Anterior segment thickness measuring system
By combining a slant imaging dual telecentric zoom lens and an optical path deflector, the problems of low accuracy and poor comfort in corneal thickness measurement in existing technologies have been solved, achieving high-precision, non-contact anterior segment thickness measurement and expanding the multi-parameter measurement capabilities of ophthalmic equipment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-27
- Publication Date
- 2026-04-07
AI Technical Summary
Existing methods for measuring corneal thickness, such as ultrasonic measurement, suffer from low accuracy, poor comfort, and require professional operation, making it difficult to meet the requirements for high precision.
By employing a slant imaging dual telecentric zoom lens, combined with an illumination device and an optical path deflector, non-contact and non-destructive anterior segment thickness measurement can be achieved. By selecting an appropriate magnification through the zoom mode, a larger measurement depth can be achieved while eliminating imaging distortion and defocusing within the field of view.
It achieves high-precision and comfortable anterior segment thickness measurement, can clearly image and calculate geometric length, is independent of the optical path of optometry instruments, and expands the multi-parameter measurement performance of ophthalmic equipment.
Smart Images
Figure CN224096071U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of ophthalmic imaging, and more particularly to a system for measuring the thickness of the anterior segment of the eye. Background Technology
[0002] Studies have found that corneal thickness is crucial in intraocular pressure (IOP) measurement. When the central corneal thickness deviates significantly from the normal value, the IOP reading is affected. Current methods for measuring corneal thickness primarily include ultrasound. However, ultrasound requires anesthesia, involves the probe contacting the patient's cornea, and aligning the sound beam with the patient's visual axis is challenging, resulting in relatively low measurement accuracy (approximately 0.1–0.12 mm). Furthermore, ultrasound generally requires highly trained professionals to operate. As shown above, even a 10 μm change in corneal thickness can lead to a significant change in IOP. Therefore, ultrasound measurement, being a contact method, is difficult, uncomfortable, and cannot meet the high precision requirements of traditional methods. Utility Model Content
[0003] This application aims to provide a high-precision anterior segment thickness measurement system.
[0004] To achieve the above objectives, the technical solution of this application is as follows:
[0005] An oblique imaging dual telecentric zoom lens, wherein one side of the oblique imaging dual telecentric zoom lens is a receiving surface and the other side is a receiving surface; the oblique imaging dual telecentric zoom lens includes: a front fixation group, a zoom group, a compensation group, and a rear fixation group arranged sequentially along the direction from the receiving surface to the receiving surface; wherein...
[0006] The front fixing group includes: a first lens and a second lens arranged sequentially along the direction from the side surface to the receiving surface;
[0007] The zoom group includes a third lens and a fourth lens arranged sequentially along the direction from the side surface to the receiving surface;
[0008] The compensation group includes a fifth lens, a sixth lens, and a seventh lens arranged sequentially along the side surface to the receiving surface;
[0009] The rear fixing group includes an eighth lens, a ninth lens, a tenth lens, an eleventh lens, a twelfth lens, and a thirteenth lens arranged sequentially from the side to the receiving surface.
[0010] Optionally, the first lens is a positive meniscus lens, the second lens is a positive meniscus lens, and the first lens and the second lens are cemented together to form a cemented doublet lens.
[0011] Optionally, the third lens is a negative meniscus lens, the fourth lens is a positive meniscus lens, and the third lens and the fourth lens are cemented together to form a cemented doublet lens.
[0012] Optionally, the fifth lens is a biconvex lens, the sixth lens is a negative meniscus lens, the seventh lens is a positive meniscus lens, and the sixth lens and the seventh lens are cemented together to form a cemented doublet lens.
[0013] Optionally, the eighth lens is a positive meniscus lens, the ninth lens is a positive meniscus lens, the tenth lens is a biconvex lens, the eleventh lens is a biconcave lens, the twelfth lens is a positive meniscus lens, and the thirteenth lens is a negative meniscus lens; the eighth lens and the ninth lens are cemented together to form a cemented doublet lens, the tenth lens and the eleventh lens are cemented together to form a cemented doublet lens, and the twelfth lens and the thirteenth lens are cemented together to form a cemented doublet lens.
