Ophthalmic optical instrument and optical measurement system

Abstract

Provided are an ophthalmic optical instrument and an optical measurement system. The ophthalmic optical instrument comprises a visual target element, a first lens, a second lens, and a third lens. The first lens and the visual target element are arranged at intervals, and light emitted from the visual target element enters the first lens and exits as parallel light. The second lens is located on one side of the first lens away from the visual target element, and the described parallel light is converged to form an image after passing through the second lens. The third lens is located on one side of the second lens away from the first lens. The ophthalmic optical instrument further comprises a control element connected to the second lens and configured to control the movement of the second lens along its principal optical axis, such that the image formed by the second lens moves to at least one side of the third lens. The second lens in the ophthalmic optical instrument can move along its principal optical axis under the control of the control element, allowing the image formed by the second lens to move accordingly. Therefore, the movement range of the image formed by the second lens is relatively large, thereby improving the measurement range.

Description

Ophthalmic instruments and optical measurement systems

[0001] This application claims priority to Chinese Patent Application No. 2024101300187 filed on January 30, 2024, and the contents of the above-mentioned Chinese patent application disclosure are hereby incorporated by reference in their entirety as a part of this application. Technical Field

[0002] The embodiments of the present disclosure relate to an ophthalmic instrument and an optical measurement system. Background Art

[0003] Today, with the development and advancement of science and technology, modern life is closely intertwined with electronic products. As people's dependence on electronic products continues to grow, the incidence of myopia is rising. Generally, the development of myopia and presbyopia is closely related to visual function (i.e., vision) and accommodation required for close work, learning, and entertainment. Some studies have shown that the incidence of myopia in adolescents is as high as 90%. Furthermore, with the onset of presbyopia at an early age and an aging population, approximately one billion people worldwide are affected by presbyopia. Summary of the Invention

[0004] At least one embodiment of the present disclosure provides an ophthalmic optometry instrument and an optical measurement system.

[0005] At least one embodiment of the present disclosure provides an ophthalmic instrument, comprising a sight mark element, a first lens, a second lens, and a third lens, wherein the first lens is spaced apart from the sight mark element, and the light emitted by the sight mark element is incident on the first lens and then emitted as parallel light; the second lens is located on a side of the first lens away from the sight mark element, and the parallel light is converged into an image after passing through the second lens; the third lens is located on a side of the second lens away from the first lens, wherein the ophthalmic instrument further comprises a control element, which is connected to the second lens and is configured to control the second lens to move in the direction of its principal optical axis so that the image formed by the second lens moves on at least one side of the third lens.

[0006] For example, in the ophthalmic optometry instrument provided according to at least one embodiment of the present disclosure, the first lens is a collimating lens, the second lens includes a first positive lens, the third lens includes a second positive lens, the control element is configured to control the movement of the second lens between the first lens and the third lens, and the image plane of the second lens is located on the side of the second lens away from the sight mark element.

[0007] For example, in the ophthalmic instrument provided according to at least one embodiment of the present disclosure, there is a set position between the first lens and the third lens, and when the second lens moves between the set position and the third lens, the image plane of the second lens is located on the side of the third lens away from the sight element.

[0008] For example, in the ophthalmic optometry instrument provided according to at least one embodiment of the present disclosure, the focal length of the third lens is greater than the focal length of the second lens.

[0009] For example, according to at least one embodiment of the present disclosure, the ophthalmic instrument provided further includes a lens barrel, the lens barrel including a first end and a second end opposite to each other, the third lens is connected to the first end, and the central axis of the lens barrel coincides with the main optical axis of the third lens, and the distance between the first end and the second end is not greater than the focal length of the third lens.

[0010] For example, according to the ophthalmic optometry instrument provided by at least one embodiment of the present disclosure, the entrance pupil center of the eye to be inspected coincides with the back focus of the third lens.

[0011] For example, in the ophthalmic optometry instrument provided according to at least one embodiment of the present disclosure, the focal length of the first lens is greater than the focal length of the second lens.

[0012] For example, in the ophthalmic optometry instrument provided according to at least one embodiment of the present disclosure, the focal length of the second lens is 1 / 5 to 4 / 5 of the focal length of the first lens.

[0013] For example, in the ophthalmic optometry instrument provided according to at least one embodiment of the present disclosure, the distance between the first lens and the third lens is greater than the sum of the focal lengths of the second lens and the third lens.

[0014] For example, in the ophthalmic optometry instrument provided according to at least one embodiment of the present disclosure, the sight mark element is located at the front focus of the first lens.

[0015] For example, according to at least one embodiment of the present disclosure, the ophthalmic optometry instrument further includes a spectrometer and an automatic detection element, the spectrometer is located in the lens barrel, and there is an inclination angle between the main optical axis of the spectrometer and the focal plane of the third lens, and the inclination angle is 20° to 50°; the automatic detection element is configured to receive light from the spectrometer to detect the refractive power of the eye to be inspected.

[0016] For example, in the ophthalmic optometry instrument provided according to at least one embodiment of the present disclosure, the sight mark element includes an electronic display panel, which is configured to display a sight mark, and the sight mark includes at least one of Chinese characters, numbers and English letters, and the Chinese characters include at least one font.

[0017] For example, in the ophthalmic optometry instrument provided by at least one embodiment of the present disclosure, the shape and size of the sight mark are variable.

[0018] For example, according to the ophthalmic optometry instrument provided by at least one embodiment of the present disclosure, the electronic display panel is further configured to provide voice prompts.

[0019] For example, according to the ophthalmic optometry instrument provided by at least one embodiment of the present disclosure, the sight mark includes a plurality of sub-sight marks, and the plurality of sub-sight marks are arranged into M sub-sight mark rows, where M is a positive integer greater than 1, and in the arrangement direction of the M sub-sight mark rows, the height of the i-th sub-sight mark row, the distance between the i-th sub-sight mark row and the i+1-th sub-sight mark row, and the height of the i+1-th sub-sight mark row are distributed in geometric series, and i is a positive integer less than or equal to M-1.

