Eye parameter measuring instrument

Abstract

This invention provides an eye parameter measuring instrument, including a wavefront pre-compensation device, a wavefront aberration measuring device, and a corneal topography measuring device. The wavefront pre-compensation device includes a compensation light source, a collimating lens, and a first 4f system. The wavefront aberration measuring device includes a second 4f system, a first beam splitter, and a wavefront aberrometer. The corneal topography measuring device includes a Placido disc structure, a third 4f system, a second beam splitter, and an image acquisition element. The Placido disc structure faces the subject's eye. The optical paths of the first and third 4f systems intersect at the second beam splitter; the optical paths of the second and third 4f systems intersect at the first beam splitter. By incorporating the wavefront aberration measuring device and the corneal topography measuring device, this invention can simultaneously measure the wavefront aberration and corneal topography of the eye in a single examination, reducing the number of examinations required for the subject and avoiding random errors caused by multiple examinations.

Description

[Technical Field]

[0001] This invention belongs to the field of ophthalmic medical device technology, and more specifically, relates to an eye parameter measuring instrument. [Previous Technology]

[0002] The cornea is the transparent, anterior part of the eye, located at the anterior 1 / 6 of the eyeball wall. It is an avascular, transparent fibrous membrane. It covers the iris, pupil, and anterior chamber, providing most of the eye's refractive power and playing a vital role in maintaining the integrity of the eyeball, protecting it, and maintaining vision. The corneal radius of curvature is an important parameter of the cornea. Within the circular area near the pupillary region of the central cornea, due to its near-spherical shape, the radius of curvature at each point is approximately equal. However, in the intermediate and peripheral corneal regions outside the central area, the cornea is flatter, and the radius of curvature at each point is not equal.

[0003] Corneal topography is a commonly used method to describe the local topography of the corneal surface. It can reflect the shape of various points on the corneal surface. From the corneal topography, the curvature radius of each point on the examiner's cornea can be determined, and the overall changes on the corneal surface can also be assessed. A corneal topography instrument is a device used to detect corneal topography. At present, the most widely used instrument is the Placido corneal topography instrument.

[0004] The Placido disc consists of a set of concentric rings (usually 16, 32, or 36). The disc is placed in front of the subject's eyeball, and its projection onto the corneal surface is captured by a CCD. This allows for the calculation of corneal morphology information and the determination of corneal lesions. If the corneal surface is normal, the spacing between the rings is a regular concentric ring pattern. If the corneal surface morphology is abnormal, the distance between the rings in the reflected image is irregular. For the collected ring images, the smaller the spacing between the concentric rings, the steeper the cornea; the larger the spacing, the flatter the cornea.

[0005] In visual optics, defocus and astigmatism, two optical defects that can be corrected by spherical lenses, are called low-order aberrations. However, besides defocus and astigmatism, the eye also has other higher-order aberrations. These higher-order aberrations cannot be corrected by wearing lenses and will affect the image quality of the eye to some extent. Eye aberrations are mainly affected by two factors: the cornea and the lens. Corneal aberrations can be calculated using Placido corneal topography, but intraocular aberrations cannot be analyzed from corneal topography. The SH (Shack-Hartmann) wavefront aberrometer is currently a commonly used principle for detecting ocular wavefront aberrations. It features simple structure, fast measurement speed, and strong vibration resistance. It can record wavefront changes in real time and has wide applications in self-adjusting optics, ocular aberration detection, optical element surface shape detection, and optical system wavefront aberration detection.

[0006] However, the SH wavefront aberrometer can only measure the wavefront aberration of active light sources. Therefore, during the measurement, a collimated laser light source is used to illuminate the eye. The collimated laser incident on the eye forms a light spot on the retina. After receiving the reflected light from the retina, this light spot propagates in all directions as a point light source. Most of the light is absorbed by the inner wall of the eyeball, and a small portion of the light carries wavefront information and is emitted. The eye aberration can be measured based on the reflected image.

