Ophthalmology measurement system with double-optical-wedge prism group

Abstract

The utility model provides an ophthalmology measuring system with a double-optical-wedge prism group, which realizes efficient and accurate ophthalmology OCT (optical coherence tomography) imaging. The system comprises an OCT imaging module which comprises an OCT light source, a reference arm module, an OCT sample arm module, an optical fiber coupler and a detector. The sample arm module is integrated with an optical path switching scanning device and can guide detection light to a posterior segment or anterior segment optical path. A double-optical-wedge prism group is introduced and comprises a fixed prism and a movable prism, and the movable prism can translate relative to the fixed prism to dynamically adjust the optical path. The design is combined with the Doppler frequency shift technology, the detection depth of the system is remarkably enhanced, meanwhile, the imaging resolution is kept, and high-cost equipment does not need to be additionally added. The system can rapidly switch imaging modes, realizes accurate imaging of different parts of the eyes, improves the measurement speed and accuracy, reduces the cost, and is suitable for clinical ophthalmic diagnosis.

Description

TECHNICAL FIELD

[0001] The utility model relates to ophthalmic measuring equipment especially to an ophthalmic measuring system with double optical wedge prism group. BACKGROUND

[0002] Nowadays, the number of the elderly suffering from cataract eye diseases is increasing, and the implantation of artificial lens is an effective solution for treating cataract. However, the calculation of artificial lens requires many parameters, such as corneal anterior and posterior surface curvature, corneal thickness, anterior chamber depth, lens thickness, lens anterior and posterior surface curvature, and eye axial length. Many parameters need to be measured, but the complete data can be obtained only after detection by multiple medical devices. Therefore, if a device can obtain the above data, it can improve the convenience and accuracy of measurement for patients.

[0003] With the in-depth research and development of ophthalmology, the medical community has found that the myopia problem of adolescents has a great correlation with the growth of their eye axial length. During the growth and development of adolescents, the rapid growth of the eye axial length is often accompanied by rapid deepening of myopia. Therefore, when preventing and controlling adolescent myopia, researching and tracking the growth and change of the eye axial length of adolescents is also one of the important indicators in their ophthalmic parameters.

[0004] Optical coherence tomography (OCT) is a new optical imaging technology. Compared with traditional clinical imaging methods, it has the advantages of high resolution, fast imaging speed, no radiation damage, moderate price, and compact structure, and is an important potential tool for basic medical research and clinical diagnosis. Currently, in various ophthalmic devices using optical instruments, OCT devices for ophthalmic examination and treatment have become indispensable ophthalmic devices for the diagnosis of ophthalmic diseases.

[0005] 1) The existing technology for measuring axial length often uses time-domain tomographic scanning technology, which is slow and has low measurement accuracy.

[0006] Patent document 200710020707.9 discloses a method for measuring eye axial length using OCT. This method can measure the eye axial length of human eyes and various animal living bodies, but it has the following two shortcomings: 1. A moving probe using a stepping motor is used to adjust the optical path, thereby realizing imaging of the cornea and the fundus. However, the motor needs a certain time to move forward and backward, which cannot realize fast switching between the anterior and posterior segments and real-time imaging. In addition, the eyes of the measured object will shake, which makes the measurement of the eye axial length inaccurate and has a large error; 2. Due to the different structures of the cornea and the fundus, the same probe cannot be focused at both positions, which leads to poor imaging quality. This is an unavoidable defect of this method.

[0007] 2) The existing patent "OCT system and method for measuring ocular axial optical path value, application number 201410214827.2" introduces corneal position alignment technology, without switching the anterior and posterior segments, but without anterior segment measurement function and corneal curvature measurement function (or not mentioned). The measurement of the cornea needs to be operated once more. It cannot realize the rapid diagnosis of patients.

[0008] 3) The existing patents "ophthalmic measurement system and method, application number 201810130278.9" and "ophthalmic measurement system, application number 201910116857.2", the detection depth of the OCT system is difficult to deepen.

