanning device 1109 not only performs scanning but also optical path switching. This invention utilizes a galvanometer or other high-precision positioning mechanism to meet the system's requirements for rapid optical path switching and scanning. When measuring the fundus, the optical path switching scanning device 1109 rotates, causing the main optical axis to be reflected from the fiber collimator 1107 to the optical path adjustment module 1301, thus changing the main optical axis of the beam by angle α (as shown in the figure above). When measuring the anterior segment, rotating the optical path switching scanning device 1109 causes the main optical axis to be reflected from the fiber collimator 1107 to the first reflecting mirror 1501, thus changing the main optical axis of the beam by angle β (as shown in the figure below). The optical path switching scanning device 1109, in conjunction with the third beam splitter 1307, enables the switching of the optical paths between the anterior and posterior segments.

[0062] The optical path adjustment module 1301 can be constructed using a cornerstone prism, a right-angle prism, or two mutually perpendicular total reflection mirrors. The optical path is changed by moving it up and down as shown in the figure.

[0063] The optical path switching scanning device 1109 can be a one-dimensional optical path switching scanning device, or it can be two-dimensional or even three-dimensional.

[0064] Anterior segment OCT sample arm module

[0065] The anterior segment OCT imaging system of Example 1 is as follows: Figure 3 As shown.

[0066] The anterior segment sample arm module includes an optical path switching scanning device 1109, a first reflecting mirror 1501, a first lens 1503, a third reflecting mirror 1505, a fifth reflecting mirror 1507, a third lens 1509, a third beam splitter 1307, a front beam splitter 1309 (fifth beam splitter 1309), and an eyepiece objective lens 1311. In this embodiment, the anterior segment sample arm module also includes a flat glass plate 1201.

[0067] During anterior segment OCT imaging, light emitted from the fiber optic collimator 1107 passes through the flat glass 1201 and is reflected by the optical path switching scanning device 1109. At this time, the optical path switching scanning device 1109 is controlled by the computer 1143. After being reflected by the optical path switching scanning device 1109, the beam is successively reflected by the first reflecting mirror 1501, transmitted through the first lens 1503, reflected by the third reflecting mirror 1505 and the fifth reflecting mirror 1507, transmitted through the third lens 1509, transmitted through the third beam splitter 1307, and then reflected by the front beam splitter 1309 (the fifth beam splitter 1309) to the eyepiece objective 1311, finally converging on the anterior segment of the eye E. The detection 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.

[0068] The optical path switching scanning device 1109 is controlled by the computer 1143 and is positioned to realize anterior segment OCT imaging. At this time, the position of the optical path switching scanning device 1109 is such that the angle between the principal axis of the incident light from the fiber collimating lens 1107 and the principal axis of the reflected light is β.

[0069] In this embodiment, the detection depth of the OCT system is achieved through frequency shifting technology, also known as Doppler frequency shifting technology, in conjunction with the scanning of the optical path switching scanning device 1109. This ensures that the optical path or phase change between adjacent OCT scans (A-Scan) remains constant, thereby eliminating mirror images and increasing the OCT detection depth. The OCT system's detection depth can achieve a single-image detection from the cornea to the posterior surface of the lens (the tissue depth from the cornea to the posterior surface of the lens is approximately 8 mm), but it is insufficient to achieve a single-image OCT image from the cornea to the retina (Note: the average axial length of the human eye from the cornea to the retina is approximately 24 mm (tissue depth)). While increasing the detection depth of the OCT system could also be achieved by using scanning frequency domain OCT or frequency domain spectrometer technology with even greater detection depth, the cost of scanning frequency domain OCT or frequency domain spectrometer technology with greater detection depth is often higher. Furthermore, frequency domain spectrometer technology with greater detection depth often requires doubling the pixel count of its linear array camera, further amplifying the cost increase. The frequency loading technology in this embodiment achieves the goal of doubling the detection depth while ensuring the same imaging resolution and image quality, with only a limited increase in cost.

[0070] The frequency loading technique can be implemented in several ways. For example, by using a motor 1203 to deflect the flat glass 1201 to a specific angle, the sample arm probe light emitted from the fiber optic collimator 1107 is deflected by the flat glass 1201, and the light spot does not hit the rotation center of the rotating reflector of the optical path switching scanning device 1109. As the optical path switching scanning device 1109 rotates at high speed, the sample arm probe light is introduced with a Doppler frequency shift. The computer 1143 processes the interference signal that introduces the Doppler frequency shift and, through an OCT de-mirror algorithm, obtains an OCT image utilizing positive and negative frequency image data, thereby doubling the detection depth. This method of using a motor 1203 to deflect the flat glass 1201 to a specific angle can be easily achieved using an electromagnet or a motor mechanical structure, thus reducing costs.