[0007] The overall aberration data of the eye can be obtained by measuring and calculating the Placido corneal topography and the measurement results of the SH wavefront aberrometer. However, random errors will inevitably occur when the two instruments are measured multiple times, and long-term measurement will also affect the final aberration data of the eye. [Summary of the Invention]

[0008] The purpose of this invention is to provide an eye parameter measuring instrument to solve the technical problem in the prior art that eye parameters need to be measured multiple times by multiple instruments, resulting in random errors.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows: An eye parameter measuring instrument is provided, comprising a wavefront pre-compensation device, a wavefront aberration measuring device, and a corneal topography measuring device; the wavefront pre-compensation device comprises a compensation light source, a collimating lens, and a first 4f system arranged sequentially; the wavefront aberration measuring device comprises a second 4f system, a first beam splitter, and a wavefront aberrometer arranged sequentially; the corneal topography measuring device comprises a Placido disc structure, a third 4f system, a second beam splitter, and an image acquisition element arranged sequentially; the Placido disc structure faces the eye of the subject; wherein the optical paths of the first 4f system and the third 4f system intersect at the second beam splitter; the optical paths of the second 4f system and the third 4f system intersect at the first beam splitter.

[0010] Further, the compensation light source includes a first light source, a second light source and a coupling optical fiber, wherein the light beam emitted by the first light source and the light beam emitted by the second light source are combined into a single light beam through the coupling optical fiber; the first light source is used to provide a light source for the wavefront aberration measurement device; and the second light source is used to determine whether the eye position of the subject is correct.

[0011] Further, the first 4f system includes a first front achromatic lens and a first rear achromatic lens arranged sequentially.

[0012] Further, the second beam splitter is disposed between the first front achromatic lens and the first rear achromatic lens.

[0013] Further, the second 4f system includes a second front achromatic lens and a first rear achromatic lens, and the first beam splitter and the second beam splitter are sequentially disposed between the second front achromatic lens and the first rear achromatic lens.

[0014] Further, the eye parameter measuring instrument also includes a first aperture stop, which is disposed between the first beam splitter and the second beam splitter, or the first aperture stop is disposed between the second front achromatic lens and the first beam splitter.

[0015] As another preferred embodiment, the second beam splitter is disposed between the first rear achromatic lens and the Placido disc structure.

[0016] As another preferred embodiment, the second 4f system includes a second front achromatic lens and a second rear achromatic lens, the second beam splitter is disposed between the second rear achromatic lens and the Placido disc structure; the first beam splitter is disposed between the second front achromatic lens and the second rear achromatic lens.

[0017] As another preferred embodiment, the eye parameter measuring instrument further includes a first aperture stop, which is disposed between the second front achromatic lens and the first beam splitter; or, the first aperture stop is disposed between the first beam splitter and the second rear achromatic lens.

[0018] Further, the third 4f system includes a third front achromatic lens and a first rear achromatic lens, and the first beam splitter and the second beam splitter are sequentially disposed between the third front achromatic lens and the first rear achromatic lens.

[0019] As another preferred embodiment, the third 4f system includes a third front achromatic lens and a second rear achromatic lens, the second beam splitter is disposed between the second rear achromatic lens and the Placido disc structure; the first beam splitter is disposed between the third front achromatic lens and the second rear achromatic lens.

[0020] Furthermore, the eye parameter measuring instrument also includes a second aperture, which is disposed between the third front achromatic lens and the first beam splitter.

[0021] Furthermore, the eye parameter measuring instrument also includes a first bandpass filter, which is disposed between the wavefront aberrometer and the third front achromatic lens.

[0022] Furthermore, the eye parameter measuring instrument also includes a second bandpass filter, which is disposed between the image acquisition element and the second front achromatic lens.

[0023] Furthermore, the Placido disc structure is provided with an illumination unit.

[0024] The beneficial effects of the eye parameter measuring instrument provided by the present invention are as follows:

[0025] (1) Compared with the prior art, in this invention, by setting up a wavefront pre-compensation device, a wavefront aberration measurement device and a corneal topography measurement device, the wavefront aberration and corneal topography of the eye can be measured simultaneously in one examination, reducing the number of examinations for the examinee and avoiding random errors caused by multiple examinations.