[0014] Optionally, the oblique imaging dual telecentric zoom lens further includes an aperture stop, which is located between the compensation group and the rear fixation group.
[0015] Optionally, both the side surface and the receiving surface are inclined to the oblique imaging dual telecentric zoom lens.
[0016] An anterior segment thickness measurement system, comprising,
[0017] A lighting device that emits light;
[0018] A light path deflector is located in the light path of the light emitted by the illumination device, and reflects the light emitted by the illumination device to the eye of the person being tested.
[0019] As provided in any of the above, the oblique imaging dual telecentric zoom lens is located in the reflected light path of the light reflected from the eye under test.
[0020] Optionally, the anterior segment thickness measurement system further includes: an imaging receiver located on the side of the oblique imaging dual telecentric zoom lens away from the human eye being measured; and the light emitted by the illumination device includes slit light.
[0021] Optionally, the human eye under test, the oblique imaging dual telecentric zoom lens, and the imaging receiver are distributed according to Schahm's law.
[0022] The oblique imaging dual telecentric zoom lens of this application employs a zoom mechanism, allowing for the selection of appropriate magnification based on different human eyes. It can accommodate larger measurement depths and resolves the image distortion and partial defocusing issues within the field of view caused by the near-to-far imaging principle and depth-of-field limitations of ordinary lenses. When applied to anterior segment thickness measurement systems, this oblique imaging dual telecentric zoom lens enables non-contact, non-destructive measurement with high comfort and high-precision accuracy.
[0023] The anterior segment thickness measurement system of this application can obtain an image of the posterior surface of the lens, with clear imaging within a certain depth, eliminating parallax and facilitating the calculation of geometric length. The anterior segment thickness measurement is not perpendicular to the lens optical axis, and clear imaging is maintained within a designed tilt angle range, facilitating image processing for lens and corneal thickness calculations. Furthermore, as an independent device, this anterior segment thickness measurement system can be installed independently within an existing optometry instrument without sharing the optical path, provided it does not interfere with other instruments. This expands the multi-parameter measurement capabilities of ophthalmic equipment, allows for correction of related parameters, and ensures the accuracy of measurement data.
[0024] To make the above features and advantages of this application more apparent and understandable, specific embodiments are described below in conjunction with the accompanying drawings. Attached Figure Description
[0025] Figure 1 This is a schematic diagram of a slant imaging dual telecentric zoom lens proposed in this application.
[0026] Figure 2 This is a schematic diagram of the dual telecentric zoom lenses for oblique imaging at different magnifications proposed in this application.
[0027] Figure 3 This is a schematic diagram of the dual telecentric zoom lens imaging at different magnifications proposed in this application.
[0028] Figure 4 The MTF chart is for a 0.4x oblique imaging dual telecentric zoom lens.
[0029] Figure 5 The distortion curve is shown for a 0.4x oblique imaging dual telecentric zoom lens.
[0030] Figure 6 Light field diagrams for oblique imaging dual telecentric zoom lenses with 0.4 magnification at different image planes.
[0031] Figure 7 The MTF chart is for a 0.5x oblique imaging dual telecentric zoom lens.
[0032] Figure 8 The distortion curve is shown for a 0.5x oblique imaging dual telecentric zoom lens.
[0033] Figure 9 Light field diagrams for oblique imaging dual telecentric zoom lenses with 0.5x magnification at different image planes.
[0034] Figure 10 The MTF chart is for a 0.6x oblique imaging dual telecentric zoom lens.
[0035] Figure 11 The distortion curve is shown for a 0.6x oblique imaging dual telecentric zoom lens.
[0036] Figure 12 Light field diagrams for oblique imaging dual telecentric zoom lenses with 0.6 magnification at different image planes.