[0009] 4) The existing patent "ophthalmic measurement system based on shutter switching, application number 202020735955.2", which measures the anterior chamber depth and lens thickness, also uses the OCT data after the light path is switched twice to cooperate with the calculation of the axial length. This switching speed will affect the measurement accuracy of the anterior chamber depth and the lens thickness.

[0010] Using frequency domain optical coherence tomography technology, compared with time domain OCT system, the scanning imaging speed is fast, the imaging resolution is high, but the detection depth is shallow; compared with scanning frequency domain optical coherence tomography technology, the scanning speed, resolution and the like are equivalent, and the cost is much lower, but the detection depth is shallow.

[0011] It should be noted that the information disclosed in the above background section is only for understanding the background of the present application, and therefore can include information that does not constitute prior art known to those of ordinary skill in the art. Content of the utility model

[0012] The main purpose of the utility model is to overcome the defects in the above background technology, and provide an ophthalmic measurement system with a double optical wedge prism group.

[0013] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0014] An ophthalmic measurement system with a dual-wedge prism group, comprising an OCT imaging module, the OCT imaging module comprising an OCT light source, a reference arm module, an OCT sample arm module, a fiber coupler and a detector, the OCT sample arm module comprising an optical path switching scanning device, an ocular posterior OCT sample arm optical path and an ocular anterior OCT sample arm optical path, the detection light output from the fiber coupler is reflected by the optical path switching scanning device at different angles and enters the ocular posterior OCT sample arm optical path or the ocular anterior OCT sample arm optical path accordingly; further comprising a dual-wedge prism group, the dual-wedge prism group is arranged in the reference arm module or the OCT sample arm module, the dual-wedge prism group comprises a fixed prism and a movable prism, the movable prism can move horizontally relative to the fixed prism to change the optical path length.

[0015] Further, the movable prism is connected to a prism driving motor, and the movable prism is driven by the prism driving motor.

[0016] Further, the reference arm module comprises a reference arm optical path lens and a reference arm mirror, the dual-wedge prism group is arranged between the reference arm optical path lens and the reference arm mirror, the reference light from the fiber coupler passes through the reference arm optical path lens and the dual-wedge prism group and hits the reference arm mirror, and then is reflected by the reference arm mirror and returns to the fiber coupler.

[0017] Further, the dual-wedge prism group is arranged between a fiber collimator and the optical path switching scanning device, and the detection light from the fiber coupler passes through the fiber collimator and the dual-wedge prism group and then enters the optical path switching scanning device.

[0018] Further, the driving of the prism is a voice coil motor or a piezoelectric ceramic device.

[0019] Further, the ocular anterior OCT sample arm optical path comprises a first mirror, a first lens, a third mirror, a fifth mirror, a third lens, a third beam splitter, a pre-beam splitter and an objective lens, the light beam is reflected by the optical path switching scanning device, and then is reflected by the first mirror, transmitted by the first lens, reflected by the third mirror and the fifth mirror, transmitted by the third lens, transmitted by the third beam splitter, reflected by the pre-beam splitter and then enters the objective lens, and finally converges on the ocular anterior of the human eye.

[0020] Further, the posterior ocular segment OCT sample arm optical path comprises, in sequence, an optical path adjusting module, a posterior ocular segment and fixation beam splitter, a refractive adjustment device, a third beam splitter, a front beam splitter and an ocular objective lens, after the light beam is reflected by the optical path switching scanning device, passes through the optical path adjusting module, is reflected by the posterior ocular segment and fixation beam splitter, passes through the refractive adjustment device, is reflected by the third beam splitter, is reflected by the front beam splitter to the ocular objective lens, and finally converges to the fundus of the human eye through the human eye.