[0026] (2)Compared with the prior art, the present invention integrates wavefront aberration and corneal topography measurements, and can obtain comprehensive data in one examination, reducing the number of examinations, which not only improves examination efficiency, but also reduces patients' waiting time and discomfort, and enhances the overall medical experience.

[0027] (3)Compared with the prior art, in this invention, by introducing the first 4f system, the second 4f system and the third 4f system, not only is optical distortion effectively reduced and the stability and reliability of the system improved, but also the complex optical components are reduced, the overall structure is simplified, thereby reducing the overall manufacturing cost and improving production efficiency.

[0028] (4) Compared with the prior art, in this invention, by introducing a third 4f system into the corneal topography measurement device, the magnification consistency of the Placido disc structure is ensured, making the measurement results of the corneal topography map more accurate. In addition, the measurement results of wavefront aberration can be used as a supplement to the corneal topography, further improving the accuracy of the measurement.

[0029] (5)Compared with the prior art, the eye parameter measuring instrument of the present invention has strong adaptability. The lens combination in the first 4f system, the second 4f system and the third 4f system, as well as the number of rings of the Placido disc structure, can be adjusted according to the specific situation of the examinee to adapt to examinees with different corneal sizes, thereby improving the applicability and flexibility of the instrument.

Implementation Method

[0030] To make the technical problems, technical solutions, and beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0031] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to or indirectly connected to the other element.

[0032] It should be understood that the terms “length”, “width”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inner”, “outer”, etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the 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.

[0033] 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 this invention, "more" means two or more, unless otherwise expressly and specifically defined.

[0034] Please refer to Figures 1 to 4 together. The eye parameter measuring instrument provided in the embodiments of the present invention will now be described. The eye parameter measuring instrument includes a wavefront precompensation device, a wavefront aberration measuring device, and a corneal topography measuring device. The wavefront precompensation device includes a compensation light source, a collimating lens 104, and a first 4f system arranged in sequence. The wavefront aberration measuring device includes a second 4f system, a first beam splitter 203, and a wavefront aberrometer 304 arranged in sequence. The corneal topography measuring device includes a Placido disc structure 401, a third 4f system, a second beam splitter 201, and an image acquisition element 207 arranged in sequence. The Placido disc structure 401 faces the subject's eye. The optical paths of the first 4f system and the third 4f system intersect at the second beam splitter 201. The optical paths of the second 4f system and the third 4f system intersect at the first beam splitter 203.

[0035] Compared with the prior art, the eye parameter measuring instrument provided by the present invention, by setting a wavefront pre-compensation device, a wavefront aberration measuring device and a corneal topography measuring device, can simultaneously measure the wavefront aberration and corneal topography of the eye in one examination, reducing the number of examinations for the examinee and avoiding the random errors caused by multiple examinations.

[0036] In this embodiment of the invention, wavefront aberration and corneal topography measurements are integrated together, and comprehensive data can be obtained in one examination, reducing the number of examinations, improving examination efficiency, reducing patient waiting time and discomfort, and enhancing the overall medical experience.

[0037] In this embodiment of the invention, by introducing the first 4f system, the second 4f system and the third 4f system, not only is optical distortion effectively reduced and the stability and reliability of the system improved, but also complex optical components are reduced, the overall structure is simplified, thereby reducing the overall manufacturing cost and improving production efficiency.

[0038] In this embodiment of the invention, by introducing a third 4f system into the corneal topography measurement device, the magnification consistency of the Placido disc structure 401 is ensured, making the measurement results of the corneal topography map more accurate. Furthermore, the wavefront aberration measurement results can serve as a supplement to the corneal topography measurement, further improving the accuracy of the measurement.

[0039] The eye parameter measuring instrument of the present invention has strong adaptability. The lens combination in the first 4f system, the second 4f system and the third 4f system, as well as the number of rings of the Placido disc structure 401, can be adjusted according to the specific situation of the examinee to adapt to examinees with different corneal sizes, thereby improving the applicability and flexibility of the instrument.