[0037] Figure 13 A structural diagram of an anterior segment thickness measurement system provided in this application.
[0038] In the accompanying drawings, similar reference numerals refer to the same elements. Detailed Implementation
[0039] To make the objectives and technical solutions of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the described embodiments of this application without creative effort are within the scope of protection of this application.
[0040] In one embodiment of this application, please refer to Figure 1 ,like Figure 1 The diagram shown is a schematic of an oblique imaging dual telecentric zoom lens proposed in this application. One side of the oblique imaging dual telecentric zoom lens (e.g.) Figure 1 The left side of the image is 5, and the other side (such as...) Figure 1 The right side of the image (in the image) is the receiving surface 6; the oblique imaging dual telecentric zoom lens includes: along the direction from the receiving side 5 to the receiving surface 6 (e.g., the right side of the image) is the receiving surface 6; Figure 1 The four groups (front fixed group 1, zoom group 2, compensation group 3, and rear fixed group 4) are arranged sequentially from left to right.
[0041] The front fixing group 1 includes a first lens 11 and a second lens 12 arranged sequentially along the direction from the side surface 5 to the receiving surface 6;
[0042] The zoom group 2 includes a third lens 21 and a fourth lens 22 arranged sequentially along the direction from the receiving side 5 to the receiving side 6;
[0043] Compensation group 3 includes: a fifth lens 31, a sixth lens 32 and a seventh lens 33 arranged sequentially along the direction from the side surface 5 to the receiving surface 6;
[0044] The rear fixing group 4 includes an eighth lens 41, a ninth lens 42, a tenth lens 43, an eleventh lens 44, a twelfth lens 45, and a thirteenth lens 46 arranged sequentially along the direction from the receiving side 5 to the receiving side 6.
[0045] The oblique imaging dual telecentric zoom lens of this application employs a zoom mechanism, allowing for the selection of appropriate magnification based on different human eyes. It can accommodate larger measurement depths and resolves the image distortion and partial defocusing issues within the field of view caused by the near-to-far imaging principle and depth-of-field limitations of ordinary lenses. When applied to anterior segment thickness measurement systems, this oblique imaging dual telecentric zoom lens enables non-contact, non-destructive measurement with high comfort and high-precision accuracy.
[0046] Specifically, the first lens 11 can be a positive meniscus lens, the second lens 12 can be a positive meniscus lens, and the first lens 11 and the second lens 12 can be cemented together to form a cemented doublet lens.
[0047] As an example, the third lens 21 can be a negative meniscus lens, the fourth lens 22 can be a positive meniscus lens, and the third lens 21 and the fourth lens 22 can be cemented together to form a cemented doublet lens.
[0048] As an example, the fifth lens 31 can be a biconvex lens, the sixth lens 32 can be a negative meniscus lens, and the seventh lens 33 can be a positive meniscus lens. The sixth lens 32 and the seventh lens 33 can be cemented together to form a cemented doublet lens.
[0049] As an example, the eighth lens 41 can be a positive meniscus lens, the ninth lens 42 can be a positive meniscus lens, the tenth lens 43 can be a biconvex lens, the eleventh lens 44 can be a biconcave lens, the twelfth lens 45 can be a positive meniscus lens, and the thirteenth lens 46 can be a negative meniscus lens. The eighth lens 41 and the ninth lens 42 can be cemented together to form a cemented doublet lens, the tenth lens 43 and the eleventh lens 44 can be cemented together to form a cemented doublet lens, and the twelfth lens 45 and the thirteenth lens 46 can be cemented together to form a cemented doublet lens. Cementing the lenses together to form a cemented doublet lens can effectively correct spherical aberration.
[0050] As an example, a slant-image dual telecentric zoom lens may also include an aperture stop 7, which may be located between the compensation group 3 and the rear fixed group 4. Specifically, the distances between the aperture stop 7 and the compensation group 3, as well as the distances between the aperture stop 7 and the fixed group 4, can be set according to actual needs, and are not specifically limited here.
