Optometry device and optometry method

Abstract

The application provides an optometry device and an optometry method. The optometry device comprises a first light source, a light splitting assembly, a first photodetector, a processor and a refractive correction assembly. The first light source is configured to emit light to an eyeball of a subject. The light splitting assembly is arranged on a light path from the first light source to the eyeball. The light splitting assembly is configured to split the light passing through the light splitting assembly into two coherent lights and then combine the two coherent lights. The first photodetector is configured to receive the light emitted by the first light source and reflected by the fundus and cornea of the eyeball. The processor is connected to the first photodetector. The processor is configured to obtain the axial length of the eyeball based on the electrical signal of the first photodetector. The refractive correction assembly is configured to compensate for the objective refractive error of the eyeball. The optometry device and the optometry method provided by the application improve the signal-to-noise ratio of the short coherent interference signal received by the first photodetector, so that the axial measurement result is more stable and accurate.

Description

Technical Field

[0001] This application relates to the field of medical device technology, specifically to optometry devices and optometry methods. Background Technology

[0002] Refractive errors have become a global public health problem. Studies predict that by 2050, the number of people with myopia worldwide will reach 4.758 billion (49.8% of the world's total population), and the number of people with high myopia will reach 938 million (9.8% of the world's total population). High myopia can lead to serious complications such as cataracts, retinal detachment, macular holes, and glaucoma, and in severe cases, it can even cause blindness, which is irreversible.

[0003] Refractive error screening is the foundation of myopia prevention and control. During refractive error screening, it is sometimes necessary to measure the axial length of the eye to differentiate between axial and non-axial myopia.

[0004] Axial length can be measured based on the principle of optical interference. This measurement relies on the interference of light reflected from the cornea and retina. However, when measuring axial length in eyes with refractive errors using optical interference, the results are often unstable or even impossible to measure. Summary of the Invention

[0005] The inventors of this application discovered that corneal reflected light is divergent and does not vary much from person to person, while retinal reflected light may be divergent (hyperopia), parallel (emmetropia), or convergent (myopia) depending on the refractive state of the eye. Moreover, the degree of convergence or divergence increases with the increase of refractive power, making it impossible to superimpose the corneal and retinal reflected light spots of eyes with different refractive powers using fixed focusing optical devices. This results in unstable or even unmeasurable axial length measurement results.

[0006] To at least partially solve the above problems, according to one aspect of this application, an embodiment of this application provides an optometry device. The optometry device includes a first light source, a beam splitter, a first photodetector, a processor, and a refractive correction component. The first light source is used to emit light to the eyeball of a subject. The beam splitter is disposed in the optical path from the first light source to the eyeball and is configured to split the light passing through the beam splitter into two coherent beams and then merge them. The optical path of one coherent beam is fixed, and the optical path of the other coherent beam is adjustable. The first photodetector is configured to receive light emitted by the first light source and reflected by the fundus and cornea of ​​the eyeball. The first photodetector is capable of converting the received light into a corresponding electrical signal. The processor is connected to the first photodetector and is configured to obtain the axial length of the eyeball based at least on the electrical signal from the first photodetector. The refractive correction component is configured to compensate for the objective refractive error of the eyeball. The light emitted by the first light source reaches the eyeball after passing through the beam splitter and the refractive correction component, and after being reflected by the fundus and cornea of ​​the eyeball, it reaches the first photodetector through the refractive correction component.

[0007] In some embodiments, the optometry device further includes a focusing lens assembly disposed in the optical path between the refractive correction component and the first photodetector. Light reflected from the fundus and cornea of ​​the eyeball is focused by the focusing lens assembly and then received by the first photodetector.

[0008] In some embodiments, the focusing lens assembly includes a first focusing lens and a second focusing lens. Light reflected from the fundus and cornea of ​​the eye is focused by the first focusing lens and the second focusing lens and then received by a first photodetector. The first focusing lens focuses the light reflected from the fundus and cornea of ​​the eye. The middle part of the second focusing lens is a light-transmitting part without focusing capability, and the part of the second focusing lens located at the circumferential edge of the light-transmitting part is a light-concentrating part with focusing capability, so that the focused light spots of the light reflected from the fundus and cornea of ​​the eye respectively on the first photodetector coincide.

[0009] In some embodiments, the light-transmitting portion is a through-hole structure or a planar lens structure.

[0010] In some embodiments, the optometry device further includes a polarizer, a polarizing beam splitter, and a quarter-wave plate. The polarizer is disposed in the optical path between the beam splitter and the refractive correction component, and is used to convert the light emitted from the beam splitter into S-polarized light. The polarizing beam splitter is disposed in the optical path between the polarizer and the refractive correction component, and is also located in the optical path between the first photodetector and the refractive correction component. The polarizing beam splitter can reflect S-polarized light and transmit P-polarized light. The quarter-wave plate is disposed in the optical path between the polarizing beam splitter and the refractive correction component. The light emitted from the first light source passes sequentially through the beam splitter and the polarizer to the polarizing beam splitter. After being reflected by the polarizing beam splitter, it passes sequentially through the quarter-wave plate and the refractive correction component to reach the eyeball. The light reflected from the fundus and cornea of ​​the eyeball passes sequentially through the refractive correction component and the quarter-wave plate to reach the polarizing beam splitter. After being transmitted by the polarizing beam splitter, it reaches the first photodetector.