[0040] It can be understood that a 4f system utilizes the characteristics of two lenses and optical Fourier transform to achieve spatial frequency modulation and analysis. The name 4f system comes from its structure. If the focal length f1 of lens L1 is equal to the focal length f2 of lens L2, the total system distance is 4f, which is a standard 4f system, and the light field regions of the image plane and the object plane are in a 1:1 ratio. If the focal lengths of L1 and L2 are different, then, except for the scaling ratio of the light field size (horizontal and vertical directions of the image plane) compared to the standard 4f system being f2:f1, the other functions are the same as the standard 4f system.

[0041] In one embodiment of the present invention, please refer to Figures 1 to 4 together. The compensation light source includes a first light source 101, a second light source 102 and a coupling optical fiber 103. The light beam emitted by the first light source 101 and the light beam emitted by the second light source 102 are combined into a single light beam through the coupling optical fiber 103. The first light source 101 is used to provide a light source for the wavefront aberration measurement device. The second light source 102 is used to determine whether the eye position of the examinee is correct.

[0042] In this embodiment, the first light source 101 is an SLED, and the wavelength of the light emitted by the SLED is 840 nm. The second light source 102 is an LED, and the wavelength of the light emitted by the LED is 630 nm. The 630 nm beam is a collimated beam. The collimating lens 104 is used to adjust the beam synthesized by the coupling fiber 103 into a straight beam.

[0043] In one embodiment of the present invention, please refer to Figures 1 to 4 together. The first 4f system includes a first front achromatic lens 105 and a first rear achromatic lens 106 arranged sequentially.

[0044] In this embodiment, the first 4f system is used to increase the peak power density of the emitted laser and reduce beam divergence; the first front achromatic lens 105 and the first rear achromatic lens 106 can reduce imaging distortion and improve the stability of light propagation; wherein, the focal length of the first front achromatic lens 105 is f1=25 cm, and the focal length of the first rear achromatic lens 106 is f2=12.5 cm.

[0045] In one embodiment of the present invention, please refer to Figures 3 and 4 together. The second beam splitter 201 is disposed between the first front achromatic lens 105 and the first rear achromatic lens 106.

[0046] In this embodiment, the function of the second beam splitter 201 is to split the beam that has passed through the first 4f system. One part of the beam continues to propagate along the original path to the wavefront aberration measurement device, while the other part of the beam is guided to the corneal topography measurement device. This design allows wavefront aberration and corneal topography measurements to be performed simultaneously, improving measurement efficiency.

[0047] In this embodiment, the second beam splitter 201 is a beam splitter with dimensions of 32×60 mm and a splitting ratio of 95:5. The reflected light is used in the corneal topography measurement device. The choice of beam splitter not only ensures effective beam splitting but also guarantees high precision in corneal topography measurement. After passing through the beam splitter, the reflected light is precisely guided to the corneal topography measurement device for constructing a corneal topography map. This design enables wavefront aberration measurement and corneal topography measurement to be performed efficiently and accurately in the same instrument, greatly improving the efficiency and accuracy of the measurement.

[0048] In one embodiment of the present invention, please refer to Figures 3 and 4 together. The second 4f system includes a second front achromatic lens 205 and a first rear achromatic lens 106. The first beam splitter 203 and the second beam splitter 201 are sequentially disposed between the second front achromatic lens 205 and the first rear achromatic lens 106.

[0049] In this embodiment, the second 4f system is also used to increase the peak power density of the emitted laser and reduce beam divergence. The combination of the second front achromatic lens 205 and the first rear achromatic lens 106 further reduces imaging distortion and ensures the stability of light propagation. In particular, the first beam splitter 203 and the second beam splitter 201 are cleverly positioned between the second front achromatic lens 205 and the second rear achromatic lens 202. This arrangement not only optimizes the optical path but also ensures the precise synchronization of wavefront aberration measurement and corneal topography measurement. The first beam splitter 203 plays a key role here, further subdividing the beam passing through the second 4f system. One part is guided to the wavefront aberrometer 304 for wavefront aberration measurement, while the other part continues to participate in the construction of the corneal topography map. This design not only improves the accuracy of the measurement but also greatly enhances the functionality of the instrument.

