Refraction type multi-focus artificial lens

Abstract

The invention discloses a refraction type multi-focus intraocular lens, and relates to the technical field of intraocular lenses. The refraction type multi-focus intraocular lens comprises a first lens and a second lens, the diopter of the second lens is larger than that of the first lens, a cornea and the first lens form a far focus, the cornea and the second lens form a near focus, the optical center of the first lens and the optical center of the second lens are located on the same optical axis, and the optical center of the second lens is located behind the optical center of the first lens. The distance between the near focus and the far focus is shortened; when a user sees a distance, light rays emitted by a long-distance object pass through the cornea and the second lens to be focused on the perifocus, continue to be spread in the direction of the far focus (retina) and reach the far focus to form an out-of-focus blurred image. Light emitted by a long-distance object is refracted by the cornea and the first lens to form a clear target image at the far focus; the distance between the perifocus and the far focus is shortened, and the optical interference of the out-of-focus blurred image on the far focus target image is less, so that the quality of the target image is improved.

Description

Technical Field

[0001] The invention relates to the technical field of artificial lenses, and in particular to a refractive multifocal artificial lens. Background Art

[0002] An intraocular lens (IOL) is an artificial lens that replaces the natural lens in the eye during cataract surgery. Traditional monofocal IOLs can only provide a single optical power, usually optimizing distance vision. However, because they only have one optical power, monofocal IOLs cannot provide clear vision for near and intermediate distances, causing patients after cataract removal to rely on additional corrective measures, such as frame glasses or corneal contact lenses, for these activities.

[0003] In order to achieve good distance vision and near vision at the same time, multifocal intraocular lenses came into being. Multifocal intraocular lenses can provide 2 to 3 focal points at the same time, allowing patients to obtain good vision at different distances (such as near, medium and long distances).

[0004] When studying the multifocal intraocular lenses currently on the market, the inventors found that they have the following technical defects: When looking at a distant object, the light emitted by the distant object is refracted by the cornea and the far vision optical zone and converges at the far focus (retina) to form a clear target image. At the same time, the light emitted by the distant object is refracted by the cornea and the near vision optical zone and converges at the near focus. The light continues to propagate toward the far focus (retina) and forms a defocused blurred image at the far focus (retina). Since the blurred image and the target image overlap at the far focus (retina), visual interference (such as ghosting) occurs, which reduces the image quality.

[0005] In summary, while existing multifocal intraocular lenses provide multiple focal points, it is difficult to avoid the overlap of out-of-focus blurred images on the clear target images at far focus, causing visual interference (such as ghosting), making it difficult to provide a more ideal visual effect. Summary of the invention

[0006] In order to solve the above technical problems, the purpose of the present invention is to provide a refractive multifocal intraocular lens, aiming to reduce the interference of the out-of-focus blurred image on the far-focus clear target image, thereby providing a more ideal visual effect.

[0007] The technical solution provided by the present invention is as follows: A refractive multifocal intraocular lens, comprising: The first lens forms a far vision optical zone, and the focus formed by the far vision optical zone and the cornea is a far focus; The second lens forms a near optical zone, and the focus formed by the near optical zone and the cornea is a near focus; The refractive power of the second lens is greater than that of the first lens, and the optical center of the second lens is located behind the optical center of the first lens, and the optical center of the first lens and the optical center of the second lens are on the same optical axis.

[0008] Furthermore, the first lens is a biconvex lens, the second lens is a plano-convex lens with a flat front surface and a convex rear surface, and the biconvex lens is arranged in a circumferential direction of the plano-convex lens.

[0009] Further, the plano-convex lens is located in the central area of ​​the biconvex lens, or the plano-convex lens is located in the para-central area of ​​the biconvex lens.

[0010] Furthermore, the plano-convex lens is located in the central area of ​​the biconvex lens, and the refractive power of the front convex surface of the biconvex lens is greater than the refractive power of the rear convex surface thereof.

[0011] Furthermore, the diopter of the front convex surface of the biconvex lens is 6D greater than the diopter of the back convex surface thereof.

[0012] Furthermore, the first lens is a first type biconvex lens, the second lens is a second type biconvex lens, and the refractive power of the rear convex surface of the second type biconvex lens is greater than the refractive power of the front convex surface thereof.

[0013] Furthermore, the first type of biconvex lens is arranged in a circumferential direction of the second type of biconvex lens, the second type of biconvex lens is located in a central area of ​​the first type of biconvex lens, the refractive power of the front convex surface of the first type of biconvex lens is greater than the refractive power of the rear convex surface, and the refractive power of the rear convex surface of the second type of biconvex lens is greater than the refractive power of the front convex surface.

[0014] Furthermore, the refractive power of the front convex surface of the first type of biconvex lens is 6D greater than the refractive power of the rear convex surface thereof, and the refractive power of the rear convex surface of the second type of biconvex lens is 6D greater than the refractive power of the front convex surface thereof.