[0020] For example, according to at least one embodiment of the present disclosure, the ophthalmic instrument provided by the ophthalmic instrument further includes: a body and a mount, wherein the body is cylindrical, the first lens, the second lens and the third lens are all located in the body, the body includes two opposite ends, the light emitted by the sight mark element enters the body through one end of the body close to the first lens, at least part of the lens barrel extends into the body from the other end of the body, and the body and the mount are rotatably connected so that the angle between the body and the setting surface of the mount can be adjusted.

[0021] For example, in the ophthalmic optometry instrument provided according to at least one embodiment of the present disclosure, the outer diameter of the lens barrel is smaller than the inner diameter of the body.

[0022] At least one embodiment of the present disclosure further provides an optical measurement system, comprising the ophthalmic instrument described in any of the above embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present disclosure, rather than limiting the present disclosure.

[0024] FIG1 is a schematic diagram of the structure of an ophthalmic optometry instrument provided by at least one embodiment of the present disclosure.

[0025] FIG2 is a schematic diagram of a sight mark provided by at least one embodiment of the present disclosure.

[0026] FIG3 is a light path diagram in which the image formed by the second lens is located between the second lens and the third lens in an embodiment of the present disclosure.

[0027] FIG4 is a light path diagram showing an embodiment of the present disclosure in which the image formed by the second lens is located on a side of the third lens away from the second lens.

[0028] FIG5 is a light path diagram of the ophthalmic instrument provided in an embodiment of the present disclosure when measuring hyperopia.

[0029] FIG6 is a light path diagram of the ophthalmic instrument provided by an embodiment of the present disclosure when measuring myopia. DETAILED DESCRIPTION

[0030] To make the purpose, technical solutions, and advantages of the embodiments of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0031] Unless otherwise defined, technical or scientific terms used in this disclosure should have the ordinary meanings understood by people with ordinary skills in the field to which this disclosure belongs. The words "first", "second" and similar terms used in this disclosure do not indicate any order, quantity or importance, but are simply used to distinguish different components. The words "include" or "comprising" and similar terms mean that the elements or objects preceding the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0032] Visual acuity refers to the ability of the retina to distinguish images. The quality of visual acuity is determined by the size of the retina's ability to distinguish images. Typically, visual acuity testing includes testing for near vision and testing for far vision. For example, the distance can be 0.25 meters or 5 meters. In some visual acuity testing processes, the visual acuity of the eye being tested may be measured when the retina is defocused, rather than when the sight mark is clearly imaged on the retina (i.e., when the sight mark is conjugated to the retina), so the test results are prone to errors. In addition, some commonly used visual acuity testing methods, such as pinhole visual acuity measurement, are used to detect potential best correctable visual acuity. From the perspective of geometric optics, the smaller the diameter of the pinhole, the more conducive it is to improving the accuracy of the test. However, since pinhole visual acuity measurement is mainly based on optical principles such as the focusing effect of the pinhole on light, this detection method may be affected by the diffraction of physical optics, making it difficult to measure the true potential best correctable visual acuity.

[0033] Nowadays, people look at close objects more often than distant objects. In some cases, when looking at close objects, they need to use their eyes to adjust in order to see clearly. When the method of eye adjustment is inappropriate, it will lead to blurred vision, visual fatigue, etc., and may also cause the occurrence of myopia or further deterioration of myopia. Accommodative power (or accommodative amplitude) is an important factor in measuring accommodative function. At present, the detection methods for accommodative power are relatively rough and less popular. For example, some subjective measurement methods such as the near-shift method, the far-shift method, and the negative lens method mainly rely on the subjective judgment and feedback of the subject to determine the measurement results, which are difficult to verify. At the same time, during the measurement process, the size of the visual angle corresponding to the sight mark will continue to change, and it cannot accurately stimulate the subject's accommodation. The measurement results of the near-shift method and the far-shift method are usually obtained based on the inverse of the working distance measured with a ruler, while the negative lens method is obtained by adding the measured negative lens power to the inverse of the working distance. The above-mentioned working distance is the distance between the eye being tested and the sight mark. However, the accuracy of the measurement results of these subjective measurement methods needs to be improved. For example, objective methods for measuring accommodation include dynamic retinoscopy, which usually requires experienced operators to perform. Automated refraction devices are generally used in laboratory research, so this method is less commonly used.

[0034] At least one embodiment of the present disclosure provides an ophthalmic instrument, comprising: an optometry element, a first lens, a second lens, and a third lens, wherein the first lens is spaced apart from the optometry element, and light emitted from the optometry element is incident on the first lens and then emitted as parallel light; the second lens is located on a side of the first lens away from the optometry element, and the parallel light is converged to form an image after passing through the second lens; the third lens is located on a side of the second lens away from the first lens, and the ophthalmic instrument further comprises a control element, which is connected to the second lens and is configured to control the second lens to move in the direction of its principal optical axis so that the image formed by the second lens moves on at least one side of the third lens.

[0035] In the ophthalmic instrument provided by the embodiments of the present disclosure, the second lens can be moved along its main optical axis under the control of the control element, so that the image formed by the second lens can move accordingly. For example, the image formed by the second lens can be moved on both sides of the third lens, such as being located on the side of the third lens away from the second lens. As a result, the image formed by the second lens (which serves as the "object" of the third lens) has a larger range of movement, thereby increasing the detection range and expanding the number of people to be detected.

[0036] The ophthalmic instrument and optical measurement system provided by the embodiments of the present disclosure are described below with reference to the accompanying drawings.

[0037] FIG1 is a schematic diagram of the structure of an ophthalmic optometry instrument provided by at least one embodiment of the present disclosure.

[0038] As shown in Figure 1, an ophthalmological instrument 01 includes an optotype element 100, a first lens 210, a second lens 220, and a third lens 230. The first lens 210 is spaced apart from the optotype element 100. Light emitted from the optotype element 100 enters the first lens 210 and exits as parallel light. The second lens 220 is located on the side of the first lens 210 away from the optotype element 100. The parallel light is converged into an image after passing through the second lens 220. The third lens 230 is located on the side of the second lens 220 away from the first lens 210. For example, when the ophthalmological instrument is used to examine a human eye, the human eye is located on the side of the third lens away from the second lens.