[0050] In this embodiment, depending on the size of the subject's cornea, the second 4f system can magnify or reduce the image formed by the wavefront aberration measuring device using different lens combinations, representing the magnification of the second 4f system. For species with smaller corneal diameters, the second 4f system is selected, such as: second 4f system lens combination f1=12.5 cm, f2=20 cm; for species with larger corneal diameters, the second 4f system is selected, such as: second 4f system lens combination f1=20 cm, f2=12.5 cm. This design allows the ocular parameter measuring instrument of the present invention to be applicable to subjects with different corneal sizes, further improving the instrument's applicability and flexibility. In specific implementation, the operator can flexibly adjust the lens combination in the second 4f system according to the subject's corneal size to achieve the best measurement effect.

[0051] In one embodiment of the present invention, the eye parameter measuring instrument further includes a first aperture 204. Please refer to FIG3. The first aperture 204 is disposed between the first beam splitter 203 and the second beam splitter 201. Alternatively, please refer to FIG1 and FIG4 together. The first aperture 204 is disposed between the second front achromatic lens 205 and the first beam splitter 203.

[0052] In this embodiment, the aperture size of the first aperture 204 is 3-7 mm. The setting of the first aperture 204 can effectively control the diameter of the light beam and the incident angle of the light, prevent interference from stray light, and thus improve the accuracy of the measurement. In specific implementation, the operator can flexibly select the position of the first aperture 204 according to actual needs to achieve the best measurement effect.

[0053] In another embodiment of the present invention, referring to Figures 1 and 2 together, the second beam splitter 201 is disposed between the first rear achromatic lens 106 and the Placido disc structure 401. This layout adjustment further optimizes the optical path design, making the measurement of wavefront aberration and the measurement of corneal topography smoother and less interfered with each other in the optical path, further improving the stability and accuracy of the measurement. At the same time, this design also facilitates independent debugging and optimization of the first 4f system and the corneal topography measurement device, improving the maintainability and performance of the instrument. In specific implementation, the operator can flexibly select the position of the second beam splitter 201 according to the actual measurement needs and scenarios to achieve the best measurement effect and instrument performance.

[0054] In another embodiment of the present invention, referring to Figures 1 and 2 together, the second 4f system includes a second front achromatic lens 205 and a second rear achromatic lens 202. A second beam splitter 201 is disposed between the second rear achromatic lens 202 and the Placido disc structure 401; a first beam splitter 203 is disposed between the second front achromatic lens 205 and the second rear achromatic lens 202. This design also aims to optimize the optical path layout and ensure the accuracy and synchronization of wavefront aberration measurement and corneal topography measurement. By placing the second beam splitter 201 between the second rear achromatic lens 202 and the Placido disc structure 401, the beam can be guided into the corneal topography measurement device more effectively, while reducing interference with the wavefront aberration measurement device. The placement of the first beam-splitting element 203 between the second front achromatic lens 205 and the second rear achromatic lens 202 ensures that the light beam is precisely split when passing through the second 4f system, guiding it to the wavefront aberrometer 304 and the corneal topography measuring device respectively, further improving measurement accuracy and instrument functionality. In practice, operators can flexibly adjust the component configuration of the second 4f system and the position of the beam-splitting element according to actual needs to achieve optimal measurement results and instrument performance.

[0055] In another embodiment of the present invention, the eye parameter measuring instrument further includes a first aperture 204. Please refer to Figures 1 and 4 together. The first aperture 204 is disposed between the second front achromatic lens 205 and the first beam splitter 203; or, please refer to Figure 2. The first aperture 204 is disposed between the first beam splitter 203 and the second rear achromatic lens 202.