[0021] The utility model has the following beneficial effects:

[0022] The ophthalmic measurement system of the utility model realizes the significant technical improvement of ophthalmic OCT imaging through the innovative design of introducing the double wedge prism group. The system combines the scanning device and the Doppler frequency shift technology, allows fast switching of the anterior and posterior segment OCT imaging, thereby efficiently and accurately imaging different parts of the eye. The introduction of the double wedge prism group effectively simulates the Doppler frequency shift effect by changing the optical path of the light path, deepens the detection depth of the system, while maintaining the imaging resolution unchanged. This design not only improves the detection depth of the OCT system, but also avoids using the more expensive scanning frequency domain OCT or the deeper depth frequency domain spectrometer technology. In addition, while ensuring high imaging quality and resolution, the system doubles the detection depth at a limited cost, effectively solves the limitations of traditional frequency domain systems in detection depth, and provides an imaging solution with high cost-effectiveness, simple operation and accurate measurement for ophthalmic clinical diagnosis.

[0023] Other beneficial effects of the embodiments of the utility model will be further described below. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The OCT system optical path diagram of the embodiments of the utility model. DETAILED DESCRIPTION

[0025] The embodiments of the utility model will be described in detail below. It should be emphasized that the following description is only exemplary and is not intended to limit the scope of the utility model and its applications.

[0026] It should be noted that when an element is referred to as being "fixed" or "disposed" on another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. In addition, the connection can be for fixing or for coupling or communicating.

[0027] It should be understood that the terms "length", "width", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of the utility model and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the utility model.

[0028] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the embodiments of the utility model, the meaning of "multiple" is two or more, unless otherwise explicitly specified.

[0029] Referring to Figure 1 , the utility model embodiment provides a kind of ophthalmic measurement system with double optical wedge prism group, including OCT imaging module, the OCT imaging module includes OCT light source 1101, reference arm module, OCT sample arm module, fiber coupler 1103 and detector 1141, the OCT sample arm module includes optical path switching scanning device 1109, eye posterior segment OCT sample arm optical path and anterior segment OCT sample arm optical path, probe light output by the fiber coupler 1103 is reflected by the optical path switching scanning device 1109 at different angles, and correspondingly enter the eye posterior segment OCT sample arm optical path or the anterior segment OCT sample arm optical path;It also includes double optical wedge prism group, the double optical wedge prism group is configured in the reference arm module or the OCT sample arm module, the double optical wedge prism group includes fixed prism and movable prism, the movable prism can be parallelly moved relative to fixed prism, to change the optical path optical path.

[0030] As Figure 1 Shown, in some embodiments, the reference arm module includes reference arm optical path lens 1121 and reference arm mirror 1123, the double optical wedge prism group is arranged between the reference arm optical path lens 1121 and the reference arm mirror 1123, and reference light is reflected on the reference arm mirror 1123 after passing through the reference arm optical path lens 1121 and the double optical wedge prism group from the fiber coupler 1103, and then returns into the fiber coupler 1103.

[0031] In other embodiments, the dual optical wedge prism group can be arranged between the fiber collimator 1107 and the optical path switching scanning device 1109, and the probe light enters the optical path switching scanning device 1109 after passing through the fiber collimator 1107 and the dual optical wedge prism group from the fiber coupler 1103.

[0032] In some embodiments, the prism driving motor can be a voice coil motor or a piezoelectric ceramic device.

[0033] The ophthalmic measurement system with a dual optical wedge prism group of the utility model discloses a fast switching anterior and posterior segment OCT imaging system combined with scanning device and Doppler frequency shift technology, and through the innovative optical path design and control mechanism, efficient and accurate imaging of different parts of the eye can be realized. Not only can the fast switching imaging of different parts of the eye be realized, but also the Doppler frequency shift technology can be combined to deepen the detection depth of the system while keeping the detection resolution unchanged, effectively solving the limitation of the traditional frequency domain system in the detection depth.

[0034] The utility model specific embodiments are further described below.

[0035] As Figure 1 The ophthalmic measurement system with a dual optical wedge prism group is a fast switching anterior and posterior segment OCT imaging system combined with scanning device and Doppler frequency shift technology, which comprises: an OCT imaging module, an ocular posterior segment OCT sample arm module, an ocular anterior segment OCT sample arm module, a fixation optical module (not shown), an ocular anterior segment camera module (not shown) and a dual optical wedge prism group.