[0015] Furthermore, the second type of biconvex lens is arranged in a circumferential direction of the first type of biconvex lens, the first type of biconvex lens is located in a central area of ​​the second type of biconvex lens, the refractive power of the front convex surface of the first type of biconvex lens is greater than the refractive power of the rear convex surface, and the refractive power of the rear convex surface of the second type of biconvex lens is greater than the refractive power of the front convex surface.

[0016] Furthermore, the first lens is a first type of plano-convex lens with a convex front surface and a flat rear surface, and the second lens is a second type of plano-convex lens with a flat front surface and a convex rear surface.

[0017] Compared with the prior art, the refractive multifocal intraocular lens provided by the embodiment of the present invention has at least the following technical effects: By arranging the refractive power of the second lens to be greater than that of the first lens and the optical center of the second lens to be located behind the optical center of the first lens, the distance between the near focus and the far focus is shortened, and the interference of the out-of-focus blurred image on the clear target image at the far focus is reduced, thereby providing a more ideal visual effect.

[0018] Specifically, when looking at a distant object, the light emitted by the distant object is refracted by the cornea and the far vision optical zone and converges at the far focus (retina) to form a clear target image. At the same time, the light emitted by the distant object is refracted by the cornea and the near vision optical zone and converges at the near focus. The light continues to propagate toward the far focus (retina) and forms a defocused blurred image at the far focus (retina). The closer the near focus is to the far focus, the less blurred the defocused blurred image is at the far focus (retina) and the smaller the range of the blurred image. Therefore, the interference with the clear target image at the far focus is smaller, and the visual interference generated is relatively small, resulting in higher imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 It is a front view of the refractive multifocal intraocular lens of the present invention; Figure 2 for Figure 1 Side view of Figure 3 is a side view of a refractive multifocal intraocular lens in a specific embodiment of the present invention; Figure 4 for Figure 3 The corresponding side view of the first lens (biconvex lens); Figure 5 for Figure 3 The corresponding side view of the second lens (plano-convex lens); Figure 6 for Figure 3 Corresponding optical imaging schematic diagram; Figure 7 is a front view of a refractive multifocal intraocular lens in a comparative embodiment; Figure 8 for Figure 7 Side view of Fig. 9 for Figure 7 The side view corresponding to the mid-γ optical zone; Fig.10 for Figure 7 Side view corresponding to the middle alpha optical zone; Fig.11 for Figure 7 Corresponding optical imaging schematic.

[0021] Reference numerals: 10. First lens; 101. Biconvex lens; 102. First optical center; 20. Second lens; 201. Plano-convex lens; 202. Second optical center; 30. γ optical zone; 301. Third optical center; 40. α optical zone; 401. Fourth optical center. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0023] It should be noted that when an element is referred to as being "fixed on" or "set on" another element, it can be directly on the other element or indirectly set on the other element; when an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0024] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0025] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, "multiple" and "several" mean two or more, unless otherwise clearly and specifically defined.

[0026] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the conditions under which this application can be implemented. Therefore, they have no substantive technical significance. Any structural modification, change in proportional relationship or adjustment of size should still fall within the scope of the technical content disclosed in this application without affecting the effects and purposes that can be achieved by this application.

[0027] The lens of the human eye is a biconvex lens that is flexible and can become thicker or thinner as needed to achieve focusing, ensuring that we can clearly see objects at different distances. Under normal circumstances, the lens can flexibly adjust its shape, allowing the eye to switch focus freely between looking far and near. However, when the lens gradually becomes cloudy, it will cause cataracts. Cataracts are a common eye disease in which the lens becomes opaque and affects vision. Cataract treatment usually requires phacoemulsification surgery to crush the cloudy lens into a fine paste and suck it out. After that, an artificial lens is implanted to replace the original natural lens and restore the patient's vision.

[0028] Specifically, an intraocular lens (IOL) is an artificial lens that replaces the natural lens in the eye during cataract surgery. Traditional monofocal IOLs can only provide a single optical power (unit: diopters, D), which usually optimizes distance vision (i.e., vision for distant objects). However, because it only has one optical power, monofocal IOLs cannot provide clear vision suitable for close distances (such as reading a book or newspaper at 40 cm) and medium distances (such as using a computer at 60-80 cm), resulting in patients may need to rely on additional corrective means such as frame glasses or corneal contact lenses for such activities.

[0029] In order to achieve good distance vision and near vision at the same time, multifocal intraocular lenses came into being. Multifocal intraocular lenses can provide 2 to 3 focal points at the same time, so that patients can have good vision at different distances (such as near, middle and far distances). Multifocal intraocular lenses that provide 2 focal points at the same time are bifocal intraocular lenses, and those that provide 3 focal points at the same time are trifocal intraocular lenses. Bifocal intraocular lenses: The light emitted by distant objects and near (40 cm) objects forms two focal points after passing through bifocal intraocular lenses, and can see distant objects and near objects. Trifocal intraocular lenses: The light emitted by distant objects, medium (60~80 cm) objects and near (40 cm) objects forms three focal points after passing through trifocal intraocular lenses, and can see distant objects, medium objects and near objects.