[0056] In one embodiment of the present invention, referring to Figures 3 and 4 together, the third 4f system includes a third front achromatic lens 302 and a first rear achromatic lens 106, with a first beam splitter 203 and a second beam splitter 201 sequentially disposed between the third front achromatic lens 302 and the first rear achromatic lens 106. This design enables the third 4f system to not only effectively increase the peak power density of the emitted light and reduce beam divergence, but also further optimize the optical path layout through the ingenious arrangement of the first beam splitter 203 and the second beam splitter 201. The first beam splitter 203 plays a key role in re-splitting the beam, dividing the beam passing through the third 4f system into two parts: one part is guided to the wavefront aberration measurement device, and the other part is guided to the corneal topography measurement device, ensuring accurate synchronous measurement of wavefront aberration and corneal topography. At the same time, the combination of the third front achromatic lens 302 and the first rear achromatic lens 106 further reduces imaging distortion and improves the stability of light propagation, thereby improving the overall measurement accuracy and instrument performance.

[0057] In another embodiment of the present invention, please refer to Figures 1 and 2 together. The third 4f system includes a third front achromatic lens 302 and a second rear achromatic lens 202. The second beam splitter 201 is disposed between the second rear achromatic lens 202 and the Placido disc structure 401. The first beam splitter 203 is disposed between the third front achromatic lens 302 and the second rear achromatic lens 202.

[0058] In this embodiment, depending on the size of the subject's cornea, the third 4f system can magnify (or reduce) the image of Placido using different lens combinations. For species with smaller corneal diameters, the third 4f system is selected, such as a lens combination of f1=12.5 cm and f2=20 cm; for species with larger corneal diameters, the third 4f system is selected, such as a lens combination of f1=20 cm and f2=12.5 cm.

[0059] In one embodiment of the present invention, please refer to Figures 1 and 4 together. The eye parameter measuring instrument further includes a second aperture 301, which is disposed between the third front achromatic lens 302 and the first beam splitter 203.

[0060] In this embodiment, the aperture of the second aperture 301 is 3–7 mm. The second aperture 301 is mainly used to block reflected light from the anterior surface of the cornea, and can be finely adjusted according to whether it can completely block reflected light from the anterior surface of the cornea; the second aperture 301 can also be used to control the incident angle of light. In specific implementation, the operator can flexibly adjust the position and aperture size of the second aperture 301 according to the corneal characteristics of the examinee and the measurement requirements to achieve the best measurement effect.

[0061] In this embodiment, the first beam splitter 203 is a long-pass dichroic mirror with a size of 32 mm × 60 mm and a cutoff wavelength of 700 nm.

[0062] In one embodiment of the present invention, please refer to Figures 1 to 4 together. The eye parameter measuring instrument further includes a first bandpass filter 303, which is disposed between the wavefront aberrometer 304 and the third front achromatic lens 302.

[0063] In this embodiment, the first bandpass filter 303 is mainly used to allow light of a specific wavelength to pass through, in order to match the optical characteristics of the wavefront aberration meter 304. In this embodiment, the center wavelength of the first bandpass filter 303 is 800-850 nm. This design can effectively filter out stray light and improve the accuracy of wavefront aberration measurement. At the same time, the setting of the first bandpass filter 303 also enhances the instrument's anti-interference ability against ambient light, ensuring that stable measurement results can be obtained under different lighting conditions.

[0064] In this embodiment, the wavefront aberration meter 304 is an SH wavefront aberration meter. The SH wavefront aberration meter is used to receive light, analyze and utilize it to obtain wavefront aberration data of the subject's eye.

[0065] In one embodiment of the present invention, please refer to Figures 1 to 4 together. The eye parameter measuring instrument further includes a second bandpass filter 206, which is disposed between the image acquisition element 207 and the second front achromatic lens 205.

[0066] In this embodiment, the second bandpass filter 206 is mainly used to allow light of a specific wavelength to pass through, in order to match the optical characteristics of the corneal topography measurement device. In this embodiment, the center wavelength of the second bandpass filter 206 is 500-550 nm. This design can effectively filter out stray light and improve the accuracy of corneal topography measurement. At the same time, the setting of the second bandpass filter 206 also enhances the instrument's anti-interference ability against ambient light, further ensuring the stability and accuracy of the measurement.