[0011] In some embodiments, the optometry device further includes a first beam splitter, a wavefront sensor, a first relay telescope, and an analyzer. The first beam splitter is disposed in the optical path between the polarizing beam splitter and the refractive correction component. The first beam splitter is also disposed in the optical path between the polarizing beam splitter and the wavefront sensor. The wavefront sensor is capable of converting received light into corresponding electrical signals. The wavefront sensor is connected to a processor, which is further configured to obtain the objective refractive error of the eyeball based at least on the electrical signals from the wavefront sensor. The first relay telescope is disposed in the optical path between the first beam splitter and the wavefront sensor. The analyzer is disposed in the optical path between the first beam splitter and the first relay telescope. The polarization states of the analyzer and the polarizer are orthogonal to each other. The light emitted from the first light source is converted into S-polarized light by the polarizer, and then reflected by the polarizing beam splitter to the first beam splitter. After being reflected by the first beam splitter, the light passes through the refractive correction component and reaches the fundus of the eye. The light reflected from the fundus passes through the refractive correction component, is transmitted through the first beam splitter, and then passes through the analyzer and the first relay telescope in sequence to reach the wavefront sensor. The quarter-wave plate is detachably set in the optical path between the polarizing beam splitter and the refractive correction component. When the objective refractive data of the eye is obtained by the wavefront sensor, the quarter-wave plate is removed from the optical path between the polarizing beam splitter and the refractive correction component.

[0012] In some embodiments, a filter aperture is provided at the focal point in the middle of the first relay telescope.

[0013] In some embodiments, the optometry device further includes a second beam splitter, a target display device, and a target imaging objective. The second beam splitter is disposed in the optical path between the refractive correction component and the analyzer. Light reflected from the fundus of the eye can pass through the second beam splitter to reach the wavefront sensor. The target image displayed by the target display device can be reflected by the second beam splitter and then projected onto the eye through the refractive correction component. The target image displayed by the target display device can pass through the target imaging objective and be projected onto the second beam splitter.

[0014] In some embodiments, the optometry device further includes a third beam splitter, a second light source, a fourth beam splitter, a second photodetector, and a third focusing lens. Light emitted from the first light source reaches the beam splitting assembly via the third beam splitter; light emitted from the second light source reaches the beam splitting assembly via the third beam splitter, and the coherence length of the light emitted from the second light source is greater than the coherence length of the light emitted from the first light source; the fourth beam splitter is disposed in the optical path between the beam splitting assembly and the refractive correction assembly, and the fourth beam splitter is configured to transmit light from the first light source and reflect light from the second light source; the second photodetector is capable of receiving light from the second light source reflected by the fourth beam splitter, and the second photodetector is connected to a processor, and the second photodetector is capable of converting the received light into a corresponding electrical signal; the processor is further configured to obtain the axial length of the eyeball based on the electrical signals from the first and second photodetectors; the third focusing lens is disposed in the optical path between the fourth beam splitter and the second photodetector, and is used to focus the light from the second light source reflected by the fourth beam splitter.

[0015] In some embodiments, the first light source is a near-infrared broadband light source, and the second light source is a visible narrowband laser light source.

[0016] In some embodiments, a first collimating objective lens is further disposed in the optical path between the first light source and the third beam splitter, and a second collimating objective lens is further disposed in the optical path between the second light source and the third beam splitter.

[0017] In some embodiments, the beam splitting assembly includes a fifth beam splitter, a fixed right-angle reflecting prism, and a scanning right-angle reflecting prism. The distance between the scanning right-angle reflecting prism and the fifth beam splitter is adjustable. The light reaching the fifth beam splitter is transmitted and reflected by the fifth beam splitter into two beams. One beam is reflected from one side of the fifth beam splitter back to a first position by the fixed right-angle reflecting prism, and the other beam is reflected from the other side of the fifth beam splitter back to the first position by the scanning right-angle reflecting prism. After being transmitted and reflected by the fifth beam splitter at the first position, the two beams are merged into a single beam and emitted.

[0018] In some embodiments, the refractive correction component includes a defocus compensation component and an astigmatism compensation component, wherein the defocus compensation component is used to compensate for defocus of the eyeball, and the astigmatism compensation component is used to compensate for astigmatism of the eyeball.

[0019] In some embodiments, the defocus compensation component includes a second relay telescope.

[0020] In some embodiments, the astigmatism compensation component includes a pair of cylindrical lenses.

[0021] According to another aspect of this application, embodiments of this application also provide an optometry method, which is performed by an optometry device as provided in any embodiment of this application. The optometry method includes: acquiring the objective refractive error of the subject's eyeball; compensating for the objective refractive error of the eyeball by means of a refractive correction component based on the objective refractive error; forming two coherent beams from light emitted by a first light source using a beam splitter, and ensuring that the coherent beams pass through the refractive correction component to reach the cornea and fundus of the eyeball, wherein the optical path of one coherent beam is fixed and the optical path of the other coherent beam is adjustable; adjusting the optical path of the coherent beam with adjustable optical path, and receiving the light reflected from the cornea and fundus of the eyeball and passing through the refractive correction component by a first photodetector to obtain an interference result; and acquiring the axial length of the eyeball based at least on the interference result.

[0022] The optometry device and method provided in the embodiments of this application, when measuring axial length based on the principle of optical interference, correct the refractive error of the human eye through a refractive correction component before obtaining the axial length data. This eliminates the variation of the convergence and divergence of retinal reflected light with refractive power, increases the overlap of the focused light spot of retinal reflected light and corneal reflected light on the first photodetector, and improves the signal-to-noise ratio of the short coherent interference signal received by the first photodetector, making the axial length measurement results more stable and accurate. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, 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 this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the optometry device provided in an embodiment of this application;

[0025] Figure 2 This is a schematic diagram of the structure of the focusing lens assembly provided in the embodiments of this application, wherein the left figure is a side view of the first focusing lens and the second focusing lens, and the right figure is a front view of the second focusing lens;

[0026] Figure 3This is a schematic diagram of the focusing lens assembly provided in the embodiments of this application focusing corneal reflected light and retinal reflected light from the fundus, wherein the blue line indicates corneal reflected light and the green line indicates retinal reflected light from the fundus;

[0027] Figure 4 This is a schematic diagram of the principle of long coherent interferometric ranging provided in an embodiment of this application.