[0039] In some embodiments, as shown in FIG1 , the first lens 210 can be a collimating lens. When light emitted from the sight target element 100 passes through the first lens 210, the emitted light is parallel light. For example, the second lens 220 includes a first positive lens. After the parallel light is incident on the second lens 220, the image formed by the second lens 220 is located on an image plane 221 on the side of the second lens 220 away from the first lens 210 and at the back focus F'2 of the second lens 220. The distance between the image plane 221 and the second lens 220 remains constant, i.e., equal to the focal length of the second lens 220. For example, the third lens 230 includes a second positive lens. The image on the image plane 221 serves as the object of the third lens 230. After passing through the third lens 230, it is formed in the subject's eye 500 to stimulate accommodation.

[0040] For example, as shown in FIG1 , the ophthalmic instrument 01 further includes a control element 300 , which is connected to the second lens 220 and configured to control the movement of the second lens 220 in the direction of its principal optical axis O, so that the image formed by the second lens 220 moves on at least one side of the third lens 230, thereby providing different accommodation stimuli to the subject's eye. For example, the principal optical axis O of the second lens 220 may be parallel to the X-direction shown in FIG1 . For example, the control element 300 may be directly connected to the second lens 220 or connected via a connecting structure. The embodiments of the present disclosure do not limit the connection method between the control element 300 and the second lens 220, as long as the control element 300 can control the movement of the second lens 220. In some embodiments, the control element 300 may include a rotating wheel that an operator can rotate to control the movement of the second lens 220. In some embodiments, the control element 300 may include a motor that an operator can control to move the second lens 220.

[0041] As shown in FIG1 , the image formed by the second lens 220 moves on at least one side of the third lens 230. This means that, in the direction of the principal optical axis O of the second lens 220, the image formed by the second lens 220 moves on the side of the third lens 230 closer to the second lens 220, or moves on the side of the third lens 230 farther from the second lens 220. For example, when the second lens 220 moves away from the first lens 210, the image formed by the second lens 220 moves accordingly. For example, the image formed by the second lens 220 may be located on the side of the third lens 230 farther from the second lens 220, and then formed on the subject's eye 500 through the third lens 230 to test the visual acuity of the subject's eye 500. For example, when the third lens 230 forms a clear image on the retina of the subject, the best vision of the subject can be measured. When the second lens 220 moves in the direction away from the subject's eye, the second lens 220 moves to the critical position where the subject's eye 500 can see the image clearly and cannot see the image clearly, which corresponds to the adjustment far point; when the second lens 220 moves in the direction close to the subject's eye, the second lens 220 moves to the critical position where the subject's eye 500 can see the image clearly and cannot see the image clearly, which corresponds to the adjustment near point. The difference between the subject's refractive power corresponding to the adjustment far point and the refractive power corresponding to the adjustment near point is expressed as the subject's adjustment power.

[0042] As described above, compared with the situation in which the sight mark in a general sight mark element can only be located on the side of the third lens close to the sight mark element, in the ophthalmic instrument provided by the present invention, the image of the sight mark formed by the second lens can include two situations of being located on both sides of the third lens. In particular, when the image of the sight mark is located on the side of the third lens away from the second lens, the adjustment range of the image formed by the sight mark can be significantly improved, thereby improving the detection range of the ophthalmic instrument to adapt to a larger group of people to be detected.

[0043] For example, as shown in FIG1 , the control element 300 is configured to control the movement of the second lens 220 between the first lens 210 and the third lens 230, with the image plane 221 of the second lens 220 located on the side of the second lens 220 away from the sight element 100. For example, the second lens 220 can be moved toward the first lens 210. The embodiments of the present disclosure do not impose any restrictions on the minimum distance between the first lens 210 and the second lens 220, that is, as long as the parallel light emitted from the first lens 210 can be incident on the second lens 220 and form an image on the second lens 220. For example, the second lens 220 can also be moved toward the third lens 230, for example, until it is in contact with the third lens 230. In this case, the image formed by the second lens 220 is located on the side of the third lens 230 away from the second lens 220. For example, the image formed by the second lens 220 can serve as the "object" of the third lens 230. This is unaffected by the position and thickness of the third lens 230 (e.g., the size of the third lens 230 along its principal optical axis). It can be located on either the side of the third lens 230 that is closest to the second lens 220 or on the side of the third lens 230 that is further away from the second lens 220. Therefore, the image formed by the second lens 220 has a larger range of movement, thereby increasing the detection range. Furthermore, compared to some solutions that directly move the sight mark for detection, the embodiments of the present disclosure perform measurements by moving the image formed by the second lens 220, making operation easier and smoother.

[0044] As shown in Figure 1, the front focus F1 of the first lens 210 is located on the side away from the eye 500 to be inspected, and its back focus is located on the side closer to the eye 500 to be inspected. The front focus F1 of the second lens 220 is located on the side away from the eye 500 to be inspected, and its back focus is located on the side closer to the eye 500 to be inspected. The front focus F'3 of the third lens 230 is located on the side away from the eye 500 to be inspected, and its back focus F'3 is located on the side closer to the eye to be inspected. In some embodiments, a cylindrical lens may be provided at the back focus F'3 of the third lens 230 to correct astigmatism, thereby measuring the best corrected visual acuity that can be achieved from refractive error to full correction. For example, during a follow-up measurement of a subject, if the best visual acuity obtained in a second measurement decreases, and the same best visual acuity is now measured by changing the position of the second lens 220 (and thereby changing the position of the image formed by the second lens 220), the decrease in best visual acuity in the second measurement may be due to a change in refractive power caused by defocus of the subject's refractive system. For example, when the best visual acuity obtained by the secondary measurement decreases, and the same best visual acuity cannot be measured by changing the position of the second lens 220 (and thus changing the position of the image formed by the second lens 220), the decrease in the subject's best visual acuity may be due to an organic eye disease.