[0051] As an example, the side surface 5 and the receiving surface 6 can both be tilted to the oblique imaging dual telecentric zoom lens; specifically, the side surface 5 is tilted to the surface of the first lens 11, and the receiving surface 6 is tilted to the surface of the thirteenth lens 46; more specifically, the plane where the side surface 5 is located can be obliquely intersecting the plane where the receiving surface 6 is located.
[0052] As an example, each of the lenses in the first lens 11 to the thirteenth lens 46 may adopt a spherical design; specifically, each lens may, but is not limited to, use mass-produced glass from Chengdu Guangming.
[0053] As an example, please refer to Table 1, which provides the structural data of the oblique imaging dual telecentric zoom lens provided in this embodiment. In the table, R is the radius of curvature of each lens surface, D is the distance from the corresponding optical surface to the next optical surface on the optical axis, ne is the refractive index of the corresponding lens, Vd is the Abbe number, zoom1 is the spacing parameter between the rear surface of the second lens 12 and the front surface of the third lens 21, zoom2 is the spacing parameter between the rear surface of the fourth lens 22 and the front surface of the fifth lens 31, and zoom3 is the spacing parameter between the rear surface of the seventh lens 33 and the aperture stop 7. Specifically, the units of the radius of curvature R of the lens surface and the distance D from the corresponding optical surface to the next optical surface on the optical axis are both mm.
[0054] Table 1. Structural Data of Oblique Imaging Dual Telecentric Zoom Lens
[0055]
[0056] For example, please refer to Figure 2 and Figure 3 ,like Figure 2 The diagram shown is a schematic of the dual telecentric zoom lens with different magnifications for oblique imaging proposed in this application. Figure 2 Figure (a) shows a schematic diagram of a 0.4x oblique imaging dual telecentric zoom lens. Figure 2 Figure (b) shows a schematic diagram of a 0.5x oblique imaging dual telecentric zoom lens. Figure 2 Figure (c) in the diagram is a schematic diagram of a 0.6x oblique imaging dual telecentric zoom lens; as shown in Figure (c). Figure 3 The image shown is a schematic diagram of the dual telecentric zoom lens imaging at different magnifications proposed in this application. Figure 3 Figure (a) shows a schematic diagram of oblique imaging with a dual telecentric zoom lens at 0.4 magnification. Figure 3 Figure (b) shows a schematic diagram of oblique imaging with a dual telecentric zoom lens at 0.5x magnification. Figure 3 Figure (c) shows a schematic diagram of oblique imaging with a dual telecentric zoom lens at 0.6 magnification.
[0057] As an example, please refer to Table 2, which shows the spacing parameters of the oblique imaging dual telecentric zoom lens provided in this embodiment. When a magnification of 0.6 is required, the spacing parameter zoom1 between the rear surface of the second lens 12 and the front surface of the third lens 21 is 19.7 mm, the spacing parameter zoom2 between the rear surface of the fourth lens 22 and the front surface of the fifth lens 31 is 55.3 mm, and the spacing parameter zoom3 between the rear surface of the seventh lens 33 and the aperture stop 7 is 40.3 mm. When a magnification of 0.5 is required, the spacing parameter zoom1 between the rear surface of the second lens 12 and the front surface of the third lens 21 is 17.0 mm, the spacing parameter zoom2 between the rear surface of the fourth lens 22 and the front surface of the fifth lens 31 is 75.2 mm, and the spacing parameter zoom3 between the rear surface of the seventh lens 33 and the aperture stop 7 is 23.0 mm. When a magnification of 0.4 is required, the zoom parameter (zoom1) between the rear surface of the second lens 12 and the front surface of the third lens 21 is 0.1 mm, the zoom parameter (zoom2) between the rear surface of the fourth lens 22 and the front surface of the fifth lens 31 is 110.4 mm, and the zoom parameter (zoom3) between the rear surface of the seventh lens 33 and the aperture 7 is 4.7 mm.