[0071] Another approach involves rotating the flat glass 1201 via a motor 1203, simultaneously scanning with the optical path switching scanning device 1109. This ensures that the optical path length or phase change between adjacent OCT scans (A-Scans) remains constant after the sample arm probe light emitted from the fiber optic collimating lens 1107 passes through the flat glass 1201. The OCT signal obtained using this method is equivalent to introducing a Doppler frequency shift. The computer 1143 processes the OCT signal obtained by this scanning method and, through a de-mirrorization algorithm, obtains an OCT image utilizing both positive and negative frequency image data, thereby doubling the detection depth. In this approach, the rotation of the flat glass 1201 by the motor 1203 requires simultaneous scanning with the optical path switching scanning device 1109, and the maintenance of a constant optical path length or phase change between adjacent OCT scans (A-Scans). Therefore, the accuracy and speed requirements for the deflection angle corresponding to each A-Scan of the flat glass 1201 are high, necessitating the use of a servo mechanism such as a galvanometer for the motor 1203 to achieve rapid rotation and positioning.

[0072] Summary of the main modules and their functions in this embodiment: 1) Posterior segment OCT sample arm module, which can obtain important parameters of eye structure such as retinal thickness; 2) Anterior segment OCT sample arm module, which can obtain OCT images of the anterior and posterior surfaces of the cornea and lens, thereby obtaining important parameters of eye structure 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; 3) The anterior segment OCT sample arm module, in conjunction with the posterior segment OCT sample arm module, can obtain important parameters of eye structure such as axial length; 4) In this embodiment 1, anterior and posterior segment OCT images can be obtained by rapidly switching between anterior and posterior segment scanning imaging.

[0073] Summary of main working principles:

[0074] 1) During the anterior segment OCT detection, Doppler frequency shift technology is used and an algorithm is used to remove the image to increase the detection depth of the OCT system. Combined with the posterior segment OCT, the axial length of the eye is measured.

[0075] 2) By rapidly switching scans, corneal and retinal OCT images are measured to determine axial length. Then, frequency or optical path adjustment is applied to achieve anterior segment panoramic OCT measurement, followed by lens panoramic measurement.

[0076] Example 2

[0077] The optical path of the OCT system in Example 2 is as follows: Figure 4 As shown.

[0078] Compared to Example 1, Example 2 omits the flat glass 1201 and motor 1203. Instead, a servo mechanism 2205 drives the fiber collimating lens 1107 and the sample arm fiber optic head (not shown), causing them to move as a whole. The servo mechanism 2205 changes the optical path length of the sample arm through translation, cooperating with the optical path switching scanning device 1109 to perform scanning, ensuring that the optical path or phase change between adjacent OCT scans (A-Scan) remains constant. The OCT signal obtained by this method is equivalent to introducing a Doppler frequency shift. The computer 1143 processes the OCT signal obtained by this scanning method and, through a de-mirror algorithm, obtains an OCT image utilizing positive and negative frequency image data, thereby achieving the goal of doubling the detection depth.

[0079] Similarly, the servo mechanism 2205 can also be mounted in the reference arm, driving the reference arm optical path lens 1121 and the reference arm fiber optic head (not shown), so that the two move together as a whole. The servo mechanism 2205 changes the optical path length of the sample arm through translation, cooperating with the optical path switching scanning device 1109 to perform scanning, ensuring that the optical path or phase change between adjacent OCT scans (A-Scan) remains constant. The OCT signal obtained by this method is equivalent to introducing a Doppler frequency shift.

[0080] The servo mechanism 2205 can be a mechanical device that can achieve rapid translation, such as a voice coil motor or piezoelectric ceramic.

[0081] Example 3

[0082] The optical path of the OCT system in Example 3 is as follows: Figure 5 As shown.

[0083] Compared to Example 1, Example 3 introduces an OCT sample arm module for the anterior segment of the eye, which incorporates OCT imaging shutter devices for different depths of the anterior segment (hereinafter referred to as shutter devices). Optical path switching is achieved through computer-controlled optical path switching scanning device 1109 and the OCT imaging shutter devices for different depths of the anterior segment, enabling OCT imaging of different depths of the human eye.