[0028] The attached figures are labeled as follows:

[0029] 1. Eyeball; 2. Second relay telescope; 3. Cylindrical mirror pair; 4. First beam splitter; 5. Second beam splitter; 6. Polarizer; 7. First relay telescope; 8. Filter aperture; 9. Wavefront sensor; 10. Mirror; 11. Target imaging objective; 12. Target display device; 13. Quarter-wave plate; 14. Polarizing beam splitter prism; 15. Focusing lens assembly; 16. First photodetector; 17. Fourth beam splitter; 18. Third focusing lens; 19. Second photodetector; 20. Polarizer; 21. Fixed right-angle reflecting prism; 22. Fifth beam splitter; 23. Third beam splitter; 24. First collimating objective; 25. First light source; 26. Second collimating objective; 27. Second light source; 28. Scanning right-angle reflecting prism.

[0030] It should be understood that the dimensions of the various parts shown in the accompanying drawings are not drawn to actual scale. Furthermore, the same or similar reference numerals denote the same or similar components. Detailed Implementation

[0031] The preferred embodiments of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection claimed in this application.

[0032] The terms "first," "second," and similar words used in this application do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. Words such as "including" or "contains" mean that the element preceding the word encompasses the element listed after it, and do not exclude the possibility of encompassing other elements as well. Terms such as "above," "below," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, this relative positional relationship may also change accordingly.

[0033] According to one aspect of this application, embodiments of this application provide an optometry device. Figure 1 This is a schematic diagram of the optometry device provided in the embodiments of this application, as shown below. Figure 1As shown, the optometry device includes a first light source 25, a beam splitter, a first photodetector 16, a processor, and a refractive correction component.

[0034] The first light source 25 is used to emit light into the eyeball 1 of the subject. For example, the first light source 25 can be a near-infrared broadband light source, which has a shorter coherence length, beneficial for measuring axial length. The light emitted by the first light source 25 can reach the eyeball 1 of the subject through the optical path structure of the optometry device.

[0035] A beam splitter is positioned in the optical path from the first light source 25 to the eyeball 1. The beam splitter is configured to split the light passing through it into two coherent beams, which are then combined. One coherent beam has a fixed optical path, while the other has an adjustable optical path. The beam splitter splits the light from the first light source 25 into two coherent beams and combines them, ensuring that both beams reach the subject's eyeball 1 along the same optical path. By adjusting the optical path of one coherent beam, interference occurs between the two beams after reflection from the eyeball 1. The interference result can be detected by the first photodetector 16. Here, the optical path refers to the distance the light emitted from the first light source 25 travels from the eyeball 1 to the first photodetector 16 after reflection.

[0036] A first photodetector 16 is configured to receive light emitted from a first light source 25 and reflected by the fundus and cornea of ​​the eyeball 1. The first photodetector 16 is capable of converting the received light into a corresponding electrical signal. Exemplarily, the first photodetector 16 can be one of a photodiode, a photomultiplier tube, or an avalanche photodiode. The first photodetector 16 is used to detect the interference result of two coherent beams emitted from the first light source 25 and convert the interference result into a corresponding electrical signal. A processor is connected to the first photodetector 16 and is configured to obtain the axial length of the eyeball 1 based at least on the electrical signal from the first photodetector 16. Exemplarily, the processor can obtain the axial length based on the electrical signal from the first photodetector 16 and the optical path adjustment amount of the beam splitter; the axial length can also be obtained through other methods described below.

[0037] The refractive correction component is configured to compensate for the objective refractive error of the eyeball 1. Light emitted from the first light source 25 reaches the eyeball 1 after passing through a beam splitter and the refractive correction component. After reflection from the fundus and cornea of ​​the eyeball 1, it reaches the first photodetector 16 via the refractive correction component. This configuration ensures that during axial length measurement, the coherent light reflected from the retina is protected by the refractive correction component to eliminate the influence of the eyeball 1's optical system refractive power before being received by the first photodetector 16. The objective refractive error can be obtained through the optometry devices provided in other embodiments of this application, or through other means or devices; this application does not limit this method.

[0038] The optometry device and method provided in the embodiments of this application, when measuring axial length based on the principle of optical interference, have a very small impact on the convergence and divergence of corneal reflected light due to the fact that the refractive power of the human eye (rarely exceeding 15D) is much smaller than the optical power of corneal reflected light (~256D). To a certain extent, this impact can be ignored. After correcting the refractive error of the human eye with the refractive correction component, the data on the axial length is obtained. This eliminates the change in the convergence and divergence of retinal reflected light with the refractive power, increases the overlap of the focused light spot of retinal reflected light and corneal reflected light on the first photodetector 16, and improves the signal-to-noise ratio of the short coherent interference signal received by the first photodetector 16, making the axial length measurement results more stable and accurate.

[0039] In some embodiments, the optometry device further includes a focusing lens assembly 15, which is disposed in the optical path between the refractive correction component and the first photodetector 16. Light reflected from the fundus and cornea of ​​the eyeball 1 is focused by the focusing lens assembly 15 and then received by the first photodetector 16. The focusing lens assembly 15 can focus the light reflected from the fundus and cornea of ​​the eyeball 1 so that the light spots on the first photodetector 16 coincide and match the target surface size of the first photodetector 16, so as to be better detected by the first photodetector 16.