[0058] Table 2. Parameters of the Interval Between Oblique Imaging Dual Telecentric Zoom Lenses
[0059] magnification 0.6 0.5 0.4 Zoom1 19.7 17.0 0.1 Zoom2 55.3 75.2 110.4 Zoom3 40.3 23.0 4.7
[0060] For example, please refer to Figure 4 ,like Figure 4 The image shows the MTF (Mean Transformer Frequency) plot of a 0.4x oblique imaging dual telecentric zoom lens. The horizontal axis represents spatial frequency in millimeters (mm), and the vertical axis represents the OTF modulus. A higher OTF modulus (closer to 1) indicates a stronger ability of the optical system to transmit details at that spatial frequency, resulting in better image quality. Figure 4 It can be seen that the OTF modulus limit is close to 1 at low frequencies, while the OTF modulus is greater than 0.6 at high frequencies. Please continue reading. Figure 5 ,like Figure 5 The image shows the distortion curve of a 0.4x oblique imaging dual telecentric zoom lens. Figure 5 It can be seen that the distortion of this oblique imaging dual telecentric zoom lens is less than 0.06% at 0.4x magnification. Please continue reading. Figure 6 ,like Figure 6 The image shows the ray fan diagrams of a 0.4x oblique imaging dual telecentric zoom lens at different image planes. Figure 6 Figure (a) shows the ray fan diagram of a 3.0000mm, 0.4x oblique imaging double telecentric zoom lens. Figure 6 Figure (b) shows the ray fan diagram of a 2.1000mm, 0.4x oblique imaging dual telecentric zoom lens. Figure 6Figure (c) shows the ray fan diagram of a 0.4x oblique imaging double telecentric zoom lens at an image plane of 0.0000mm. Figure 6 Figure (d) shows the ray fan diagram of a 0.4x oblique imaging double telecentric zoom lens at an image plane of -2.1000mm. Figure 6 Figure (e) shows the ray fan diagram of a 0.4x oblique imaging dual telecentric zoom lens at -3.0000mm magnification on the image plane; different aberrations of the rays can converge to a point on the image plane. This oblique imaging dual telecentric zoom lens has high image quality at 0.4x magnification.
[0061] For example, please refer to Figure 7 ,like Figure 7 The image shown is the MTF plot of a 0.5x oblique imaging dual telecentric zoom lens. Figure 7 As can be seen, the OTF modulus limit is close to 1 at low frequencies, while the OTF modulus is greater than 0.4 at high frequencies. (Continue reading...) Figure 8 ,like Figure 8 The image shows the distortion curve of a 0.5x oblique imaging dual telecentric zoom lens. Figure 8 It can be seen that the distortion of this oblique imaging dual telecentric zoom lens is less than 0.03% at 0.5x magnification. Please continue reading. Figure 9 ,like Figure 9 The image shows the ray fan diagrams of a 0.5x oblique imaging dual telecentric zoom lens at different image planes. Figure 9 Figure (a) shows the ray fan diagram of a 3.0000mm, 0.5x oblique imaging double telecentric zoom lens. Figure 9 Figure (b) shows the ray fan diagram of a 2.1000mm, 0.5x oblique imaging double telecentric zoom lens. Figure 9 Figure (c) shows the ray fan diagram of a 0.5x oblique imaging double telecentric zoom lens at an image plane of 0.0000mm. Figure 9 Figure (d) shows the ray fan diagram of a 0.5x oblique imaging double telecentric zoom lens at an image plane of -2.1000mm. Figure 9 Figure (e) shows the ray fan diagram of a 0.5x oblique imaging dual telecentric zoom lens at -3.0000mm magnification on the image plane; different aberrations of the rays can converge to a point on the image plane. This oblique imaging dual telecentric zoom lens has high image quality at 0.5x magnification.