[0067] In one embodiment of the present invention, the Placido disc structure 401 is provided with an illumination unit.

[0068] In this embodiment, the Placido disc structure 401 is a tool for evaluating ocular wavefront aberrations, and its design is based on a series of concentric rings. When these rings are projected onto the retina of the subject, the image of the rings is distorted due to ocular wavefront aberrations. By capturing and analyzing these distorted ring images through the image acquisition element 207, ocular wavefront aberration data can be calculated.

[0069] In one embodiment of the present invention, the Placido disc structure 401 can be designed with different numbers of rings to accommodate subjects with different corneal sizes. By adjusting the number of rings in the Placido disc structure 401, the coverage and resolution of the cornea being measured by the corneal topography measurement device can be changed. For subjects with larger corneas, a Placido disc structure 401 with more rings can be used to obtain more comprehensive corneal topography information; while for subjects with smaller corneas, a Placido disc structure 401 with fewer rings can be used to improve measurement accuracy and resolution.

[0070] For species with smaller corneal diameters, such as chickens or mice, due to their smaller eyes, a Placido ring with fewer rings is preferred, with 16 rings recommended to ensure clear projection of the rings onto the retina and accurate measurement results. For species with larger corneal diameters, such as humans or rabbits, due to their larger eyes, a Placido cone with more rings is preferred, with 32 or 36 rings recommended to provide more refined measurements and analysis.

[0071] Furthermore, the design of the Placido disc also takes into account the influence of the illumination unit. In this embodiment, a flexible LED, preferably green light, with a wavelength of 530 nm, is selected as the illumination unit to ensure that the circular image has sufficient brightness and contrast when projected onto the retina, thereby improving the accuracy and reliability of the measurement.

[0072] In this embodiment, the image acquisition element 207 adopts a CCD. The CCD acquires the image formed by the reflection of the cornea from the Placido disc structure 401, and analyzes and utilizes it to obtain the corneal topography data of the examinee.

[0073] The following testing process uses a human cornea as an example.

[0074] During the measurement process, the light intensity in the measurement room must be moderate, and the ambient lighting requirement for the instrument working area is 500–1000 Lux. Before conducting the test, based on the characteristics of the human cornea, the second 4f system in the wavefront aberration measuring device is selected, such as: lens combination f1=20 cm, f2=12.5 cm. In the corneal topography measuring device, a Placido cone is selected, with 36 rings, and the third 4f system is selected, such as: lens combination f1=20 cm, f2=12.5 cm. After selecting appropriate lens parameters and the Placido disc structure 401, the SLED emits an 840 nm beam and the LED emits a 630 nm beam. Both beams are transmitted into the coupling fiber 103 and then enter the first 4f system through the collimating lens 104. At this time, the examinee is instructed to open their eyes. When the light is clearly imaged on the examinee's retina and the focus is successful, the wavefront aberration image is captured by the wavefront aberrometer 304. At the same time, the illumination unit on the Placido disc structure 401 emits light, raising the examinee's upper eyelid to reduce the influence of eyelashes on corneal topography measurement. The CCD takes a picture and records the image. Afterwards, the system analyzes and integrates the obtained data to obtain the examinee's corneal topography and the wavefront aberration of the examinee's eye.

[0075] After the measurement of one eye is completed, the measurement of the other eye is performed. After the measurement of both eyes is completed, the test results are displayed on the screen interface and recorded to form a file of the examinee for later retrieval.

[0076] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention. [Simplified Explanation of the Diagram]

[0077] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those who are skilled in the art, other drawings can be obtained based on these drawings without making progressive changes.

[0078] Figure 1 is a schematic diagram of the structure of the eye parameter measuring instrument provided in an embodiment of the present invention;

[0079] Figure 2 is a schematic diagram of the structure of the eye parameter measuring instrument provided in an embodiment of the present invention;

[0080] Figure 3 is a schematic diagram of the structure of the eye parameter measuring instrument provided in an embodiment of the present invention;

[0081] Figure 4 is a schematic diagram of the structure of the eye parameter measuring instrument provided in the embodiment of the present invention.