[0030] There are several types of multifocal intraocular lenses on the market: The Refractive Multifocal Intraocular Lens is an early multifocal intraocular lens that provides both distance and near vision. The design of this intraocular lens uses a concave and convex refractive ring to achieve multifocal vision. However, this design can cause some discomfort, especially glare. In addition, the requirements for the center position of the intraocular lens implanted in the eye are very high, and a slight deviation may lead to a decrease in visual quality.

[0031] The zone-refractive multifocal intraocular lens has two asymmetric refractive optical zones. The upper zone forms far vision, while the lower fan-shaped zone adds +3.0 D of refraction to form near vision. The overall structure achieves a good balance between far and near vision. This lens retains the advantages of refractive intraocular lenses, with less light energy loss and the ability to provide higher contrast sensitivity under different lighting conditions. However, this type of lens also has some disadvantages, including larger coma and trefoil aberration. In addition, due to its zone-separated design, image jumps may occur, affecting the visual experience.

[0032] Diffractive Multifocal Intraocular Lens can provide patients with both far and near vision. Among them, diffractive trifocal intraocular lenses can meet more comprehensive vision needs, covering far, intermediate and near vision. The design of this type of diffractive intraocular lens uses multiple uneven diffraction ring structures on its surface. Although this design can achieve multifocal vision, it also leads to relatively low light energy utilization and causes side effects such as glare and visual interference.

[0033] The refractive intraocular lens designed with EDOF (Extended Depth of Focus) adopts an innovative design without refractive rings and diffraction rings. It uses high-order aspheric technology to gradually and smoothly increase the refractive power of the optical zone of the intraocular lens from the periphery to the center. In this design, there is no obvious jump or zone separation on the front surface, ensuring the smooth transmission of light. For example, in the design of the Tecnis Eyhance ICB00 intraocular lens, the refractive power of the optical part increases continuously and gradually by about 0.5 D from the periphery to the center. The additional refractive power in the central 2 mm area can effectively increase spherical aberration, thereby extending the depth of field and improving intermediate vision. This design enables patients to obtain good distance vision and intermediate vision, but it is still not ideal in terms of near vision.

[0034] The wavefront reshaping EDOF intraocular lens uses X-WAVE™ technology and contains two smooth surface transition elements. Among them, surface transition element 1 is a slightly raised smooth flat top (height about 1 µm), which can effectively stretch the wavefront to form a continuous depth of field. Surface transition element 2 has a small curvature change (about 2.2 mm area) to move the wavefront to maximize the use of all available light energy, helping to move the continuously extended focal length in front of the retina for better distance and intermediate vision. However, for good near vision, glasses of at least +1.0 D are required.

[0035] In summary, the multifocal intraocular lenses currently on the market have their own advantages and disadvantages. Although they have made certain progress in providing multiple focal points and can provide far vision, intermediate vision and near vision, the visual interference is relatively obvious and it is still difficult to provide a more ideal visual effect.

[0036] When studying the multifocal intraocular lenses currently on the market, the inventors found that they have the following technical defects: When looking at a distant object, the light emitted by the distant object is refracted by the cornea and the far vision optical zone and converges at the far focus (retina) to form a clear target image; at the same time, the light emitted by the distant object is refracted by the cornea and the near vision optical zone and converges at the near focus. The light continues to propagate toward the far focus (retina) and forms a defocused blurred image at the far focus (retina). Because the blurred image and the target image overlap at the far focus (retina), visual interference (such as ghosting) occurs, which reduces the image quality.

[0037] In summary, while existing multifocal intraocular lenses provide multiple focal points, it is difficult to avoid the overlap of out-of-focus blurred images on the clear target images at far focus, causing visual interference (such as ghosting), making it difficult to provide a more ideal visual effect.

[0038] Please refer to the attached Figure 1 and attached Figure 2 As shown, an embodiment of the present invention provides a refractive multifocal intraocular lens, comprising a first lens 10 and a second lens 20. The first lens 10 forms a far vision optical zone, and the focus formed by the far vision optical zone and the cornea is a far focus; the second lens 20 forms a near vision optical zone, and the focus formed by the near vision optical zone and the cornea is a near focus; wherein the refractive power of the second lens 20 is greater than the refractive power of the first lens 10, and the optical center of the second lens 20 is located behind the optical center of the first lens 10, and the optical center of the first lens 10 and the optical center of the second lens 20 are on the same optical axis.

[0039] In this embodiment, the refractive power of the second lens 20 is greater than the refractive power of the first lens 10, the optical center of the first lens 10 and the optical center of the second lens 20 are on the same optical axis, and the optical center of the second lens 20 is located behind the optical center of the first lens 10, so that the near focus is moved back to the far focus, the distance between the near focus and the far focus is shortened, and the interference of the out-of-focus blurred image on the clear target image is reduced, thereby providing a more ideal visual effect.