[0062] For example, please refer to Figure 10 ,like Figure 10 The image shown is the MTF chart of a 0.6x oblique imaging dual telecentric zoom lens. Figure 10 As can be seen, the OTF modulus limit is close to 1 at low frequencies, while the OTF modulus is greater than 0.6 at high frequencies. (Continue reading...) Figure 11 ,like Figure 11The image shows the distortion curve of a 0.6x oblique imaging dual telecentric zoom lens. Figure 11 It can be seen that the distortion of this oblique imaging dual telecentric zoom lens is less than 0.012% at 0.6x magnification. Please continue reading. Figure 12 ,like Figure 12 The image shows the ray fan diagrams of a 0.6x oblique imaging dual telecentric zoom lens at different image planes. Figure 12 Figure (a) shows the ray fan diagram of a 3.0000mm, 0.6x oblique imaging dual telecentric zoom lens. Figure 12 Figure (b) shows the ray fan diagram of a 2.1000mm, 0.6x oblique imaging dual telecentric zoom lens. Figure 12 Figure (c) shows the ray fan diagram of a 0.6x oblique imaging double telecentric zoom lens at an image plane of 0.0000mm. Figure 12 Figure (d) shows the ray fan diagram of a 0.6x oblique imaging double telecentric zoom lens at an image plane of -2.1000mm. Figure 12 Figure (e) shows the ray fan diagram of a 0.6x oblique imaging dual telecentric zoom lens at -3.0000mm magnification on the image plane; different aberrations of the rays can converge to a point on the image plane. This oblique imaging dual telecentric zoom lens has high image quality at 0.6x magnification.
[0063] Further, please refer to Table 3, which provides a comparison of the maximum distortion between the oblique imaging dual telecentric zoom lens and the non-oblique imaging dual telecentric zoom lens provided in this embodiment. As can be seen from Table 3, the imaging distortion does not change much under different magnifications.
[0064] Table 3. Comparison of maximum distortion between oblique imaging dual telecentric zoom lenses and non-oblique imaging dual telecentric zoom lenses.
[0065] Magnification and Imaging Method 0.4 0.5 0.6 Imaging tilt 0.0064% 0.0234% 0.0419% Imaging without tilting 0.0106% 0.0279% 0.0372%
[0066] In another embodiment of this application, please refer to Figures 1 to 12 See Figure 13 This application also provides an anterior segment thickness measurement system 600, which may include,
[0067] Lighting device 300, lighting device 300 emits light;
[0068] The light path deflector 500 is located in the light path of the light emitted by the illumination device 300 and reflects the light emitted by the illumination device 300 to the human eye 200 to be tested.
[0069] The above are as follows Figures 1 to 12 The oblique imaging dual telecentric zoom lens 100 provided in the corresponding embodiment is located on the reflected light path of the light reflected by the human eye 200 under test.
[0070] As an example, the mirror surface of the light path deflector 500 is tilted at an angle to the side of the illumination device 300 that emits light.
[0071] As an example, the human eye under test 200 includes the anterior segment tissue, which is located on the optical path of the light reflected by the optical path deflector 500.
[0072] As an example, the anterior segment thickness measurement system 600 may also include an imaging receiver 400 located on the side of the oblique imaging dual telecentric zoom lens 100 away from the human eye 200 being measured.
[0073] As an example, the light emitted by the lighting device 300 may include slit light.
[0074] As an example, the human eye under test 200, the oblique imaging dual telecentric zoom lens 100, and the imaging receiver 400 are distributed according to Schahm's law.