[0084] In this embodiment 3, the posterior segment sample arm module 130 remains unchanged.

[0085] Anterior segment OCT sample arm module

[0086] The anterior segment OCT imaging system of Example 3 is as follows: Figure 6 As shown.

[0087] The anterior segment sample arm module includes an optical path switching scanning device 1109, a first reflecting mirror 1501, a first lens 1503, a third reflecting mirror 1505, a fifth reflecting mirror 1507, a third lens 1509, a third beam splitter 1307, a front beam splitter 1309 (fifth beam splitter 1309), and an eyepiece objective lens 1311. The anterior segment sample arm module also includes an anterior chamber insertion lens 3601 and a flat glass plate 1201.

[0088] In this embodiment 3, the anterior segment OCT sample arm module can be used for panoramic OCT scanning imaging of the entire lens and OCT scanning imaging of the anterior chamber.

[0089] Panoramic OCT imaging of the entire lens

[0090] When performing a full-lens panoramic OCT scan, the light emitted from the fiber optic collimator 1107 passes through the flat glass 1201 and is reflected by the optical path switching scanning device 1109. At this time, the optical path switching scanning device 1109 is controlled by the computer 1143. After being reflected by the optical path switching scanning device 1109, the light beam is successively reflected by the first reflecting mirror 1501, transmitted through the first lens 1503, reflected by the third reflecting mirror 1505 and the fifth reflecting mirror 1507, transmitted through the third lens 1509, transmitted through the third beam splitter 1307, and then reflected by the front beam splitter 1309 (the fifth beam splitter 1309) to the eyepiece objective lens 1311. Finally, it converges to the lens of the human eye through the eye E. The detection beam of the anterior segment OCT imaging optical path system satisfies the requirement that the OCT beam is focused onto the lens of the human eye.

[0091] The optical path switching scanning device 1109 is controlled by the computer 1143 and is positioned to realize anterior segment OCT imaging. At this time, the position of the optical path switching scanning device 1109 is such that the angle between the principal axis of the incident light from the fiber collimating lens 1107 and the principal axis of the reflected light is β.

[0092] In this embodiment, the anterior segment sample arm module is preferentially used for panoramic OCT scanning imaging of the entire lens. At this time, the insert mirror of the OCT imaging shutter device for different depths of the anterior segment—the anterior chamber insertion mirror 3601—is in a state of being away from the anterior segment OCT optical path. That is, when measuring panoramic OCT scanning imaging of the entire lens, the probe light does not pass through the insert mirror of the shutter device.

[0093] OCT imaging of the anterior chamber

[0094] When performing anterior chamber OCT scanning imaging, the optical path of the anterior segment OCT sample arm also includes an optical path switching scanning device 1109, a first reflecting mirror 1501, a first lens 1503, a third reflecting mirror 1505, an anterior chamber insertion mirror 3601 of the shutter device, a fifth reflecting mirror 1507, a third lens 1509, a third beam splitter 1307, a front beam splitter 1309 (fifth beam splitter 1309), an eyepiece objective lens 1311, and a flat glass plate 1201.

[0095] During anterior chamber OCT scanning imaging, the light emitted from the fiber optic collimator 1107 passes through the flat glass 1201 and is reflected by the optical path switching scanning device 1109, which is controlled by the computer 1143. After being reflected by the optical path switching scanning device 1109, the beam is successively reflected by the first reflecting mirror 1501, transmitted through the first lens 1503, then through the third reflecting mirror 1505, through the anterior chamber insertion mirror 3601, reflected by the fifth reflecting mirror 1507, transmitted through the third lens 1509, transmitted through the third beam splitter 1307, and then reflected by the front beam splitter 1309 (the fifth beam splitter 1309) to the eyepiece objective lens 1311. Finally, it converges near the center of the anterior chamber of the eye through the human eye E. The detection beam of the anterior chamber OCT scanning imaging optical path system satisfies the requirement that the OCT beam is focused near the center of the anterior chamber of the eye.

[0096] The optical path switching scanning device 1109 is controlled by the computer 1143 and is positioned to realize anterior segment OCT imaging. At this time, the position of the optical path switching scanning device 1109 is such that the angle between the principal axis of the incident light from the fiber collimating lens 1107 and the principal axis of the reflected light is β.