[0045] For example, as shown in FIG1 , a set position A1 is defined between the first lens 210 and the third lens 230. When the second lens 220 moves between the set position A1 and the third lens 230, the image plane 221 of the second lens 220 is located on the side of the third lens 230 that is away from the sight element 100. For example, the set position A1 is located between the second lens 220 and the third lens 230. Since the image formed by the second lens 220 is located at the back focus of the second lens 220, when the distance between the second lens 220 and the third lens 230 is less than the focal length of the second lens 220, the image formed by the second lens 220 is located on the side of the third lens 230 that is away from the second lens 220. Therefore, the distance between the set position A1 and the third lens 230 can be equal to (or less than) the focal length of the second lens 230.

[0046] For example, as shown in FIG1 , the focal length f3 of the third lens 230 is greater than the focal length f2 of the second lens 220. That is, when the second lens 220 is moved close to the third lens 230, the image formed by the second lens 220 can be located within the focal length range of the third lens 230. For example, when the second lens 230 is located between the set position A1 and the third lens 230, the image formed by the second lens 230 is located on the side of the third lens 230 away from the second lens 220. In this case, the image formed by the second lens 220 serves as a "virtual object" of the third lens 230, and this "virtual object" is located within the focal length range of the third lens 230. As a result, a real image can be formed through the third lens 230, allowing the subject's eye 500 to see the real image. In the embodiments of the present disclosure, "an object is located within the focal length range of a lens" means that the distance between the object and the lens is no greater than the focal length of the lens.

[0047] For example, as shown in FIG1 , the entrance pupil center of the eye 500 to be inspected coincides with the rear focus F'3 of the third lens 230. Similar to a telecentric optical measurement system, the pupil of the subject acts as an aperture stop, and the size of the image ultimately formed on the subject's retina will remain unchanged during the movement of the second lens 220 along its principal optical axis O. Compared to some optical measurement systems, such as the Badal Optometer, whose rear focus is located at the front focus of the eye 500 to be inspected, and the Nagel Optometer, whose rear focus is located at the nodal point of the eye 500 to be inspected, these two detection systems ensure that the size of the image formed by the lens on the subject's retina remains unchanged, provided that the subject's retina is clear. Therefore, these systems have certain limitations and are difficult to fully guarantee during actual measurement. Therefore, in the ophthalmic instrument provided by the embodiment of the present disclosure, since the back focus F'3 of the third lens 230 is located at the center of the subject's entrance pupil, the image formed on the subject's retina can maintain a constant size regardless of whether the subject's retina is clear or blurred.

[0048] At the same time, as shown in Figure 1, when the entrance pupil center of the eye 500 to be inspected coincides with the back focus F'3 of the third lens 230, the angle of view of the image formed by the second lens 220 through the third lens 230 to the eye 500 to be inspected remains unchanged. Compared to some measurement methods, for example, for the approach method, as the sight mark moves closer to the eye to be inspected, the angle of view of the sight mark to the eye to be inspected increases. For example, in the minus lens method, as the minus lens power increases, the angle of view of the sight mark to the eye to be inspected decreases. Since the size of the sight mark is the main factor affecting the measurement of accommodation power, it is extremely important for measurement accuracy to keep the angle of view of the image formed by the sight mark relative to the eye to be inspected (which is slightly larger than the best visual acuity of the eye to be inspected) unchanged when performing the measurement.

[0049] For example, as shown in FIG1 , the ophthalmic instrument 01 further includes a lens barrel 400, which includes a first end 401 and a second end 402 opposite each other. The third lens 230 is connected to the first end 401, and the central axis of the lens barrel 400 coincides with the principal optical axis of the third lens 230. The distance between the first end 401 and the second end 402 is no greater than the focal length f3 of the third lens 230. For example, the third lens 230 can be fixedly connected to the first end 401 of the lens barrel 400, and the end surface of the second end 402 of the lens barrel 400 can serve as a detection surface. The detection surface is perpendicular to the extension direction of the principal optical axis O of the third lens 230, and the back focus F'3 of the third lens 230 is located on the detection surface. For example, the detection surface can be a virtual surface rather than an actual plane in the lens barrel 400. For example, during the detection process, the lens barrel 400 can reduce the influence of gas, impurities, etc. on the detection optical path, thereby improving detection accuracy. For example, the distance between the first end 401 and the second end 402 of the lens barrel 400 can be equal to the focal length of the third lens 230, so that the entrance pupil center of the subject's eye 500 can coincide with the back focus F'3 of the third lens 230 and be located on the detection surface of the second end 402 of the lens barrel 400, thereby facilitating operation. In some embodiments, the distance between the first end 401 and the second end 402 of the lens barrel 400 can also be less than the focal length of the third lens 230. In this case, the detection surface for the subject's eye 500 is located outside the lens barrel 400. For example, a position mark can be provided on the outside of the lens barrel 400. When performing the test, the entrance pupil center of the subject can be located at the position of the mark.

[0050] For example, as shown in FIG1 , the distance L6 between the first lens 210 and the third lens 230 is greater than the sum of the focal length f2 of the second lens 220 and the focal length f3 of the third lens 230. For example, when testing a patient with hyperopia, when the second lens 220 moves away from the third lens 230, the far point of the patient's eye accommodation is located outside the focal length range of the third lens 230. Therefore, by ensuring that the distance L6 between the first lens 210 and the third lens 230 is greater than the sum of the focal length f2 of the second lens 220 and the focal length f3 of the third lens 230, support can be provided for testing patients with hyperopia, thereby detecting potential hyperopia in the patient. For example, when a patient has potential hyperopia, they require more accommodation than their emmetropic or corrected eye and are more susceptible to visual fatigue. For example, the difference between L6 and f2+f3 can be set according to design requirements, for example, it can be 30mm to 90mm, such as 40mm, 50mm, 60mm or 70mm, so as to expand the detection needs for hyperopic patients.