[0040] Specifically, when looking at a distant object, the light emitted by the distant object is refracted by the cornea and the far vision optical zone and converges at the far focus (retina) to form a clear target image; at the same time, the light emitted by the distant object passes through the cornea and the near vision optical zone and converges at the near focus. The light continues to propagate toward the far focus (retina) and forms a defocused blurred image at the far focus (retina). The closer the near focus is to the far focus, the less blurred the defocused blurred image is at the far focus (retina) and the smaller the range of the blurred image. Therefore, the interference to the clear target image at the far focus is smaller, and the visual interference generated is relatively small, resulting in higher imaging quality.

[0041] It can be explained that the optical center refers to the point in the lens where light will not be refracted or deflected when passing through it. Diopter is a physical quantity that measures the focusing ability of a lens. It is defined as the reciprocal of the focal length of the lens (unit: meter). The larger the diopter, the stronger the focusing ability of the lens and the shorter the focal length.

[0042] In some optional embodiments, the first lens 10 is a biconvex lens, and the second lens 20 is a plano-convex lens with a flat front surface and a convex rear surface, and the biconvex lens ring is arranged in the circumference of the plano-convex lens. The optical center of the biconvex lens and the optical center of the plano-convex lens are on the same optical axis. The refractive power of the plano-convex lens is greater than that of the biconvex lens. It should be further explained that the refractive power of the plano-convex lens can be +3D greater than that of the biconvex lens. The connection between the biconvex lens and the plano-convex lens is a zero height difference transition, and there are no refraction rings and diffraction rings on the lens surface, which improves the imaging quality and light energy utilization, and reduces scattering and glare. In this embodiment, the light emitted by the distant object is refracted by the cornea and the biconvex lens in the far vision optical zone and is clearly imaged at the far focus, and the far focus is located on the retina; at the same time, the light emitted by the distant object is refracted by the cornea and the plano-convex lens in the near vision optical zone and converges at the near focus, and the light continues to propagate toward the far focus (retina) and forms a defocused blurred image at the far focus (retina); when the near focus is closer to the far focus, the defocused blurred image is less blurred at the far focus (retina) and the range of the blurred image is smaller, so the interference to the clear target image at the far focus is smaller, and the visual interference generated is relatively small, so that the imaging quality will be higher.

[0043] It can be explained that a biconvex lens is a lens with two convex surfaces (i.e. curved outwards) that is able to focus parallel light rays to a single focal point. The optical center of a thin biconvex lens with the same curvature on the front and back surfaces is located at its geometric center. A plano-convex lens consists of a flat surface and a convex surface. The optical center of a thin plano-convex lens is located at the very vertex of the convex surface.

[0044] In some optional embodiments, the plano-convex lens is located in the central area of ​​the biconvex lens, or the plano-convex lens is located in the paracentral area of ​​the biconvex lens. The central area is the central part of the intraocular lens, and the paracentral area is around the central area of ​​the intraocular lens, but still within the range of the central area.

[0045] In some optional embodiments, the optical center of the plano-convex lens is located at the top of the convex surface. The curvature radius of the front and rear surfaces of the biconvex lens is equal, and its optical center is located at the geometric center. The comprehensive refractive power of the plano-convex lens is greater than that of the biconvex lens. The plano-convex lens forms a near vision optical zone, and the focus formed together with the cornea is the near focus, which is used to see close objects, such as mobile phones and books and newspapers. The biconvex lens forms a far vision optical zone, and the focus formed together with the cornea is the far focus, which is used to see distant objects.

[0046] In some optional embodiments, the plano-convex lens is located in the central area of ​​the biconvex lens, and the refractive power of the front convex surface of the biconvex lens is greater than the refractive power of the back convex surface thereof.

[0047] In a specific embodiment, the diopter of the front convex surface of the biconvex lens is 6D greater than the diopter of the back convex surface thereof.

[0048] In some optional embodiments, the first lens 10 is a first type of biconvex lens, and the second lens 20 is a second type of biconvex lens, wherein the refractive power of the rear convex surface of the second type of biconvex lens is greater than the refractive power of the front convex surface thereof.

[0049] In some optional embodiments, the first type of biconvex lenses are arranged around the circumference of the second type of biconvex lenses, and the refractive power of the rear convex surface of the second type of biconvex lenses is greater than the refractive power of the front convex surface thereof.

[0050] In some optional embodiments, the second type of biconvex lens is located in the central area of ​​the first type of biconvex lens, the refractive power of the front convex surface of the first type of biconvex lens is greater than the refractive power of its back convex surface, and the refractive power of the back convex surface of the second type of biconvex lens is greater than the refractive power of its front convex surface.

[0051] In a specific embodiment, the refractive power of the front convex surface of the first type of biconvex lens is 6D greater than the refractive power of the back convex surface thereof. The refractive power of the back convex surface of the second type of biconvex lens is 6D greater than the refractive power of the front convex surface thereof.

[0052] In some optional embodiments, the second type of biconvex lens is arranged circumferentially around the first type of biconvex lens, the first type of biconvex lens is located in the central area of ​​the second type of biconvex lens, the refractive power of the front convex surface of the first type of biconvex lens is greater than the refractive power of its rear convex surface, and the refractive power of the rear convex surface of the second type of biconvex lens is greater than the refractive power of its front convex surface.