[0097] At this time, the anterior chamber insertion mirror 3601 of the shutter device is inserted into the anterior segment OCT optical path. That is, during anterior chamber OCT scanning and imaging, the probe light passes through the anterior chamber insertion mirror 3601. Therefore, the anterior chamber insertion mirror 3601 not only adjusts the optical path but also changes the focusing position of the anterior segment OCT sample arm optical path. Its insertion position is only shown in the figure; in principle, it can be inserted into other positions in the anterior segment OCT sample arm optical path.

[0098] Compared to Example 1, its OCT system can detect at a shallower depth and at a lower cost. Through frequency loading technology, it can detect the area from the cornea to the anterior surface of the lens, i.e., the anterior chamber, and can also achieve OCT imaging of the entire lens. However, it cannot achieve a single OCT scan imaging from the cornea to the posterior surface of the lens.

[0099] In Example 3, the OCT system can achieve OCT scanning imaging of the entire anterior chamber and posterior segment of the eye by rapidly switching the optical path of the anterior and posterior segment OCT sample arm modules. After the subject has obtained the OCT images of the anterior chamber and posterior segment, the system probe does not need to be moved or repositioned. By switching out the anterior chamber insertion lens 3601, OCT scanning imaging of the lens of the eye under test can be achieved.

[0100] In summary, the present invention provides an ophthalmic measurement system, and its main advantages compared with the prior art are:

[0101] The ophthalmic measurement system of this invention achieves rapid switching and scanning of the anterior and posterior segment optical paths through the coordinated operation of a frequency-shifting device (Doppler frequency shifting device) and a scanning device. This allows the system to acquire anterior and posterior segment OCT images and parameters such as optical path adjustment, thereby measuring multiple optical parameters of the human eye. By introducing Doppler frequency shifting technology through the frequency-shifting device, the detection depth of the frequency domain OCT system is enhanced. Simultaneously, cost control and signal-to-noise ratio are rationally allocated within a limited budget, improving image quality.

[0102] Furthermore, the system enables rapid scanning of both anterior and posterior segments through quick switching, achieving near real-time scanning speeds and acquiring dozens of images per second. This rapid scanning speed helps reduce the impact of irregular eye movements, thus accurately measuring the axial length of the eye. A single measurement process can acquire images of both anterior and posterior segments, which not only facilitates the doctor's operation but also improves diagnostic speed and the doctor-patient interaction experience. Simultaneously, the system can detect key parameters such as corneal diameter, anterior chamber depth, axial length, and corneal curvature in a single measurement.

[0103] The system of this invention can meet the measurement needs of different parts of the eye, obtain accurate data on important parameters of the human eye, and meet the needs of clinical diagnosis. It can be used to measure optical parameters related to the patient's eye, guide the selection of intraocular lens parameters, conduct eye examinations, and guide myopia prevention and control in adolescents. The system can measure key ophthalmic parameters such as axial length, corneal curvature and thickness, anterior chamber depth, and lens thickness. By combining rapid switching between the anterior and posterior segments and Doppler frequency shift technology, this invention achieves panoramic anterior segment OCT scanning, enabling the measurement of axial length, anterior chamber depth, lens thickness, and corneal thickness, ultimately achieving comprehensive measurement of the optical parameters of the human eye.

[0104] In summary, this invention has significant advantages in terms of cost, speed, accuracy, and versatility.

[0105] The above description provides a further detailed explanation of the present invention in conjunction with specific / preferred embodiments, and it should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various substitutions or modifications can be made to these described embodiments without departing from the concept of the present invention, and all such substitutions or modifications should be considered within the scope of protection of the present invention. In the description of this specification, the reference to terms such as "an embodiment," "some embodiments," "preferred embodiment," "example," "specific example," or "some examples," etc., indicates that the specific features, structures, materials, or characteristics described in connection with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples. Without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification and the features of different embodiments or examples. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions, and modifications can be made herein without departing from the scope of protection of the patent application.

Claims

1. An ophthalmic measurement system based on a frequency loading device, comprising an OCT imaging module, the OCT imaging module including an OCT light source, a reference arm module, an OCT sample arm module, an optical fiber coupler, and a detector, the OCT sample arm module including an optical path switching scanning device, a posterior segment OCT sample arm optical path, and an anterior segment OCT sample arm optical path, wherein the probe light output from the optical fiber coupler is reflected at different angles by the optical path switching scanning device and then enters the posterior segment OCT sample arm optical path or the anterior segment OCT sample arm optical path accordingly; characterized in that, It also includes a frequency loading device, which is used to change the optical path during OCT scanning and keep the optical path or phase change constant between adjacent OCT scans A-Scan, and introduce a Doppler frequency shift to the probe light.