[0051] For example, as shown in FIG1 , the sight element 100 is located at the front focus F1 of the first lens 210. For example, the first lens 210 is a collimating lens, and the light emitted from the sight element 100 is refracted by the first lens 210 and then emitted as parallel light. Therefore, the image formed by the first lens 210 on the sight element 100 will be located at infinity.

[0052] For example, as shown in FIG1 , the focal length f1 of the first lens 210 is greater than the focal length f2 of the second lens 220. Since the second lens 220 is a first positive lens, the refractive power of the first lens 210 can be smaller than that of the second lens 220. This configuration allows the size of the image formed by the second lens 220 to be smaller than the size of the sight mark in the sight mark element 100, thereby ensuring that the size of the image entering the subject's eye 500 is appropriate and expanding the subject's vision detection range. In some embodiments, the refractive power of the first lens 210 can be 5 to 15D, such as 8D, 10D, 12D, 13D, or 15D. In some embodiments, the refractive power of the second lens 210 can be 10 to 30D, such as 12D, 15D, 18D, 20D, 25D, 28D, or 30D. For example, the ratio of the refractive power of the first lens 210 to the refractive power of the second lens 210 can be 0.2 to 0.8, such as 0.3, 0.5, 0.6, or 0.8. For example, the focal length f2 of the second lens 220 can be 1 / 5 to 4 / 5 of the focal length f1 of the first lens 210, such as 1 / 4, 1 / 3, or 1 / 2, although this is not limited in the embodiments of the present disclosure. For example, when the refractive power of the first lens 210 is 1 / 2 of the refractive power of the second lens 220, the image of the sight mark element 100 formed by the second lens 220 will be reduced to 1 / 2 of its original size.

[0053] For example, as shown in FIG1 , the sight mark element 100 may include an electronic display panel, and the electronic display panel is configured to display a sight mark 110 (see FIG2 ). For example, the sight mark element 100 may also include a controller to control the electronic display panel to make it more intelligent. For example, when the electronic display panel is used to display the sight mark 110, the electronic display panel can adjust the display screen in a timely manner, for example, it can adjust the display brightness for different application environments and for different subjects, so that the display can be more flexible. In addition, unlike some printed materials used for vision testing, the intensity distribution of the display screen of the electronic display panel is a line spread function, such as the electronic screens seen in daily life, which is more in line with the eye adjustment situation of modern people when using electronic products.

[0054] For example, as shown in FIG2 , the shape and size of the sight mark 110 displayed on the electronic display panel can be changed, thereby providing options for clinical applications and preventing the subject from memorizing the sight mark, thereby verifying whether the subject can actually see the sight mark clearly, thereby improving the accuracy of the test.

[0055] In some embodiments, as shown in FIG1 , when measuring the spectacle accommodation, the eye 500 to be inspected wears corrective hyperopia frame glasses, and the surface of the corrective hyperopia frame glasses is placed on the measuring plane 150. The size of the selected sight mark may be slightly larger than the size of the sight mark corresponding to the best corrected visual acuity of the eye to be inspected. Then, the second lens 220 is gradually moved away from the subject, and the subject is instructed to change the sight mark in the sight mark element 100 from being able to see the sight mark clearly to being blurred, and continuing to be blurred until the sight mark in the sight mark element 100 cannot be read correctly, to prevent the subject from remembering it. Then, the second lens 220 is slightly moved closer until the subject can correctly read the sight mark. At this time, the position of the image plane of the second lens 220 is the far point of the eye to be inspected. Next, the second lens 220 is gradually moved closer, and the subject is instructed to change the sight mark in sight element 100 from the point at which they can clearly see it until it becomes blurry and remains blurry, to prevent them from memorizing it. The sight mark is then slightly moved farther away until the subject can correctly read it. The sight mark at this point represents the near point of the subject's eye 500. The difference between the refractive power of the far point and the near point of the subject's eye 500 can be used to determine the subject's true accommodative power. For example, during a follow-up examination of the subject, if the far point becomes closer, the subject's eye 500 is myopic; if the near point becomes farther away, presbyopia is worsening; and if the far and near points are closer together, accommodative power is decreased.

[0056] In some implementations, as shown in Figures 1 and 2, when measuring the ocular accommodation of the subject, when the subject's eye 500 is emmetropic or wearing contact lenses, the center of the entrance pupil of the subject's eye 500 (i.e., 3 mm behind the cornea) is located on the measurement plane 150, and the above-mentioned measurement process is performed to measure the accommodation of the subject's eye.

[0057] In some embodiments, as shown in FIG1 , the electronic display panel is further configured to provide voice prompts. For example, the electronic display panel may display a gradually approaching display image (e.g., the optotype and / or the image surrounding the optotype gradually moves closer), and simultaneously, the electronic display panel may provide voice prompts, such as vocal stimulation, to indicate that the optotype and the image are approaching, thereby stimulating the subject's proximal accommodation and thereby measuring a maximum value.

[0058] FIG2 is a schematic diagram of a sight mark provided by at least one embodiment of the present disclosure.

[0059] For example, as shown in FIG2 , the sight mark 110 may include at least one of Chinese characters, numbers, and English letters. For example, the measurement of the subject's vision may fall within the scope of psychophysical science, which targets not only form sense but also perception. For example, the sight mark 110 may include a combination of Chinese characters and English letters, or a combination of numbers and English letters, but the embodiments of the present disclosure are not limited thereto. For example, the sight mark 110 may include English letters such as C, D, H, K, N, O, R, S, V, and Z, but are not limited thereto. For example, the sight mark 110 may include numbers such as 2, 3, 4, 5, 6, 7, 8, and 9, but are not limited thereto. For example, the sight mark shown in FIG2 includes a combination of multiple numbers and multiple English letters "E", and the multiple English letters "E" are arranged in different directions, for example, in different directions relative to the Y direction shown in FIG2 . Multiple numbers are located on the same side of multiple English letters, but the embodiments of the present disclosure are not limited thereto. In some embodiments, multiple numbers and multiple English letters can be arranged alternately, for example, a row of numbers can be provided between two adjacent rows of English letters, or a column of numbers can be provided between two adjacent columns of English letters, so as to achieve a more diverse arrangement. In some embodiments, the sight mark 110 can include multiple Chinese characters, and the multiple Chinese characters can have different fonts. For example, the multiple English letters in the sight mark 110 can also be different, which is beneficial to improve the detection accuracy. For example, the ophthalmic optometry instrument provided in the embodiment of the present disclosure also includes an intelligent processor, which can be bound to an APP (application) to automatically judge the response results of the subject.