[0075] The oblique imaging dual telecentric zoom lens used in this application employs a zoom mechanism, allowing for the selection of appropriate magnification based on individual eye preferences. It achieves a greater measurement depth, resolving image distortion and partial defocusing within the field of view caused by the near-to-far imaging principle and depth-of-field limitations inherent in ordinary lenses. It provides a clear image of the posterior surface of the lens within the anterior segment tissue, eliminating parallax and facilitating geometric length calculations. Furthermore, based on Scherm's law, the anterior segment thickness measurement is not perpendicular to the lens optical axis, ensuring clear imaging within the designed tilt angle range, facilitating image processing for lens and corneal thickness calculations. Simultaneously, the anterior segment thickness measurement system used in this application is an independent device, not sharing the optical path with existing optometry instruments. Under non-interference conditions, it can be independently installed within the instrument, expanding the ophthalmic equipment's multi-parameter measurement capabilities, enabling related parameter corrections, and ensuring the accuracy of measurement data.
[0076] Although this application has been disclosed above with reference to embodiments, it is not intended to limit this application. Anyone skilled in the art may make some modifications and refinements without departing from the spirit and scope of this application. Therefore, the scope of protection of this application shall be determined by the appended claims.
Claims
1. A system for measuring the thickness of anterior segment, characterized in that, include, A lighting device that emits light; A light path deflector is located in the light path of the light emitted by the illumination device, and reflects the light emitted by the illumination device to the eye of the person being tested. as well as An oblique imaging dual telecentric zoom lens is provided, wherein the lens is located on the reflected light path of the light reflected from the eye of the subject. One side of the lens is the receiving side, and the other side is the receiving side. Both the receiving side and the receiving side are inclined to the lens. The oblique imaging dual telecentric zoom lens includes: a front fixing group, a zoom group, a compensation group, and a rear fixing group arranged sequentially along the direction from the receiving side to the receiving side. The front fixing group includes: a first lens and a second lens arranged sequentially along the direction from the side surface to the receiving surface; The zoom group includes a third lens and a fourth lens arranged sequentially along the direction from the side surface to the receiving surface; The compensation group includes a fifth lens, a sixth lens, and a seventh lens arranged sequentially along the side surface to the receiving surface; The rear fixing group includes an eighth lens, a ninth lens, a tenth lens, an eleventh lens, a twelfth lens, and a thirteenth lens arranged sequentially from the side to the receiving surface.
2. The anterior segment thickness measurement system as described in claim 1, characterized in that, The first lens is a positive meniscus lens, the second lens is a positive meniscus lens, and the first lens and the second lens are cemented together to form a cemented doublet lens.
3. The anterior segment thickness measurement system as described in claim 1, characterized in that, The third lens is a negative meniscus lens, the fourth lens is a positive meniscus lens, and the third lens and the fourth lens are cemented together to form a cemented doublet lens.
4. The anterior segment thickness measurement system as described in claim 1, characterized in that, The fifth lens is a biconvex lens, the sixth lens is a negative meniscus lens, and the seventh lens is a positive meniscus lens. The sixth lens and the seventh lens are cemented together to form a cemented doublet lens.
5. The anterior segment thickness measurement system as described in claim 1, characterized in that, The eighth lens is a positive meniscus lens, the ninth lens is a positive meniscus lens, the tenth lens is a biconvex lens, the eleventh lens is a biconcave lens, the twelfth lens is a positive meniscus lens, and the thirteenth lens is a negative meniscus lens; the eighth lens and the ninth lens are cemented together to form a cemented doublet lens, the tenth lens and the eleventh lens are cemented together to form a cemented doublet lens, and the twelfth lens and the thirteenth lens are cemented together to form a cemented doublet lens.
6. The anterior segment thickness measurement system as described in claim 1, characterized in that, The oblique imaging dual telecentric zoom lens also includes an aperture stop, which is located between the compensation group and the rear fixation group.
7. The anterior segment thickness measurement system as described in any one of claims 1 to 6, characterized in that, The anterior segment thickness measurement system further includes: an imaging receiver located on the side of the oblique imaging dual telecentric zoom lens away from the human eye being measured; and the light emitted by the illumination device includes slit light.
8. The anterior segment thickness measurement system as described in claim 7, characterized in that, The human eye under test, the oblique imaging dual telecentric zoom lens, and the imaging receiver are distributed according to Schahm's law.