[0040] Combination Figure 2 and Figure 3In some embodiments, the focusing lens assembly 15 includes a first focusing lens and a second focusing lens. Light reflected from the fundus and cornea of ​​the eyeball 1 is focused by the first focusing lens and the second focusing lens and then received by the first photodetector 16. The first focusing lens focuses the light reflected from the fundus and cornea of ​​the eyeball 1. The middle part of the second focusing lens is a light-transmitting part without focusing capability, and the part of the second focusing lens located at the circumferential edge of the light-transmitting part is a light-concentrating part with focusing capability, so that the focused light spots of the light reflected from the fundus and cornea of ​​the eyeball 1 coincide on the first photodetector 16. In this embodiment, after the light reflected from the retina and the light reflected from the cornea pass through the refractive correction component, the retinal reflected light (green line) is parallel light, and its focusing state on the first photodetector 16 does not change with the refractive state. However, the corneal reflected light (blue line) has a large divergence angle (approximately 256D optical power), and the effect of the refractive correction component on the convergence and divergence of the corneal reflected light is very small and can be ignored to a certain extent. As a result, the corneal reflected light and the retinal reflected light require different focusing degrees when they converge on the first photodetector 16. If a focusing lens with a single focusing power is used, the overlap of the focused light spots of the corneal reflected light and the retinal reflected light on the first photodetector 16 will be low. Therefore, in this embodiment, corneal and retinal reflected light are focused by combining a first focusing lens and a second focusing lens. The second focusing lens has a non-focusing, transparent portion in its center, while its peripheral edge forms a focusing portion. This ensures that the center of the second focusing lens does not focus retinal reflected light, while the edge focuses corneal reflected light. In other words, corneal reflected light can be focused by both the first and second focusing lenses, while retinal reflected light is focused only by the first focusing lens. This satisfies the different focusing requirements of corneal and retinal reflected light, maximizing the overlap of the focused spots on the first photodetector 16, improving the signal-to-noise ratio of the first photodetector 16, and thus improving the accuracy of axial length measurement. It also allows for better matching of the focused spots of corneal and retinal reflected light with the target surface size of the first photodetector 16. The first focusing lens can be a separate or cemented focusing lens, and the second focusing lens can be a flat-top focusing lens. In some embodiments, the transparent portion can be a through-hole structure or a planar lens structure.

[0041] Please continue reading. Figure 1In some embodiments, the optometry device further includes a polarizer 20, a polarizing beam splitter 14, and a quarter-wave plate 13. The polarizer 20 is disposed in the optical path between the beam splitter and the refractive correction assembly, and is used to convert the light emitted from the beam splitter into S-polarized light. The polarizing beam splitter 14 is disposed in the optical path between the polarizer 20 and the refractive correction assembly, and is also located in the optical path between the first photodetector 16 and the refractive correction assembly. The polarizing beam splitter 14 can reflect S-polarized light and transmit P-polarized light. The quarter-wave plate... 13 is disposed in the optical path between the polarizing beam splitter 14 and the refractive correction component; wherein, the light emitted by the first light source 25 passes through the beam splitter component and the polarizer 20 in sequence to reach the polarizing beam splitter 14, and after being reflected by the polarizing beam splitter 14, it passes through the quarter-wave plate 13 and the refractive correction component in sequence to reach the eyeball 1, and the light reflected by the fundus and cornea of ​​the eyeball 1 passes through the refractive correction component and the quarter-wave plate 13 in sequence to reach the polarizing beam splitter 14, and after being transmitted by the polarizing beam splitter 14, it reaches the first photodetector 16. The polarizing beam splitter 14 can be a polarizing cubic beam splitter prism. In this embodiment, the light passing through the polarizer 20 is converted into S-polarized light, and then the S-polarized light is converted into circularly polarized light by the quarter-wave plate 13. After the circularly polarized light is reflected by the eyeball 1, it is converted into P-polarized light by the quarter-wave plate 13, so that it can completely pass through the polarizing beam splitter 14, thereby improving the light energy utilization rate of the light reflected from the fundus and cornea, and thus improving the intensity of the light received by the first photodetector 16.

[0042] In some embodiments, the optometry device further includes a first beam splitter 4, a wavefront sensor 9, a first relay telescope 7, and an analyzer 6. The first beam splitter 4 is disposed in the optical path between the polarizing beam splitter 14 and the refractive correction component. The first beam splitter 4 is also disposed in the optical path between the polarizing beam splitter 14 and the wavefront sensor 9. The wavefront sensor 9 is capable of converting received light into corresponding electrical signals. The wavefront sensor 9 is connected to a processor, which is further configured to obtain the objective refractive error of the eyeball 1 based at least on the electrical signals from the wavefront sensor 9. The first relay telescope 7 is disposed in the optical path between the first beam splitter 4 and the wavefront sensor 9. The analyzer 6 is disposed in the optical path between the first beam splitter 4 and the first relay telescope 7, and performs polarization analysis. The polarization states of the polarizer 6 and the polarizer 20 are orthogonal to each other. The light emitted by the first light source 25 is converted into S-polarized light by the polarizer 20 and then reflected by the polarizing beam splitter 14 to the first beam splitter 4. After being reflected by the first beam splitter 4, the light passes through the refractive correction component and reaches the fundus of the eyeball 1. The light reflected from the fundus passes through the refractive correction component, is transmitted through the first beam splitter 4, and then passes through the analyzer 6 and the first relay telescope 7 in sequence to reach the wavefront sensor 9. The quarter-wave plate 13 is detachably disposed in the optical path between the polarizing beam splitter 14 and the refractive correction component. When the objective refractive data of the eyeball 1 is obtained by the wavefront sensor 9, the quarter-wave plate 13 is removed from the optical path between the polarizing beam splitter 14 and the refractive correction component.