[0053] In a specific embodiment, the refractive power of the front convex surface of the first type of biconvex lens is 6D greater than the refractive power of the back convex surface thereof. The refractive power of the back convex surface of the second type of biconvex lens is 6D greater than the refractive power of the front convex surface thereof.

[0054] In some optional embodiments, the first lens 10 is a first type of plano-convex lens with a convex front surface and a flat rear surface, and the second lens 20 is a second type of plano-convex lens with a flat front surface and a convex rear surface. The first type of plano-convex lens is arranged around the circumference of the second type of plano-convex lens, and the second type of plano-convex lens is located in the central area of ​​the first type of plano-convex lens.

[0055] In order to further illustrate the technical effect of the refractive multifocal intraocular lens provided by the present invention, we compare the specific embodiment of the present invention with the comparative embodiment, as follows: In a specific embodiment of the present invention, please refer to the attached Figure 3 To Attachment Figure 5 As shown, the diameter of the refractive multifocal intraocular lens is 6 mm. Among them, the plano-convex lens 201 is located in the central area, and its diameter is ≤1.8 mm. The biconvex lens 101 is arranged around the circumference of the plano-convex lens 201, and its inner diameter is greater than 1.8 mm, and its outer diameter is ≤6 mm. It should be further explained that in the following embodiments, the φ area represents the far vision optical zone, and the β area represents the near vision optical zone.

[0056] Furthermore, the thickness of the refractive multifocal intraocular lens at its thickest point is 1.2 mm, the optical center of the biconvex lens 101 is the first optical center 102, and the first optical center 102 is located at its geometric center, and the optical center of the plano-convex lens 201 is the second optical center 202, and the second optical center 202 is located at the topmost point of the convex surface of its rear surface. Therefore, the second optical center 202 is moved backward by 0.6 mm compared to the first optical center 102, and this distance is equivalent to half of the thickness of the refractive multifocal intraocular lens at its thickest point.

[0057] The original theoretical calculation formula for the refractive power of artificial lenses is:

[0058] in, P 0 is the refractive power of the intraocular lens, n1 is the refractive index of the aqueous humor (1.337), n2 is the refractive index of the vitreous body (1.336), A Xis the axial length (i.e. the distance from the corneal vertex to the retina, in meters), d is the effective anterior chamber depth (in meters, in clinical applications, d is generally defined as the distance from the corneal vertex to the vertex of the anterior surface of the intraocular lens), and k is the curvature of the anterior surface of the cornea.

[0059] According to formula (1), the calculation formula of eye axis Ax is derived as follows:

[0060] For example: The curvature of the anterior surface of the right cornea of ​​a patient is 44.84D. After completing phacoemulsification to remove the cataract nucleus and cortex, in order to see distant objects clearly, an artificial lens with a refractive power of 22D needs to be implanted; and in order to see close objects clearly, the refractive power required is 25D.

[0061] First, calculate the eye axis A corresponding to the light emitted by the distant object after being refracted through the cornea and the φ-zone biconvex lens X1 Value: The curvature of the front surface of the cornea is 44.84D. The refractive power of the φ-zone biconvex lens is 22D, and the curvature radius of the front and back surfaces is equal. After the light passes through the cornea and the φ-zone biconvex lens, it forms a far focus (located on the retina) to see distant objects. According to the thin biconvex lens theory, the optical center of the φ-zone biconvex lens is located at the geometric center of the φ-zone biconvex lens. Figure 6 As shown in the figure, the two light rays aa1 and bb1 are refracted by the cornea and the φ-zone biconvex lens and focused at f0 on the optical axis, forming a far focus. According to formula (2), d is generally the distance from the corneal vertex to the vertex of the front surface of the intraocular lens, in meters (m). The distance from the corneal vertex to the vertex of the front surface of the intraocular lens of the patient's right eye is 0.00457m. Because the thickness of intraocular lenses is different, in order to increase the accuracy of the calculation results, we define d as the distance from the corneal vertex to the optical center of the intraocular lens. The distance from the vertex of the front surface of the intraocular lens to the optical center of the intraocular lens is equal to half of the thickness of the thickest part of the intraocular lens. If the thickness of the intraocular lens is 0.0012m, then the distance from the vertex of the front surface of the intraocular lens to the optical center is 0.0006m. Therefore, the distance from the corneal vertex to the optical center of the intraocular lens d = the distance from the corneal vertex to the vertex of the front surface of the intraocular lens (0.00457m) + the distance from the vertex of the front surface of the intraocular lens to the optical center of the intraocular lens (0.0006m) = 0.00457m + 0.0006m = 0.00517m. That is to say, the distance from the vertex of the anterior surface of the cornea to the optical center of the φ zone is 0.00517 m. According to formula (2), substituting the above data into the formula, the corresponding eye axis A of the light emitted by the distant object after being refracted through the cornea and the φ zone biconvex lens is calculated. X1 , and the result is A X1=0.022692m(22.692mm). That is to say, the focus of the image formed by the light emitted by the distant object after being refracted by the cornea and the φ-zone biconvex lens is located on the optical axis 22.692mm behind the vertex of the anterior surface of the cornea, that is, at f0 (retina) of the optical axis.