[0036] The optical path switching is realized by computer control of the optical path switching scanning device 1109 and the dual optical wedge prism group, and the OCT imaging of different depth parts of the human eye is realized.

[0037] OCT imaging module

[0038] The OCT imaging module comprises an OCT light source 1101, a fiber coupler 1103, a reference arm module, a detector 1141, a computer 1143 and a sample arm module.

[0039] The reference arm module comprises a reference arm optical path lens 1121 and a reference arm mirror 1123.

[0040] The sample arm module comprises a polarization controller 1105, a fiber collimator 1107, an optical path switching scanning device 1109, an ocular posterior segment OCT sample arm module and an ocular anterior segment OCT sample arm module.

[0041] The OCT imaging module light path includes a weak coherent light source 1101, the light output of which provides light to the sample arm module and the reference arm module through the fiber coupler 1103. The reference arm module has a known length and reflects the light back into the fiber coupler 1103 through the reference arm mirror 1123. The sample arm module provides light to the eye E to be examined, the light scattered back from the sample passes through the sample arm, the polarization controller 1105, and the light reflected back from the reference arm interferes in the fiber coupler 1103, the interference light is detected by the detector 1141, processed by the computer 1143, and finally the OCT image of the sample being measured is displayed. The sample is scanned by the light path switching scanning device 1109 to achieve the tomographic imaging of OCT.

[0042] The OCT light source 1101 outputs near-infrared light.

[0043] The OCT imaging module uses a double wedge to change the optical path of the reference arm. The reference light incident on the reference arm module is emitted after passing through the reference arm light path lens 1121, is incident on the double wedge prism group, and then is incident on the reference arm mirror 1123. The reference light is reflected by the reference arm mirror 1123 to return into the fiber coupler 1103. The fixed prism 5201 remains stationary, and the movable prism 5203 is driven by the prism driving motor 5205 to move horizontally relative to the fixed prism 5201, thereby changing the optical path length of the reference arm. The movable prism 5203 changes the optical path length of the reference arm by horizontal movement, and cooperates with the light path switching scanning device 1109 to perform scanning, so 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 by using the de-mirroring algorithm, the OCT image using positive and negative frequency image data can be obtained, thereby achieving the purpose of doubling the detection depth.

[0044] Similarly, the double wedge prism group optical path adjusting device can also be assembled in the sample arm, for example, between the fiber collimator 1107 and the light path switching scanning device 1109, and can also serve to adjust the optical path of the sample arm.

[0045] The prism driving motor 5205 can use a voice coil motor or a piezoelectric ceramic mechanical device that can achieve rapid horizontal movement.

[0046] Posterior segment of the eye OCT sample arm module

[0047] The posterior segment of the eye OCT sample arm module includes a light path switching scanning device 1109, an optical path adjusting module 1301, a posterior segment of the eye and fixation beam splitter 1303 (first beam splitter 1303), a refractive adjustment device 1305, a third beam splitter 1307, a pre-beam splitter 1309 (fifth beam splitter 1309), and an objective lens 1311.

[0048] When the posterior segment OCT imaging is performed, the light emitted from the optical fiber collimator 1107 is reflected by the light path switching scanning device 1109. At this time, the light path switching scanning device 1109 is controlled by the computer 1143, and after the light beam is reflected by the light path switching scanning device 1109, the light beam passes through the optical path adjustment module 1301, is reflected by the posterior segment and fixation beam splitter 1303 (the first beam splitter 1303), passes through the refractive adjustment device 1305, is reflected by the third beam splitter 1307, is reflected by the pre-beam splitter 1309 (the fifth beam splitter 1309), and finally reaches the human eye E through the objective lens 1311, and is finally focused on the human eye fundus Er. The detection light beam of the posterior segment OCT imaging light path system satisfies that the central line of the scanning light beam converges near the pupil of the human eye, and the OCT light beam is focused on the human eye fundus Er at any moment.