[0060] For example, as shown in FIG2 , the sight mark 110 includes a plurality of sub-sight marks 11, and the plurality of sub-sight marks 11 are arranged into M sub-sight mark rows R, and the M sub-sight marks R are arranged along the Y direction shown in FIG2 , where M is a positive integer greater than 1. For example, in the Y direction, the height P1 of the i-th sub-sight mark row R, the distance P2 between the i-th sub-sight mark row R and the i+1-th sub-sight mark row R, and the height P3 of the i+1-th sub-sight mark row R are distributed in a geometric series, where i is a positive integer less than or equal to M-1. For example, the distance P2 = P1 / K1, and the distance P3 = P1 / K2. The above-mentioned geometric series distribution means that the values ​​of P1 and P2 are geometrically distributed, and the values ​​of P1 and P3 are geometrically distributed. For example, the distance P2 = P1 / 10 1 / 20 (approximately P1 / 1.122), distance P3 = P1 / 10 1 / 10 (approximately P1 / 1.2589), thereby making the sizes of the multiple sub-visual marks R and the distances in the Y direction regularly distributed.

[0061] In some embodiments, as shown in FIG1 , the ophthalmic instrument 01 can also measure the subject's accommodation speed, that is, measure the ratio between the time required to adjust from the subject's far point to its near point and the accommodation force. In some embodiments, the ophthalmic instrument 01 can also measure the subject's accommodation flexibility, that is, the frequency of effective changes in accommodation between the subject's far point and near point within a certain period of time; or, the frequency of effective changes in accommodation between 5 meters and 0.3 meters within a certain period of time. In some embodiments, the ophthalmic instrument 01 can also measure the subject's accommodation persistence, that is, measure the duration of time that the subject's eye 500 can clearly see the sight mark at the near point. Of course, the ophthalmic instrument 01 can also have other measurement functions, which are not limited by the embodiments of the present disclosure.

[0062] For example, as shown in FIG1 , the ophthalmic instrument 01 further includes a spectroscope 600 and an automatic detection element 700. The spectroscope 600 is located in the lens barrel 400, and the principal optical axis of the spectroscope 600 is tilted at an angle β to the focal plane of the third lens 230. For example, when the image formed by the third lens 230 is incident on the eye to be inspected 500, the spectroscope 600 transmits part of the light and reflects part of the light. For example, part of the light is incident on the eye to be inspected 500 along the principal optical axis of the third lens 230 for subjective detection, while part of the light can be reflected by the spectroscope 600 to the automatic detection element 700. For example, the automatic detection element 700 is configured to receive light from the spectroscope 600 to detect the diopter of the eye to be inspected 500, thereby enabling objective measurement. For example, the automatic detection element 700 may be an autorefractor, but is not limited thereto. With this arrangement, subjective and objective tests can be performed on the subject's refractive power. By comparing the subjective and objective test results, the accommodation advance or accommodation lag during the subjective test can be obtained, and the value of the accommodation advance or accommodation lag can be obtained. Therefore, a more reasonable vision adjustment plan can be formulated for the subject based on the subjective and objective test results.

[0063] In some embodiments, as shown in FIG1 , the pupil size of the subject's eye can be measured using a spectroscope 600. The depth of field of the subject's eye can be estimated by combining the subject's pupil size and vision test results. For example, in other embodiments, the pupil size of the subject's eye can be directly measured using a spectroscope 600 to estimate the depth of field of the subject's eye.

[0064] For example, as shown in FIG1 , the inclination angle β between the principal optical axis of the beam splitter 600 and the focal plane of the third lens 230 may be 25° to 50°, such as 30°, 35°, 40° or 45°, so that the light reflected and transmitted by the beam splitter 600 can be reasonably distributed, that is, while satisfying subjective measurement, sufficient light can also be emitted to the automatic detection element 700.

[0065] For example, as shown in FIG1 , the ophthalmic instrument 01 further includes a body 800 and a mount 900. The body 800 is cylindrical in shape, with the first lens 210, the second lens 220, and the third lens 230 all located within the body 800. The body 800 includes two opposing ends (e.g., one end 801 and the other end 802). Light emitted from the sight mark element 100 enters the body 800 through the end 801 of the body 800 proximate to the first lens 210. At least a portion of the lens barrel 400 extends into the body 800 from the other end 802 of the body 800. For example, the inner diameters of the first lens 210, the second lens 220, and the third lens 230 are all smaller than the inner diameter of the body 800, so that the body can provide a sufficiently large space for light propagation. For example, the first lens 210 can be fixedly connected to the body 800. The sight mark element 100 may have a display portion, and the display portion is located within the minimum overlap area between the sight mark element 100 and the lens barrel 400 in the X direction, thereby ensuring that light emitted from the sight mark of the sight mark element 100 can reach the first lens 210. For example, the lens barrel 400 may be fixedly connected to the body 800, with a portion of the lens barrel 400 located within the body 800, and the third lens 230 connected to the first end 401 of the lens barrel 400 to facilitate receiving light from the image formed by the second lens 220; another portion of the lens barrel 400 is located outside the body 800, so that its second end 402 matches the subject's eye 500, thereby facilitating the subject's eye 500 to reach a suitable detection position.