[0062] Then calculate the eye axis A corresponding to the same set of light rays after refraction through the cornea and the β-zone plano-convex lens X2 Value: The curvature of the front surface of the cornea is 44.84D. The β zone is a plano-convex lens, with a flat front surface and a convex back surface. The front surface refractive power is zero, and the back surface refractive power is 25D, forming a near focus f1. According to the thin plano-convex lens theory, the optical center of the β zone plano-convex lens is located at the top of the convex surface of its back surface. Figure 6 As shown, the two light rays cc1 and dd1 are refracted by the cornea and the β-zone plano-convex lens respectively and then focused at f1 on the optical axis. According to formula (2), d is generally the distance from the corneal vertex to the vertex of the front surface of the intraocular lens. The distance from the corneal vertex to the vertex of the front surface of the intraocular lens of the patient's right eye is 0.0457m. Because the thickness of intraocular lenses is different, in order to increase the accuracy of the calculation results, we define d as the distance from the corneal vertex to the optical center of the intraocular lens. The distance from the front surface of the intraocular lens to the optical center of the intraocular lens is equal to the thickness of the thickest part of the intraocular lens. If the thickness of the intraocular lens is 0.0012m, then the distance from the front surface of the intraocular lens to the optical center is 0.0012m. Therefore, the distance from the corneal vertex to the optical center of the intraocular lens d = the distance from the corneal vertex to the vertex of the front surface of the intraocular lens (0.00457m) + the distance from the front surface of the intraocular lens to the optical center of the intraocular lens (0.0012m) = 0.00457m + 0.0012m = 0.00577m. That is to say, the distance from the vertex of the anterior surface of the cornea to the optical center of the β zone is 0.00577 m. According to formula (2), substituting the above data, the eye axis AX2 corresponding to the refraction of the light emitted by the distant object through the cornea and the β zone plano-convex lens is calculated, and the result A is obtained. X2 =0.022346m(22.346mm). That is to say, the focus of the image formed by the light emitted by the distant object after being refracted by the cornea and the β-zone plano-convex lens is located on the optical axis 22.346mm behind the corneal vertex, that is, at f1 of the optical axis.

[0063] Calculate the distance Δ between the focus f0 and the focus f1 in this embodiment = A X1 -A X2 =22.692mm-22.346mm=0.346mm.

[0064] In a specific embodiment of the comparison, please refer to the attached Figure 7 To Attachment Fig.10As shown, the diameter of the intraocular lens in the comparative embodiment is 6mm. It is composed of an α optical zone 40 and a γ optical zone 30. The central area of ​​the α optical zone 40 with a diameter of ≤1.8mm is a biconvex lens, and the curvature radius of the front and rear surfaces are equal. The comprehensive refractive power of the α optical zone 40 is 3D greater than the comprehensive refractive power of the γ optical zone 30; the inner diameter of the γ optical zone 30 is greater than 1.8mm, and the outer diameter is ≤6mm, which is a biconvex lens, and the curvature radius of the front and rear surfaces are equal; the connection between the β optical zone and the φ optical zone is a zero height difference transition; the thickness of the thickest part of the intraocular lens is 0.0012m.

[0065] The γ optical zone 30 is a biconvex lens, and the curvature radius of the front and rear surfaces is equal, forming a far focus, which is used to view distant objects; according to the principle of thin biconvex lenses, the curvature radius of the front and rear surfaces is equal, and the optical center corresponding to the γ optical zone 30 is the third optical center 301, and the third optical center 301 is located at the geometric center of the γ optical zone 30. The α optical zone 40 is also a biconvex lens, and the comprehensive refractive power of the α optical zone 40 is 3D greater than the comprehensive refractive power of the γ optical zone 30. The α optical zone 40 forms a near focus, which is used to view close objects, such as mobile phones, books and newspapers. According to the principle of thin biconvex lenses, the optical center corresponding to the α optical zone 40 is the fourth optical center 401, and the fourth optical center 401 is located at the geometric center of the α optical zone 40. The third optical center 301 and the fourth optical center 401 overlap.

[0066] For example: For the same patient as in the previous case, the curvature of the anterior surface of the right cornea is 44.84D. After completing the phacoemulsification to remove the cataract nucleus and cortex, in order to see distant objects clearly, an artificial lens with a refractive power of 22D needs to be implanted, and in order to see close objects clearly, the refractive power required is 25D.