[0043] In this embodiment, the first beam splitter 4, the first relay telescope 7, the wavefront sensor 9, and the analyzer 6 can share the first light source 25 in the axial length measurement optical path to achieve the objective refractive measurement function. The first beam splitter 4 can connect the axial length measurement optical path and the objective refractive measurement optical path. By setting the analyzer 6, polarized light reflected from optical devices in the optical path structure (such as the second relay telescope 2 and cylindrical lens pair 3 in the refractive correction assembly) and the cornea to the wavefront sensor 9 can be filtered to reduce measurement error. The light reflected from the fundus becomes unpolarized light, and the light whose polarization state is consistent with that of the analyzer 6 can pass through the analyzer 6 to reach the wavefront sensor 9 to obtain the objective refractive error of the eyeball 1. Objective refractive measurements can be achieved through techniques such as wavefront measurement, retinoscopy, strip grating focusing, Scheiner disc refraction, and blade measurement refraction. The wavefront sensor 9 can be one of the following: a Hartmann wavefront sensor based on a microlens array, a Hartmann wavefront sensor based on a microprism array, a curvature wavefront sensor, or a cone wavefront sensor.

[0044] In some embodiments, a filter aperture 8 is provided at the focal point in the middle of the first relay telescope 7, and the filter aperture 8 can further filter out off-axis stray light in the optical path.

[0045] In some embodiments, the optometry device further includes a second beam splitter 5, a target display device 12, and a target imaging objective lens 11. The second beam splitter 5 is disposed in the optical path between the refractive correction component and the analyzer 6. Light reflected from the fundus of the eyeball 1 can pass through the second beam splitter 5 to reach the wavefront sensor 9. The target image displayed by the target display device 12 can be reflected by the second beam splitter 5 and then projected onto the eyeball 1 through the refractive correction component. The target image displayed by the target display device 12 can pass through the target imaging objective lens 11 and be projected onto the second beam splitter 5. In this embodiment, the second beam splitter 5, the target display device 12, and the target imaging objective lens 11 form a subjective optometry optical path, which can be used to perform uncorrected and corrected visual acuity tests. The second beam splitter 5 can connect the subjective optometry optical path and the objective refractive measurement optical path. Exemplarily, the target display device 12 can be one of a CRT display, a commercial projector, a liquid crystal display, a plasma display, an electroluminescent display, or an organic light-emitting display. A reflector 10 can also be provided in the optical path between the imaging objective lens 11 and the second beam splitter 5. The reflector 10 can change the direction of light propagation, which is beneficial to controlling the size of the optometry device.

[0046] In some embodiments, the optometry device further includes a third beam splitter 23, a second light source 27, a fourth beam splitter 17, a second photodetector 19, and a third focusing lens 18. Light emitted from the first light source 25 reaches the beam splitting assembly via the third beam splitter 23; light emitted from the second light source 27 reaches the beam splitting assembly via the third beam splitter 23, and the coherence length of the light emitted from the second light source 27 is greater than the coherence length of the light emitted from the first light source 25; the fourth beam splitter 17 is disposed in the optical path between the beam splitting assembly and the refractive correction assembly, and the fourth beam splitter 17 is configured to transmit light from the first light source 25 and reflect light from it. The light source 27 receives light from the second light source 27 reflected by the fourth beam splitter 17. The second photodetector 19 is connected to a processor and converts the received light into a corresponding electrical signal. The processor is also configured to obtain the axial length of the eyeball 1 based on the electrical signals from the first photodetector 16 and the second photodetector 19. A third focusing lens 18 is positioned in the optical path between the fourth beam splitter 17 and the second photodetector 19 to focus the light from the second light source 27 reflected by the fourth beam splitter 17. The second light source 27 has a long coherence length and good coherence, enabling long-coherence ranging. The third beam splitter 23 can be a cubic beam splitter prism. In some embodiments, the second light source 27 is a visible narrowband laser source.

[0047] In this embodiment, the second light source 27, the fourth beam splitter 17, the second photodetector 19, and the third focusing lens 18 form a ranging optical path; the third beam splitter 23 is used to connect the second light source 27 into the optical path and can share the beam splitting component, polarizer 20, and other optical path structures with the first light source 25; the fourth beam splitter 17 is used to extract the light from the second light source 27 so that it can reach the second photodetector 19. The processor can simultaneously obtain the electrical signals from the first photodetector 16 and the second photodetector 19, and obtain the axial length more accurately based on the electrical signals from the first photodetector 16 and the second photodetector 19. Specifically, during axial length measurement, the light from the first light source 25 and the second light source 27 passes through the beam splitter along the same path. The beam splitter is adjusted to change the optical path of one path of coherent light with adjustable optical path. The optical path of the path of coherent light split by the first light source 25 and the second light source 27 is simultaneously adjusted. The electrical signals from the first photodetector 16 and the second photodetector 19 are collected, processed, and the axial length is obtained. Figure 4 The processing procedure is as follows: First, determine the center of the short coherence interference peak between the cornea and retina on the first photodetector 16. Figure 4 The distance D between the two vertical lines in the above figure is determined by measuring the long coherent sinusoidal interference signal on the second photodetector 19 between the interference peaks. Figure 4 The phase difference (shown in the figure below) is obtained using the formula: D = λN / (2n), where λ is the wavelength of the visible narrowband laser, N is the number of complete long-coherent sinusoidal interference signals between the interference peaks of the cornea and retina, and n is the refractive index of air at wavelength λ. Next, the axial length AL is calculated using the formula: AL = D / n eye , where n eye It is the average refractive index of the human eye at the center wavelength of a near-infrared broadband light source.