[0049] The light path switching scanning device 1109 is controlled by the computer 1143 and is in a position for implementing the posterior segment OCT imaging. At this time, the light path switching scanning device 1109 is in a position such that the included angle between the main optical axis of the incident light from the optical fiber collimator 1107 and the main optical axis of the reflected light is α. The fundus OCT imaging light path refractive adjustment device 1305 is adjusted for different human eyes (with different refractive powers) so that the OCT light beam can converge on the human eye fundus Er. That is, the light beam is focused on the retina, which can effectively improve the signal-to-noise ratio and lateral resolution of the OCT image when the retina is measured.

[0050] The light path switching scanning device 1109 not only plays a scanning role but also plays a light path switching role. The galvanometer or other high-precision positioning mechanism adopted in the utility model can meet the requirements of rapid switching and scanning of the system light path. When the fundus is measured, the light path switching scanning device 1109 is rotated so that the main optical axis of the light path is reflected from the optical fiber collimator 1107 to the optical path adjustment module 1301, and the main optical axis of the light beam is changed by an angle α (as shown in the drawing); when the anterior segment is measured, the light path switching scanning device 1109 is rotated so that the main optical axis of the light path is reflected from the optical fiber collimator 1107 to the first reflector 1501, and the main optical axis of the light beam is changed by an angle β (as shown in the drawing). The light path switching scanning device 1109 cooperates with the third beam splitter 1307 to switch the light paths of the anterior and posterior segments.

[0051] The optical path adjustment module 1301 can be composed of a corner cube prism, a right-angle prism, or two mutually perpendicular total reflection mirrors. The optical path adjustment module 1301 can change the optical path by moving up and down as shown in the drawing.

[0052] The light path switching scanning device 1109 can be a one-dimensional light path switching scanning device, or a two-dimensional or three-dimensional light path switching scanning device.

[0053] Anterior segment OCT sample arm module

[0054] The anterior segment OCT sample arm module comprises an optical path switching scanning device 1109, a first mirror 1501, a first lens 1503, a third mirror 1505, a fifth mirror 1507, a third lens 1509, a third beam splitter 1307, a front beam splitter 1309 (fifth beam splitter 1309), and an ocular objective 1311.

[0055] When the anterior segment OCT imaging is performed, the light emitted from the optical fiber collimator 1107 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, and after the light beam is reflected by the optical path switching scanning device 1109, it is successively reflected by the first mirror 1501, transmitted by the first lens 1503, reflected by the third mirror 1505 and the fifth mirror 1507, transmitted by the third lens 1509, transmitted by the third beam splitter 1307, reflected by the front beam splitter 1309 (fifth beam splitter 1309) to the ocular objective 1311, and finally converged to the anterior segment of the human eye through the human eye E. The detection light beam of the anterior segment OCT imaging optical path system satisfies that the OCT light beam is focused on the anterior segment of the human eye.

[0056] The optical path switching scanning device 1109 is controlled by the computer 1143 and is in a position for implementing the anterior segment OCT imaging. At this time, the position of the optical path switching scanning device 1109 is just such that the included angle between the principal axis of the incident light coming from the optical fiber collimator 1107 and the principal axis of the reflected light is β.

[0057] In this embodiment, the detection depth of the OCT system is increased by the double-coupler prism group loading frequency technology, or the Doppler frequency shift technology, in cooperation with the scanning of the optical path switching scanning device 1109, so that the optical path or phase change between adjacent OCT scan A-Scans remains constant, thereby realizing image elimination and deepening the detection depth of the OCT system. The detection depth of the OCT system can realize one-time detection imaging from the cornea to the posterior surface of the lens (the tissue depth from the cornea to the posterior surface of the lens is about 8mm), but it is insufficient to realize single OCT imaging from the cornea to the retina (note: the average eye axial length from the cornea to the retina of the human eye is about 24mm (tissue depth)). If the loading frequency technology is not used, but the scanning frequency domain OCT or the frequency domain spectrometer technology with deeper detection depth is used, although the purpose of increasing the detection depth of the OCT system can also be achieved, the cost of the scanning frequency domain OCT or the frequency domain spectrometer technology with deeper detection depth is often higher. The pixel number of the spectrometer line camera of the frequency domain spectrometer technology with deeper detection depth often needs to be doubled, and the increase in cost often adds more times. The loading frequency technology in the embodiment of the utility model realizes the purpose of doubling the detection depth with only limited cost increase under the condition of ensuring the same imaging resolution and image quality.