[0067] First, calculate the AX3 value of the eye axis corresponding to the same set of light rays passing through the cornea and the γ-zone biconvex lens: the refractive power of the γ-zone biconvex lens is 22D, and the curvature radius of the front and back surfaces is equal, forming a far focus for viewing distant objects; according to the thin biconvex lens theory, the optical center of the γ-zone biconvex lens is located at the geometric center of the intraocular lens. Fig.11As shown in the figure, the two light rays AA1 and BB1 are refracted by the cornea and the γ-zone biconvex lens (diopter +22D) and focused at f0 of the optical axis, forming a far focus. According to formula (2), d is generally the distance from the corneal vertex to the vertex of the front surface of the intraocular lens, in meters (m). The distance from the corneal vertex to the vertex of the front surface of the intraocular lens of the patient's right eye is 0.00457m; because the thickness of the intraocular lens is different, in order to increase the accuracy of the calculation results, we define d as the distance from the corneal vertex to the optical center of the intraocular lens. The distance from the vertex of the front surface of the intraocular lens to the optical center of the intraocular lens is equal to half of the thickness of the thickest part of the intraocular lens. If the thickness of the intraocular lens is 0.0012m, then the distance from the vertex of the front surface of the intraocular lens to the optical center is 0.0006m; therefore, the distance d from the corneal vertex to the optical center of the intraocular lens = the distance from the corneal vertex to the vertex of the front surface of the intraocular lens (0.00457m) + the distance from the vertex of the front surface of the intraocular lens to the optical center of the intraocular lens (0.0006m) = 0.00457m + 0.0006m = 0.00517m. In other words, the distance from the corneal vertex to the optical center of the γ zone lens is 0.00517m. According to formula (2), substitute the above data to calculate the eye axis A corresponding to looking at distant objects. X3 , and the result is A X3 =0.022692m(22.692mm). That is to say, the focus of the image formed by the light from the distant object through the cornea and the γ-zone biconvex lens is located on the optical axis 22.692mm behind the corneal vertex, that is, at f0 (retina) of the optical axis.

[0068] Next, calculate the eye axis A corresponding to the same set of light passing through the cornea and the α-zone biconvex lens X4 Value: The α zone is a biconvex lens, the curvature radius of the front and back surfaces is equal, and the combined refractive power of the front and back surfaces is +25D, forming a near focus. According to the thin biconvex lens theory, the optical center of the α zone biconvex lens is located at the geometric center of the intraocular lens. Please refer to the attached Fig.11As shown, the two light rays CC1 and DD1 pass through the α-zone biconvex lens respectively and are focused at f2 of the optical axis to form a near focus. According to formula (2), d is generally the distance from the corneal vertex to the vertex of the front surface of the intraocular lens. The distance from the corneal vertex to the vertex of the front surface of the intraocular lens of the patient's right eye is 0.00457. Because the thickness of intraocular lenses is different, in order to increase the accuracy of the calculation results, we define d as the distance from the corneal vertex to the optical center of the intraocular lens. The distance from the vertex of the front surface of the intraocular lens to the optical center of the intraocular lens is equal to half of the thickness of the intraocular lens. If the thickness of the intraocular lens is 0.0012m, then the distance from the vertex of the front surface of the intraocular lens of the α zone biconvex lens to the optical center is 0.0006m. Therefore, the distance from the corneal vertex to the optical center of the intraocular lens d = the distance from the corneal vertex to the vertex of the front surface of the intraocular lens (0.00457m) + the distance from the front surface of the intraocular lens to the optical center of the intraocular lens (0.0006m) = 0.00457m + 0.0006m = 0.00517m. That is to say, the distance from the corneal vertex to the optical center of the α zone is 0.00517 m. According to formula (2), substituting the above data, the eye axis A corresponding to the clear image at f2 after the light emitted by the distant object is refracted by the cornea and the α zone biconvex lens is calculated. X4 , and the result is A X4 =0.022029m(22.029mm). That is to say, the focus of the image formed by the light from the distant object through the cornea and the α-zone plano-convex lens is located on the optical axis 22.029mm behind the corneal vertex, that is, at f2 of the optical axis.

[0069] Calculate the distance Δ1=A between the focus f0 and the focus f2 of the comparative example X3 -A X4 =22.692mm-22.029mm=0.663mm.

[0070] The light emitted by the distant object is refracted by the cornea and the γ-zone biconvex lens (+22D) and converges at the far focus f0 to form a clear target image, and the far focus f0 is located on the retina. At the same time, the light emitted by the distant object is refracted by the cornea and the α-zone biconvex lens (+25D) and focused at the near focus f2. The light continues to propagate toward the far focus f0 (retina) and reaches the far focus f0 (retina) to form a defocused blurred image. The farther the near focus f2 is from the far focus f0 (that is, the larger Δ1 is), the more blurred the defocused blurred image is and the larger the range of the blurred image is. Therefore, the greater the interference to the clear target image at the far focus f0, the greater the visual interference generated, and the lower the imaging quality.