[0048] In some embodiments, a first collimating objective lens 24 is further disposed in the optical path between the first light source 25 and the third beam splitter 23, and a second collimating objective lens 26 is further disposed in the optical path between the second light source 27 and the third beam splitter 23. The first collimating objective lens 24 can be used to collimate the light emitted by the first light source 25, and the second collimating objective lens 26 can be used to collimate the light emitted by the second light source 27.

[0049] Combination Figure 1In some embodiments, the beam splitting assembly includes a fifth beam splitter 22, a fixed right-angle reflecting prism 21, and a scanning right-angle reflecting prism 28. The distance between the scanning right-angle reflecting prism 28 and the fifth beam splitter 22 is adjustable. Light reaching the fifth beam splitter 22 is transmitted and reflected by the fifth beam splitter 22 into two paths. One path is reflected back to a first position of the fifth beam splitter 22 from one side by the fixed right-angle reflecting prism 21, and the other path is reflected back to the first position of the fifth beam splitter 22 from the other side by the scanning right-angle reflecting prism 28. After being transmitted and reflected by the fifth beam splitter 22 at the first position, the two paths merge into a single beam. The fifth beam splitter 22 can be a cubic beam splitter prism. In this embodiment, the optical path length of the light passing through the scanning right-angle reflecting prism 28 is adjusted by changing the distance between the scanning right-angle reflecting prism 28 and the fifth beam splitter 22. In this embodiment, the light passing through the polarizing cubic beam splitter is focused onto the first photodetector 16 after passing through the focusing lens assembly 15. By moving the scanning right-angle reflecting prism 28, interference occurs between the corneal reflected light and the retinal reflected light at the fundus if and only if the optical path difference is less than the coherence length of the first light source 25, and the output signal of the first photodetector 16 reaches a maximum value. At the same time, the second light source 27 is turned on, and the light emitted from it is collimated by the second collimating objective lens 26, passes through the third beam splitter 23, and is split into two beams by the fifth beam splitter 22. The reflected light enters the scanning right-angle reflecting prism 28, and the transmitted light enters the fixed right-angle reflecting prism 21. After two reflections, it exits in a direction parallel to the incident light, is combined into one beam by the fifth beam splitter 22, passes through the polarizer 20, is reflected by the fourth beam splitter 17, and is focused onto the second photodetector 19 by the third focusing lens 18. By moving the scanning right-angle reflecting prism 28, the output signal of the second photodetector 19 reaches a maximum value for each wavelength of light emitted from the second light source 27 moved. The electrical signals of the first photodetector 16 and the second photodetector 19 are collected synchronously and transmitted to the processor for analysis and processing to obtain the axial length.

[0050] In some embodiments, the refractive correction component includes a defocus compensation component and an astigmatism compensation component, wherein the defocus compensation component is used to compensate for defocus of the eyeball 1, and the astigmatism compensation component is used to compensate for astigmatism of the eyeball 1.

[0051] In some embodiments, the defocus compensation component includes a second relay telescope 2. When refraction is performed on the eyeball 1, the pupil of the eyeball 1 is located on the focal plane of the first relay telescope 7 on the human eye side. The second relay telescope 2 may include two lenses, and defocus compensation is achieved by changing the distance between the two lenses. Defocus correction can be performed according to equation (1):

[0052] D=(d-f1-f2) / f1f2 (1)

[0053] Where D is the correctable defocus, f1 and f2 are the focal lengths of the two lenses in the second relay telescope 2, and d is the distance between the two lenses in the second relay telescope 2 along the optical axis. This is achieved by moving the entire telescope along the optical axis. Figure 1 The dashed box section modifies the distance between the two lenses on the optical axis in the second relay telescope 2, thereby achieving continuous correction of defocus on the eyeball 1.

[0054] In some embodiments, the astigmatism compensation component includes a pair of cylindrical lenses 3. When performing an eye exam on the eyeball 1, the pair of cylindrical lenses 3 can be positioned at the conjugate position of the pupil of the eyeball 1. Exemplarily, the pair of cylindrical lenses 3 can be a plano-concave / plano-convex cylindrical lens pair, a plano-concave / plano-concave cylindrical lens pair, or a plano-convex / plano-convex cylindrical lens pair with the same or different optical powers. By changing the rotation angle of the pair of cylindrical lenses 3, astigmatism compensation can be achieved. Astigmatism correction can be performed according to equation (2):

[0055] C = 2F c cos(a1-a2),φ=(a1+a2) / 2 (2)

[0056] Where C and φ are the correctable astigmatism magnitude and axis, respectively, and F c Let a1 and a2 be the astigmatism magnitude of a single cylindrical lens in cylindrical lens pair 3, and a1 and a2 be the astigmatism axes of the two cylindrical lenses in cylindrical lens pair 3. By rotating the single cylindrical lens in cylindrical lens pair 3 respectively, continuous correction of astigmatism of eyeball 1 can be achieved.

[0057] In some preferred embodiments, by combining the objective refractive measurement optical path, based on the objective measurement of the refractive error of the human eye, continuous and precise correction of the refractive error of the three eyes is achieved through optical internal focusing and rotating cylindrical lenses. This method does not require inserts and has high correction efficiency. After the refractive error of eyeball 1 is compensated, the axial length can be measured. In other words, the optometry device provided by the embodiments of this application integrates the objective refractive measurement optical path, the subjective optometry optical path, the refractive correction optical path, and the axial length measurement optical path. It simultaneously possesses the functions of objective measurement of human eye refractive error, assessment of uncorrected and corrected visual acuity, and measurement of axial length on a single device, acquiring eye health data in one go, significantly improving the efficiency of myopia screening, and providing a new means for rapid triage in ophthalmology clinics, improving triage efficiency and reducing medical costs.