[0066] For example, as shown in Figure 1, the body 800 and the mount 900 are rotatably connected, allowing the angle between the body 800 and the mounting surface of the mount 900 to be adjustable. For example, the mounting surface of the mount 900 can be a horizontal plane, with the bottom surface of the mount 900 parallel to the mounting surface. A rotation axis is defined between the body 800 and the mount 900, allowing the body 800 to rotate about the axis, thereby changing the angle between the body 800 and the design surface. For example, the angle can be between 25° and 50°, such as 30°, 35°, 40°, or 45°. For example, subjects may differ in height, physique, and other aspects. Therefore, the angle between the body 800 and the design surface may vary for different subjects, such as to suit the angle at which the subject views close objects. For example, for shorter subjects, the angle may be appropriately reduced so that the subject can see the final image of the sight mark formed by each lens along direction X.

[0067] For example, as shown in FIG1 , the outer diameter W2 of the lens barrel 400 is smaller than the inner diameter W1 of the body 800. For example, the outer diameter W2 of the lens barrel 400 can be 1 / 4 to 2 / 3 of the inner diameter W1 of the body 800, such as 1 / 3 or 1 / 2. This arrangement makes it easy to align the eye being examined with the lens barrel 400, thereby achieving a good optical effect. The lens barrel 400 is lightweight and easy to use, and its shape and size meet current clinical use requirements and are highly acceptable. For example, the lens barrel 400 also includes a fourth lens 240 located at its second end 402, and the ophthalmic instrument 01 also includes a fifth lens 250 located at the first end 801 of the body 800. For example, the fourth lens 240 and the fifth lens 250 can both be plane lenses, and the fourth lens 240 and the fifth lens 250 can be used to seal the ophthalmic instrument 01 for dust prevention.

[0068] FIG3 is an optical path diagram in which the image formed by the second lens is located between the second lens and the third lens in an embodiment of the present disclosure; FIG4 is an optical path diagram in which the image formed by the second lens is located on the side of the third lens away from the second lens in an embodiment of the present disclosure; FIG5 is an optical path diagram in which the ophthalmic instrument provided in an embodiment of the present disclosure is used to measure hyperopia; FIG6 is an optical path diagram in which the ophthalmic instrument provided in an embodiment of the present disclosure is used to measure myopia. For example, FIG3 to FIG6 show the front focus F1 and the back focus F'1 of the first lens 210, the front focus F2 and the back focus F'2 of the second lens 220, and the front focus F3 and the back focus F'3 of the third lens 230. It should be noted that the relative positional relationships of the various lenses and the sight mark elements shown in FIG3 to FIG6 are only schematically shown, and the embodiments of the present disclosure do not limit the specific structures of the various lenses and the sight mark elements.

[0069] For example, as shown in Figure 3, the visual target element 100 serves as a physical object. Light emitted from the visual target element 100 is incident on the first lens 210, where it forms an image at infinity. Parallel light emitted from the first lens 210 is incident on the second lens 220, where it forms a real image at its back focus F'2, located in an image plane 221. Because the image plane 221 is located at the front focus F3 of the third lens 230, the image formed by the second lens 220 serves as the physical object of the third lens 230. Therefore, the image is formed at infinity through the third lens 230, and the back focus F'3 of the third lens 230 is located in a measurement plane 150. The eye being examined coincides with the back focus F'3 of the third lens 230. At this point, the eye being examined is as if looking at a distant object, and the accommodation demand on the eye is zero. For example, when the image formed by the second lens 220 gradually approaches the third lens 230, the image formed by the third lens 230 gradually approaches the subject's eye, thereby increasing the adjustment requirements for the subject's eye. At this time, the subject needs to use an equal amount of adjustment to see the image formed by the third lens 230 clearly.

[0070] For example, as shown in Figure 4, the distance between the second lens 220 and the third lens 230 is less than the focal length of the second lens 220. In this case, the image formed by the second lens 220 is located on the side of the third lens 230 away from the second lens 220 and is located in image plane 221. Image plane 221 acts as a virtual object of the third lens 230 and forms a real image 231 through the third lens 230. This real image 231 is located on the side of the third lens 230 away from the second lens 220 and is located between image plane 221 and the third lens 230. The subject's eye coincides with the back focus F'3 of the third lens 230. At this point, the subject's eye is like looking at a close object and requires accommodation to see clearly. For example, the movement distance of the image formed by the second lens 220 is linearly related to the subject's accommodation requirement. As the movement distance of the image formed by the second lens 220 decreases, the subject's accommodation requirement increases, thereby facilitating the accuracy of the test results.

[0071] For example, as shown in FIG5 , the visual target element 100 serves as a physical object. Light emitted from the visual target element 100 is incident on the first lens 210, and is imaged at infinity by the first lens 210. Parallel light emitted from the first lens 210 is incident on the second lens 220, and is imaged by the second lens 220 at its rear focus F'2, i.e., located in the image plane 221. The image formed by the second lens 220 serves as a physical object for the third lens 230. Because this physical object is located outside the front focus F3 of the third lens 230 (i.e., on the side of the front focus F3 of the third lens 230 closer to the second lens 220), the image formed by the third lens 230 is located behind the retina of the eye being examined and is imaged on the retina of the hyperopic patient through the refractive system of the hyperopic eye.

[0072] For example, as shown in Figure 6 , the visual target element 100 serves as a physical object. Light emitted from the visual target element 100 is incident on the first lens 210, where it forms an image at infinity. Parallel light emitted from the first lens 210 is incident on the second lens 220, where it forms a real image at its rear focus F'2, located in the image plane 221. The image formed by the second lens 220 serves as a physical object for the third lens 230. Because this physical object is located within the front focus F3 of the third lens 230 (i.e., on the side of the front focus F3 of the third lens 230 that is closest to the third lens 230), the virtual image 232 formed by the third lens 230 is located in front of the retina of the subject's eye. The subject's eye, located at the measurement plane 150, appears to be viewing a near object.

[0073] At least one embodiment of the present disclosure further provides an optical measurement system, including the ophthalmic instrument described in any of the aforementioned embodiments. Because the optical measurement system includes the ophthalmic instrument described in any of the aforementioned embodiments, it also possesses the technical benefits provided by the aforementioned ophthalmic instruments, and will not be further elaborated here.