Claims

1. An eye parameter measuring instrument, wherein, include: A wavefront pre-compensation device, comprising a compensation light source, a collimating lens, and a first 4f system arranged sequentially; A wavefront aberration measurement device, comprising a second 4f system, a first beam splitter, and a wavefront aberrometer arranged sequentially; a corneal topography measurement device, comprising a Placido disc structure, a third 4f system, a second beam splitter, and an image acquisition element arranged sequentially; the Placido disc structure faces the eye of the subject; wherein the optical paths of the first 4f system and the third 4f system intersect at the second beam splitter; the optical paths of the second 4f system and the third 4f system intersect at the first beam splitter.

2. The eye parameter measuring instrument as described in claim 1, wherein, The compensation light source includes a first light source, a second light source, and a coupling optical fiber. The beam emitted by the first light source and the beam emitted by the second light source are combined into a single beam through the coupling optical fiber. The first light source is used to provide light for the wavefront aberration measurement device. The second light source is used to determine whether the subject's eye position is correct.

3. The eye parameter measuring instrument as described in claim 1, wherein, The first 4f system includes a first front achromatic lens and a first rear achromatic lens arranged sequentially.

4. The eye parameter measuring instrument as described in claim 3, wherein, The second beam splitter is disposed between the first front achromatic lens and the first rear achromatic lens.

5. The eye parameter measuring instrument as described in claim 4, wherein, The second 4f system includes a second front achromatic lens and a first rear achromatic lens, with the first beam splitter and the second beam splitter sequentially disposed between the second front achromatic lens and the first rear achromatic lens.

6. The eye parameter measuring instrument as described in claim 5, wherein, The eye parameter measuring instrument also includes a first aperture, which is disposed between the first beam splitter and the second beam splitter, or the first aperture is disposed between the second front achromatic lens and the first beam splitter.

7. The eye parameter measuring instrument as described in claim 3, wherein, The second beam splitter is positioned between the first rear achromatic lens and the Placido disc structure.

8. The eye parameter measuring instrument as described in claim 7, wherein, The second 4f system includes a second front achromatic lens and a second rear achromatic lens, the second beam splitter being disposed between the second rear achromatic lens and the Placido disc structure; and the first beam splitter being disposed between the second front achromatic lens and the second rear achromatic lens.

9. The eye parameter measuring instrument as described in claim 8, wherein, The eye parameter measuring instrument also includes a first aperture stop, which is disposed between the second front achromatic lens and the first beam splitter; or, the first aperture stop is disposed between the first beam splitter and the second rear achromatic lens.

10. The eye parameter measuring instrument as described in claim 6, wherein, The third 4f system includes a third front achromatic lens and a first rear achromatic lens, with the first beam splitter and the second beam splitter sequentially disposed between the third front achromatic lens and the first rear achromatic lens.

11. The eye parameter measuring instrument as described in claim 6, wherein, The third 4f system includes a third front achromatic lens and a second rear achromatic lens, with the second beam splitter disposed between the second rear achromatic lens and the Placido disc structure; the first beam splitter is disposed between the third front achromatic lens and the second rear achromatic lens.

12. The eye parameter measuring instrument as described in claim 10 or 11, wherein, The eye parameter measuring instrument also includes a second aperture, which is positioned between the third front achromatic lens and the first beam splitter.

13. The eye parameter measuring instrument as described in claim 12, wherein, The eye parameter measuring instrument also includes a first bandpass filter, which is disposed between the wavefront aberrometer and the third front achromatic lens.

14. The eye parameter measuring instrument as described in claim 13, wherein, The parameter measuring instrument also includes a second bandpass filter, which is disposed between the image acquisition element and the second front achromatic lens.

15. The eye parameter measuring instrument as described in claim 1, wherein, The Placido disc structure includes an illumination unit.

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