[0058] Before and after refractive error compensation, uncorrected and corrected visual acuity tests are performed. Based on the test results, the following categories can be identified:

[0059] 1. If there is no refractive error and the uncorrected visual acuity is normal, then the human eye is normal;

[0060] 2. If there is no refractive error but the uncorrected visual acuity is abnormal, there may be other eye diseases, and other ophthalmological examinations (such as fundus photography) are needed to clarify the diagnosis.

[0061] 3. If there is refractive error but the corrected visual acuity is normal, then the human eye only has refractive error. Give the refractive measurement value.

[0062] 4. If there is refractive error and abnormal corrected visual acuity, the person's eye may have other eye diseases in addition to refractive error, and other ophthalmological examinations are needed to clarify the diagnosis.

[0063] Based on the axial length measurement results, simple refractive errors can be divided into the following two categories:

[0064] 1. If there is refractive error, but the corrected visual acuity is normal and the axial length is normal, then the human eye has non-axial refractive error;

[0065] 2. If there is refractive error, the corrected visual acuity is normal, but the axial length of the eye is abnormal, then the human eye has axial refractive error.

[0066] According to another aspect of this application, embodiments of this application also provide an optometry method, which is performed by an optometry device as provided in any embodiment of this application. The optometry method includes: acquiring the objective refractive error of the subject's eyeball 1; compensating for the objective refractive error of the eyeball 1 based on the objective refractive error using a refractive correction component; forming two coherent beams from the light emitted by the first light source 25 using a beam splitter, and ensuring that the coherent beams pass through the refractive correction component to reach the cornea and fundus of the eyeball 1, wherein the optical path of one coherent beam is fixed and the optical path of the other coherent beam is adjustable; adjusting the optical path of the coherent beam with adjustable optical path, and receiving the light reflected from the cornea and fundus of the eyeball 1 and passing through the refractive correction component through a first photodetector 16 to obtain an interference result; and acquiring the axial length of the eyeball 1 based at least on the interference result.

[0067] The optometry method provided in the embodiments of this application, when measuring axial length based on the principle of optical interference, corrects the refractive error of the human eye through a refractive correction component before obtaining the axial length data. This eliminates the variation of the convergence and divergence of retinal reflected light with refractive power, increases the overlap of the focused light spot of retinal reflected light and corneal reflected light on the first photodetector 16, and improves the signal-to-noise ratio of the short coherent interference signal received by the first photodetector 16, making the axial length measurement results more stable and accurate.

[0068] Based on the various embodiments of this application described above, in the absence of explicit denial or conflict, the technical features of one embodiment may be advantageously combined with one or more other embodiments.

[0069] While specific embodiments of this application have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of this application. Those skilled in the art should understand that modifications can be made to the above embodiments or equivalent substitutions can be made to some technical features without departing from the scope and spirit of this application.

Claims

1. An optometric device, characterized in that, include: A first light source, which is used to emit light into the eyes of the subject; A beam splitter is disposed in the optical path from the first light source to the eyeball. The beam splitter is configured to split the light passing through the beam splitter into two coherent beams and then merge them. The optical path of one coherent beam is fixed, while the optical path of the other coherent beam is adjustable. A first photodetector is configured to receive light emitted by the first light source and reflected by the fundus and cornea of ​​the eyeball, and the first photodetector is capable of converting the received light into a corresponding electrical signal. A processor connected to the first photodetector, the processor being configured to obtain the axial length of the eyeball based at least on the electrical signal from the first photodetector; A refractive correction component is configured to compensate for the objective refractive error of the eyeball, wherein light emitted from the first light source reaches the eyeball after passing through the beam splitting component and the refractive correction component, and after being reflected by the fundus and cornea of ​​the eyeball, reaches the first photodetector through the refractive correction component; The optometry device also includes a focusing lens assembly, which is disposed in the optical path between the refractive correction component and the first photodetector. The light reflected from the fundus and cornea of ​​the eyeball is focused by the focusing lens assembly and then received by the first photodetector. The focusing lens assembly includes a first focusing lens and a second focusing lens. The light reflected from the fundus and cornea of ​​the eyeball is focused by the first focusing lens and the second focusing lens and then received by the first photodetector. The first focusing lens focuses the light reflected from the fundus and cornea of ​​the eyeball. The middle part of the second focusing lens is a light-transmitting part without focusing capability, and the part of the second focusing lens located at the circumferential edge of the light-transmitting part is a light-concentrating part with focusing capability, so that the focused light spots of the light reflected from the fundus and cornea of ​​the eyeball respectively coincide on the first photodetector. The optometry device also includes: The third beam splitter is used to guide the light emitted from the first light source to the beam splitting assembly. The second light source emits light that passes through the third beam splitter to the beam splitting assembly. The coherence length of the light emitted by the second light source is greater than that of the light emitted by the first light source. A fourth beam splitter is disposed in the optical path between the beam splitting component and the refractive correction component. The fourth beam splitter is configured to transmit light from the first light source and reflect light from the second light source. The second photodetector is capable of receiving light from the second light source reflected by the fourth beam splitter. The second photodetector is connected to the processor and can convert the received light into a corresponding electrical signal. The processor is also configured to obtain the axial length of the eyeball based on the electrical signals from the first and second photodetectors.