[0058] The above is further detailed description of the present application in combination with specific / preferred embodiments, and cannot be deemed as limitation of the specific implementation of the present application to these descriptions. For ordinary skilled in the art to which the present application belongs, without departing from the concept of the present application, they can make several substitutions or variations to the described embodiments, and these substitutions or variations shall be deemed as falling within the protection scope of the present application. In the description of the present application, the description of the reference terms "an embodiment", "some embodiments", "preferred embodiment", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are contained in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner. In the case of not contradicting each other, the skilled in the art can combine and combine the different embodiments or examples described in the present application and the features of different embodiments or examples. Although the embodiments of the present application and its advantages have been described in detail, it should be understood that various changes, substitutions and modifications can be made in the present application without departing from the scope of the patent application.

Claims

1. An ophthalmic measurement system with a dual-wedge prism optical system, comprising an OCT imaging module, the OCT imaging module comprising an OCT light source, a reference arm module, an OCT sample arm module, a fiber coupler and a detector, the OCT sample arm module comprising an optical path switching scanning device, an ocular posterior OCT sample arm optical path and an ocular anterior OCT sample arm optical path, the probe light outputted by the fiber coupler entering the ocular posterior OCT sample arm optical path or the ocular anterior OCT sample arm optical path after being reflected by the optical path switching scanning device at different angles; characterized in that, The application also discloses a double-wedge prism group arranged in the reference arm module or the OCT sample arm module, the double-wedge prism group comprising a fixed prism and a movable prism, the movable prism being parallelly movable relative to the fixed prism so as to change the optical path length of the light path.

2. The ophthalmic measuring system of claim 1, wherein, The movable prism is connected with a prism driving motor, and the movable prism is driven by the prism driving motor.

3. The ophthalmic measuring system of claim 1, wherein, The reference arm module comprises a reference arm light path lens and a reference arm mirror, the double-wedge prism group being arranged between the reference arm light path lens and the reference arm mirror, the reference light being reflected by the reference arm mirror after passing through the reference arm light path lens and the double-wedge prism group and then returning into the fiber coupler.

4. The ophthalmic measuring system of claim 1, wherein, The double-wedge prism group is arranged between a fiber collimator and the light path switching scanning device, and the probe light is incident on the light path switching scanning device after passing through the fiber collimator and the double-wedge prism group.

5. The ophthalmic measuring system of any one of claims 1 to 4, wherein, The driving of the prism is a voice coil motor or a piezoelectric ceramic device.

6. The ophthalmic measuring system of any one of claims 1 to 4, wherein, The anterior segment OCT sample arm light path comprises a first mirror, a first lens, a third mirror, a fifth mirror, a third lens, a third beam splitter, a pre-beam splitter and an objective lens, the light beam being reflected by the light path switching scanning device, then being reflected by the first mirror, being transmitted by the first lens, being reflected by the third mirror and the fifth mirror, being transmitted by the third lens, being transmitted by the third beam splitter, being reflected by the pre-beam splitter and then being reflected by the objective lens, and finally being converged by the human eye to the anterior segment of the human eye.

7. The ophthalmic measuring system of any one of claims 1 to 4, wherein, The posterior segment OCT sample arm light path comprises, in sequence, an optical path length adjusting module, an eye posterior segment and fixation beam splitter, a refractive adjusting device, a third beam splitter, a pre-beam splitter and an objective lens, the light beam being reflected by the light path switching scanning device, then passing through the optical path length adjusting module, being reflected by the eye posterior segment and fixation beam splitter, passing through the refractive adjusting device, being reflected by the third beam splitter, being reflected by the pre-beam splitter and then being reflected by the objective lens, and finally being converged by the human eye to the fundus of the human eye.

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