[0074] For example, the optical measurement system provided by at least one embodiment of the present disclosure may further include some control components, such as a remote control for controlling the display of an optotype element. The remote control can be used to control the optotype element to display multiple rows of sub-optotypes 11 as shown in FIG2 , or to control the optotype element 110 to display a single row of optotypes, or to control the optotype element 110 to display a single sub-optotype 11. For example, the remote control can also be used to control the background color of the optotype element 110 to change, such as by changing the background color of some sub-optotypes 11 to red, some to green, and some to white, to determine whether the subject's current refractive correction is overcorrected or undercorrected. For example, the remote control can also control the color of the sub-optotype 11 shown in FIG2 to swap with the color of its background, such as by changing the sub-optotype 11 shown in FIG2 to white and its background to black, to determine whether the subject has decreased vision due to turbidity of the refractive medium, such as cataracts. For example, the remote control may also be used to control the visual target element 110 to display an astigmatism disk to determine whether there is astigmatism. The embodiments of the present disclosure do not limit the control function of the remote control.

[0075] For example, in the optical measurement system provided by at least one embodiment of the present disclosure, the control component may further include a controller connected to the automatic ophthalmometer, for controlling the input and recording the name, time, number, etc. of the subject, and can realize one-click automatic ophthalmology and save, so as to record the results of each follow-up of the subject and display them as an ophthalmology curve, so as to be compared with the subjective measurement value. The embodiments of the present disclosure do not limit the function of the controller.

[0076] There are a few points to note:

[0077] (1) The drawings of the embodiments of the present disclosure only involve structures related to the embodiments of the present disclosure, and other structures can refer to general designs.

[0078] (2) In the absence of conflict, features in the same embodiment and different embodiments of the present disclosure may be combined with each other.

[0079] The foregoing description is merely an exemplary embodiment of the present disclosure and is not intended to limit the scope of protection of the present disclosure. The scope of protection of the present disclosure is determined by the appended claims.

Claims

1. An ophthalmic instrument comprising: sight mark element; a first lens, spaced apart from the sight mark element, wherein light emitted from the sight mark element is incident on the first lens and then emitted as parallel light; a second lens, located on a side of the first lens away from the sight mark element, wherein the parallel light is converged into an image after passing through the second lens; a third lens located on a side of the second lens away from the first lens, The ophthalmic instrument further includes a control element, which is connected to the second lens and is configured to control the second lens to move in the direction of its main optical axis so that the image formed by the second lens moves on at least one side of the third lens.

2. The ophthalmic instrument according to claim 1, wherein: The first lens is a collimating lens, the second lens includes a first positive lens, and the third lens includes a second positive lens. The control element is configured to control the second lens to move between the first lens and the third lens, and the image plane of the second lens is located on a side of the second lens away from the sight mark element.

3. The ophthalmic instrument according to claim 2, wherein: There is a set position between the first lens and the third lens, When the second lens moves between the set position and the third lens, the image plane of the second lens is located on a side of the third lens away from the sight mark element.

4. The ophthalmic instrument according to claim 3, wherein: The focal length of the third lens is greater than the focal length of the second lens.

5. The ophthalmic optometry instrument according to any one of claims 2 to 4, further comprising a lens barrel, wherein: The lens barrel includes a first end and a second end opposite to each other, the third lens is connected to the first end, and the central axis of the lens barrel coincides with the main optical axis of the third lens, and the distance between the first end and the second end is no greater than the focal length of the third lens.

6. The ophthalmic instrument according to claim 5, wherein: The entrance pupil center of the eye to be inspected coincides with the back focus of the third lens.

7. The ophthalmic instrument according to any one of claims 1 to 6, wherein: The focal length of the first lens is greater than the focal length of the second lens.

8. The ophthalmic instrument according to claim 7, wherein: The focal length of the second lens is 1 / 5 to 4 / 5 of the focal length of the first lens.

9. The ophthalmic instrument according to any one of claims 1 to 8, wherein: A distance between the first lens and the third lens is greater than a sum of a focal length of the second lens and a focal length of the third lens.

10. The ophthalmic instrument according to any one of claims 1 to 9, wherein: The sight target element is located at the front focus of the first lens.

11. The ophthalmic instrument according to claim 6, further comprising: A beam splitter is located in the lens barrel, wherein a main optical axis of the beam splitter and the focal plane of the third lens have an inclination angle of 25° to 50°; The automatic detection element is configured to receive the light from the spectroscope to detect the refractive power of the eye to be inspected.

12. The ophthalmic instrument according to any one of claims 1 to 11, wherein: The optotype element includes an electronic display panel configured to display an optotype. The sight signs include at least one of Chinese characters, numbers and English letters, and the Chinese characters include at least one font.

13. The ophthalmic instrument according to claim 12, wherein: The shape and size of the sight mark can vary.

14. The ophthalmic instrument according to claim 12 or 13, wherein: The electronic display panel is further configured to provide voice prompts.

15. The ophthalmic instrument according to any one of claims 12 to 14, wherein: The optotype includes a plurality of sub-optotypes, and the plurality of sub-optotypes are arranged into M sub-optotype rows, where M is a positive integer greater than 1. In the arrangement direction of the M sub-visual mark rows, the height of the i-th sub-visual mark row, the distance between the i-th sub-visual mark row and the i+1-th sub-visual mark row, and the height of the i+1-th sub-visual mark row are distributed in a geometric series, where i is a positive integer less than or equal to M-1.

16. The ophthalmic instrument according to claim 5 or 6, further comprising: The body and the mount, wherein the body is cylindrical, the first lens, the second lens, and the third lens are all located in the body, the body includes two opposite ends, the light emitted by the sight mark element enters the body through the end of the body close to the first lens, and at least a portion of the lens barrel extends into the body from the other end of the body. The fuselage is rotatably connected to the seat frame so that the angle between the fuselage and the erection plane of the seat frame can be adjusted.

17. The ophthalmic instrument according to claim 16, wherein: The outer diameter of the lens barrel is smaller than the inner diameter of the body.

18. An optical measurement system comprising the ophthalmic instrument according to any one of claims 1 to 17.

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