2. The optometry device according to claim 1, characterized in that, The light-transmitting part is a through-hole structure or a planar lens structure.

3. The optometry device according to claim 1, characterized in that, Also includes: A polarizer is disposed in the optical path between the beam splitter and the refractive correction assembly, and is used to convert the light emitted from the beam splitter into S-polarized light. A polarizing beam splitter is disposed in the optical path between the polarizer and the refractive correction component, and is also located in the optical path between the first photodetector and the refractive correction component. The polarizing beam splitter can reflect S-polarized light and transmit P-polarized light. A quarter-wave plate is disposed in the optical path between the polarizing beam splitter and the refractive correction component; The light emitted from the first light source passes sequentially through the beam splitter and the polarizer to the polarizing beam splitter. After being reflected by the polarizing beam splitter, the light passes sequentially through the quarter-wave plate and the refractive correction component to the eyeball. The light reflected from the fundus and cornea of ​​the eyeball passes sequentially through the refractive correction component and the quarter-wave plate to the polarizing beam splitter. After being transmitted through the polarizing beam splitter, the light reaches the first photodetector.

4. The optometry device according to claim 3, characterized in that, Also includes: The first beam splitter is disposed in the optical path between the polarizing beam splitter and the refractive correction component; A wavefront sensor is provided, and the first beam splitter is also disposed in the optical path between the polarizing beam splitter and the wavefront sensor. The wavefront sensor can convert the received light into a corresponding electrical signal. The wavefront sensor is connected to the processor, and the processor is also configured to obtain the objective refractive error of the eyeball based at least on the electrical signal of the wavefront sensor. The first relay telescope is disposed in the optical path between the first beam splitter and the wavefront sensor; A polarizer is disposed in the optical path between the first beam splitter and the first relay telescope. The polarization states of the polarizer and the polarizer are orthogonal to each other. The light emitted from the first light source is converted into S-polarized light by the polarizer, and then reflected by the polarizing beam splitter to the first beam splitter. After being reflected by the first beam splitter, the light passes through the refractive correction component and reaches the fundus of the eye. The light reflected from the fundus passes through the refractive correction component, is transmitted through the first beam splitter, and then passes through the polarizer and the first relay telescope in sequence to reach the wavefront sensor. The quarter-wave plate is removably disposed in the optical path between the polarizing beam splitter and the refractive correction component. When the objective refractive data of the eyeball is obtained by the wavefront sensor, the quarter-wave plate is removed from the optical path between the polarizing beam splitter and the refractive correction component.

5. The optometry device according to claim 4, characterized in that, A filter aperture is provided at the focal point in the middle of the first relay telescope.

6. The optometry device according to claim 4, characterized in that, Also includes: The second beam splitter is disposed in the optical path between the refractive correction component and the analyzer, and the light reflected from the fundus of the eyeball can pass through the second beam splitter to reach the wavefront sensor; A visual target display device, wherein the visual target image displayed by the visual target display device can be reflected by the second beam splitter and then projected onto the eyeball through the refractive correction component; The target imaging objective lens allows the target image displayed by the target display device to be projected onto the second beam splitter through the target imaging objective lens.

7. The optometry device according to claim 1, characterized in that, Also includes: The third focusing lens is disposed in the optical path between the fourth beam splitter and the second photodetector, and is used to focus the light from the second light source reflected by the fourth beam splitter.

8. The optometry device according to claim 7, characterized in that, The first light source is a near-infrared broadband light source, and the second light source is a visible narrowband laser light source.

9. The optometry device according to claim 7, characterized in that, A first collimating objective lens is also provided in the optical path between the first light source and the third beam splitter, and a second collimating objective lens is also provided in the optical path between the second light source and the third beam splitter.

10. The optometry device according to claim 1, characterized in that, The beam splitting assembly includes a fifth beam splitter, a fixed right-angle reflecting prism, and a scanning right-angle reflecting prism, wherein the distance between the scanning right-angle reflecting prism and the fifth beam splitter is adjustable; The light rays reaching the fifth beam splitter are transmitted and reflected by the fifth beam splitter into two rays. One ray is reflected from one side of the fifth beam splitter back to the first position of the fifth beam splitter by the fixed right-angle reflecting prism, and the other ray is reflected from the other side of the fifth beam splitter back to the first position of the fifth beam splitter by the scanning right-angle reflecting prism. After being transmitted and reflected by the fifth beam splitter at the first position, the two rays are combined into a single ray and emitted.

11. The optometry device according to claim 1, characterized in that, The refractive correction component includes a defocus compensation component and an astigmatism compensation component. The defocus compensation component is used to compensate for defocus of the eyeball, and the astigmatism compensation component is used to compensate for astigmatism of the eyeball.

12. The optometry device according to claim 11, characterized in that, The defocus compensation component includes a second relay telescope.

13. The optometry device according to claim 11, characterized in that, The astigmatism compensation component includes a pair of cylindrical lenses.

14. A method for refraction, performed by the refraction apparatus as described in any one of claims 1-13, characterized in that, include: Obtain the objective refractive error of the subject's eyeball; Based on the objective refractive error, the objective refractive error of the eyeball is compensated by a refractive correction component; The light emitted from the first light source is split into two coherent beams using a beam splitter, and the coherent beams pass through the refractive correction assembly to reach the cornea and fundus of the eye. One coherent beam has a fixed optical path, while the other coherent beam has an adjustable optical path. The optical path of a coherent light with adjustable optical path is adjusted, and the light reflected from the cornea and fundus of the eyeball and passing through the refractive correction component is received by the first photodetector to obtain the interference result; Based at least on the interference results, the axial length of the eyeball is obtained.

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