[0071] In the embodiment of the present invention, the light emitted by the distant object is refracted by the cornea and the φ zone biconvex lens (+22D) and converges at the far focus f0 to form a clear target image, and the far focus f0 is located on the retina. At the same time, the light emitted by the distant object is refracted by the cornea and the β zone plano-convex lens (+25D) and converges at the near focus f1. The light continues to propagate toward the retina and reaches the far focus f0 (retina) to form a defocused blurred image. When the near focus f1 is closer to the far focus f0 (that is, the smaller Δ is), the less blurred the defocused blurred image is and the smaller the range of the blurred image is, so the interference to the clear target image at the far focus f0 is smaller, and the visual interference generated is smaller, so that the imaging quality is higher. Δ=0.346mm, Δ1=0.663mm, compared with Δ1, Δ is reduced to 52.19% of Δ1, so the imaging quality of the embodiment of the present invention is obviously clearer than that of the comparative embodiment when looking far away.

[0072] The refractive multifocal intraocular lens provided by the embodiment of the present invention has at least the following advantages: (1) The refractive power of the second lens is greater than that of the first lens. The cornea and the first lens form a far focus, and the cornea and the second lens form a near focus. The optical center of the first lens and the optical center of the second lens are on the same optical axis, and the optical center of the second lens is located behind the optical center of the first lens, so that the distance between the near focus and the far focus (retina) is shortened. When looking at a distant object, the light emitted by the distant object passes through the cornea and the second lens (near vision optical zone) and is focused at the near focus. The light continues to propagate toward the far focus (retina) and forms a defocused blurred image when it reaches the far focus (retina). At the same time, the light emitted by the distant object is refracted by the cornea and the first lens (far vision optical zone) to form a clear target image at the far focus (retina). As the distance between the near focus and the far focus decreases, the defocused blurred image becomes less blurred and the range of the blurred image becomes smaller. Therefore, the defocused blurred image has less optical interference with the far focus target image, thereby improving the quality of the target image.

[0073] (2) The refraction principle is used to form an image, and the near optical zone is added with +3D of refractive power, which reduces visual interference and provides good far and near vision.

[0074] (3) The surface of the artificial lens has a smooth transition and no refraction ring or diffraction ring, which improves the imaging quality and light energy utilization and reduces optical interference phenomena such as scattering and glare.

[0075] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A refractive multifocal intraocular lens, characterized in that: include: The first lens forms a far vision optical zone, and the focus formed by the far vision optical zone and the cornea is a far focus; The second lens forms a near optical zone, and the focus formed by the near optical zone and the cornea is a near focus; The refractive power of the second lens is greater than that of the first lens, and the optical center of the second lens is located behind the optical center of the first lens, and the optical center of the first lens and the optical center of the second lens are on the same optical axis.

2. The refractive multifocal intraocular lens according to claim 1, characterized in that: The first lens is a biconvex lens, the second lens is a planoconvex lens with a flat front surface and a convex rear surface, and the biconvex lens is arranged in a circumferential direction of the planoconvex lens.

3. The refractive multifocal intraocular lens according to claim 2, characterized in that: The plano-convex lens is located in the central area of ​​the biconvex lens, or the plano-convex lens is located in the para-central area of ​​the biconvex lens.

4. The refractive multifocal intraocular lens according to claim 2, characterized in that: The plano-convex lens is located in the central area of ​​the biconvex lens, and the refractive power of the front convex surface of the biconvex lens is greater than the refractive power of the rear convex surface thereof.

5. The refractive multifocal intraocular lens according to claim 4, characterized in that: The refractive power of the front convex surface of the biconvex lens is 6D greater than the refractive power of the back convex surface thereof.

6. The refractive multifocal intraocular lens according to claim 1, characterized in that: The first lens is a first type biconvex lens, the second lens is a second type biconvex lens, and the refractive power of the rear convex surface of the second type biconvex lens is greater than the refractive power of the front convex surface thereof.

7. The refractive multifocal intraocular lens according to claim 6, characterized in that: The first type of biconvex lens is arranged in a circumferential direction of the second type of biconvex lens, the second type of biconvex lens is located in the central area of ​​the first type of biconvex lens, the refractive power of the front convex surface of the first type of biconvex lens is greater than the refractive power of the rear convex surface, and the refractive power of the rear convex surface of the second type of biconvex lens is greater than the refractive power of the front convex surface.

8. The refractive multifocal intraocular lens according to claim 7, characterized in that: The refractive power of the front convex surface of the first type of biconvex lens is 6D greater than the refractive power of the back convex surface thereof, and the refractive power of the back convex surface of the second type of biconvex lens is 6D greater than the refractive power of the front convex surface thereof.

9. The refractive multifocal intraocular lens according to claim 6, characterized in that: The second type of biconvex lens is arranged in a circumferential direction of the first type of biconvex lens, the first type of biconvex lens is located in the central area of ​​the second type of biconvex lens, the refractive power of the front convex surface of the first type of biconvex lens is greater than the refractive power of the rear convex surface, and the refractive power of the rear convex surface of the second type of biconvex lens is greater than the refractive power of the front convex surface.

10. The refractive multifocal intraocular lens according to claim 1, characterized in that: The first lens is a first type plano-convex lens with a convex front surface and a flat rear surface, and the second lens is a second type plano-convex lens with a flat front surface and a convex rear surface.

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