2. The ophthalmic measurement system as described in claim 1, characterized in that, The frequency loading device includes a motor and a flat glass plate. The motor drives the flat glass plate to deflect or rotate to dynamically adjust the optical path. The optical path switching scanning device adjusts its scanning angle during the scanning process to cooperate with the deflection or rotation of the flat glass plate, working together to act on the detection light and keep the optical path or phase change between adjacent OCT scans constant.

3. The ophthalmic measurement system as described in claim 2, characterized in that, The motor drives the flat glass to deflect to a set angle, so that the probe light will not hit the rotation center of the rotating reflector of the optical path switching scanning device after passing through the flat glass. By utilizing the scanning angle change of the optical path switching scanning device during the scanning process, the optical path or phase change between adjacent OCT scans A-Scan is kept constant.

4. The ophthalmic measurement system as described in claim 2, characterized in that, The motor drives the flat glass to rotate, scanning synchronously with the optical path switching scanning device to generate varying optical paths and maintain constant optical path or phase changes between adjacent OCT scans (A-Scan).

5. The ophthalmic measurement system as described in claim 1, characterized in that, The frequency loading device includes a servo mechanism, and the OCT sample arm module includes a sample arm fiber optic head and a fiber optic collimator. The probe light enters the optical path switching scanning device from the sample arm fiber optic head through the fiber optic collimator. The servo mechanism drives the fiber optic collimator and the sample arm fiber optic head to move together as a whole, changing the optical path length of the sample arm. This, in conjunction with the optical path switching scanning device, ensures that the optical path or phase change between adjacent OCT scans (A-Scan) remains constant.

6. The ophthalmic measurement system as described in claim 1, characterized in that, The frequency loading device includes a servo mechanism, and the reference arm module includes a reference arm fiber optic head, a reference arm optical path lens, and a reference arm reflector. Reference light passes from the reference arm fiber optic head, through the reference arm optical path lens, strikes the reference arm reflector, is reflected by the reference arm reflector, and returns to the fiber coupler. The servo mechanism drives the reference arm optical path lens and the reference arm fiber optic head, causing them to move together as a whole, changing the optical path length of the reference arm. This, in conjunction with the optical path switching scanning device, ensures that the optical path or phase change between adjacent OCT scans (A-Scan) remains constant.

7. The ophthalmic measurement system according to any one of claims 1 to 6, characterized in that, The optical path of the anterior segment OCT sample arm includes an anterior chamber insertion lens, which is configured to cut into or out of the optical path; the anterior chamber insertion lens is designed to cut into the optical path during anterior chamber OCT scanning imaging to guide the probe beam to focus near the center of the anterior chamber; during full-lens panoramic OCT scanning imaging, the anterior chamber insertion lens is in the cut-out state.

8. The ophthalmic measurement system as described in claim 7, characterized in that, The optical path of the anterior segment OCT sample arm includes a first reflecting mirror, a first lens, a third reflecting mirror, a fifth reflecting mirror, a third lens, a third beam splitter, a front beam splitter, and an eyepiece objective. After being reflected by the optical path switching scanning device, the light beam is successively reflected by the first reflecting mirror, transmitted through the first lens, reflected by the third reflecting mirror and the fifth reflecting mirror, transmitted through the third lens, transmitted through the third beam splitter, reflected by the front beam splitter, and then reflected to the eyepiece objective. Finally, it converges to the anterior segment of the eye. The anterior chamber insertion lens can be inserted into the optical path of the anterior segment OCT sample arm.

9. The ophthalmic measurement system according to any one of claims 1 to 8, characterized in that, The optical path of the posterior segment OCT sample arm includes, in sequence, a light path adjustment module, a posterior segment and fixation beam splitter, a refractive adjustment device, a third beam splitter, a front beam splitter, and an eye-connecting objective lens. After being reflected by the optical path switching scanning device, the light beam passes through the light path adjustment module, then through the posterior segment and fixation beam splitter, passes through the refractive adjustment device, is reflected by the third beam splitter, then by the front beam splitter to the eye-connecting objective lens, and finally converges to the fundus of the human eye.

10. The ophthalmic measurement system according to any one of claims 1 to 9, characterized in that, It also includes a computer connected to the detector, which processes the interference signal that introduces Doppler frequency shift and uses a de-mirroring algorithm to obtain an OCT image using positive and negative frequency image data.

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