Intraocular lens

Abstract

The utility model relates to the technical field of intraocular lenses, in particular to a diffraction type multi-focus intraocular lens. According to the multi-focus intraocular lens capable of reducing the bad optical phenomenon, achromatism and even zero chromatic aberration are achieved by adjusting the matching degree between the refractive index of the material and the additional focal power of the diffraction perifocus, and therefore the glare occurrence rate of the diffraction type multi-focus intraocular lens is greatly reduced, and the optical quality of the diffraction type multi-focus intraocular lens is improved. Good far-near vision or far-middle-near whole-course vision is obtained after the operation, and the visual quality satisfaction degree after the operation is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of artificial lens, especially a multifocal artificial lens for cataract treatment, in particular to a diffractive multifocal artificial lens. BACKGROUND

[0002] Cataract is a common senile disease and the leading cause of blindness worldwide. Surgery is the only effective method for treating cataract. Modern cataract surgery is performed by phacoemulsification and implantation of an artificial lens to replace the natural lens that has become cloudy. After the natural lens of cataract is removed, the human eye has other refractive needs in addition to the correction of refractive errors, such as aberration, astigmatism, and presbyopia correction. With the improvement of people's living standards and the development of technology, modern artificial lenses have various design types, including aspherical surfaces for correcting aberrations, Toric for correcting astigmatism, and multifocal for correcting presbyopia. The correction of astigmatism and presbyopia are both high-end refractive functions. High-end refractive function artificial lenses generally have high requirements for surgical operation and lens design, especially multifocal artificial lenses. Due to the light splitting mechanism and the addition of various non-smooth surface types on the optical surface, this type of artificial lens often accompanies unavoidable glare problems, which affect the visual quality of patients after surgery. The probability of glare after surgery with existing multifocal artificial lenses is as high as 50% or more, which requires patients to adapt for a long time and select patients based on their own conditions, such as personality and tolerance. Therefore, the use and promotion of multifocal artificial lenses are severely limited by adverse optical phenomena such as glare and halo. How to improve the optical performance of high-end refractive artificial lenses and reduce / adverse optical phenomena after multifocal artificial lens surgery is an important issue faced by the industry.

[0003] To reduce adverse optical phenomena, existing multifocal artificial lenses often make phase adjustments on the surface shape of the diffractive ring. For example, the patent US11 / 259524 of Johnson & Johnson Vision Care, Inc. uses a smooth structure on the diffractive surface to reduce glare. Or the patent US12109107B2 of Alcon uses a structure with gradually changing height of the diffractive ring to reduce glare interference. Or the additional optical power is made very small (such as Symfony of Johnson & Johnson, patent number US8,747,466B2) to reduce the density of the diffractive ring and reduce glare. However, these measures have limited effect on one hand, and on the other hand, the additional optical power affects the near vision ability of the human eye. Sacrificing the additional optical power to obtain better visual quality does not really solve the problem.

[0004] Therefore, the utility model is proposed. Utility model content

[0005] To solve the above technical problems, the utility model provides a kind of multifocal intraocular lens capable of reducing adverse optical phenomena, which can greatly reduce the occurrence rate of glare of diffractive multifocal intraocular lens, and improve the postoperative visual quality satisfaction while obtaining good distance and near vision or full-range distance and near vision.

[0006] Specifically, the technical solutions of the utility model are as follows:

[0007] The utility model provides a kind of multifocal intraocular lens, its surface is equipped with the diffractive structure for providing multiple focal points, the material of its intraocular lens is <100MV / mm 2 ; and the material refractive index of intraocular lens and diffractive near focal point additional optical power satisfy the following relationship:

[0008] ;

[0009] Wherein, n is material refractive index, ADD is the difference between the optical power of the nearest focal point and the far focal point provided by diffractive structure, i.e.

[0010] The utility model creatively finds the compensation mechanism of chromatic aberration and refractive chromatic aberration of diffractive multifocal point, and by adjusting the matching relationship of the two, the purpose of eliminating or reducing the chromatic aberration of multifocal point crystal is achieved, and achromatism or 0 chromatic aberration is realized. When the material refractive index is between 1.43~1.46, the diffractive near focal point additional optical power is between 1.0~3.2D; when the material refractive index is between 1.47~1.49, the diffractive near focal point additional optical power is between 2.0~4.2D; when the material refractive index is between 1.50~1.55, the diffractive near focal point additional optical power is between 3.6~6.3D. The multifocal intraocular lens designed by using this matching relationship can greatly reduce the occurrence rate of glare of diffractive multifocal intraocular lens.

[0011] Preferably, the material of the intraocular lens at least meets ≤1 grade in terms of sparkle level; wherein, when the sparkle of the intraocular lens is <50MV / mm 2 , it is defined as 0 grade; when the sparkle is >50MV / mm 2 , <100MV / mm 2 , it is defined as 1 grade; when the sparkle is >100MV / mm 2 , <200MV / mm 2 , it is defined as 2 grade; when >200MV / mm 2 , it is defined as 3 grade. The characteristics of material sparkle level ≤1 grade, preferably 0 grade, can reduce the glare of multifocal intraocular lens.

[0012] Preferably, the intraocular lens has a material refractive index between 1.46 and 1.48 and a diffractive near point add power between 2.0 and 3.6 D. The intraocular lens of this preferred interval range is more suitable for making a multifocal design.

[0013] Preferably, the intraocular lens is made of a hydrophobic acrylate material without blue light absorber and has a material refractive index between 1.43 and 1.55 or between 1.47 and 1.48.

[0014] Preferably, the material of the intraocular lens has a water content of ≤1%, preferably ≤0.5%.

[0015] The hydrophobic acrylate material without blue light absorber, i.e. without blue light shielding, is used in the utility model, which is more helpful to reduce the negative optical phenomena caused by the material.

[0016] Preferably, the diffractive structure is arranged on the back surface of the intraocular lens. Compared with the front surface, placing the diffractive ring on the back surface can further reduce the reflection and refraction of light on the diffractive surface and reduce stray light.

[0017] Preferably, the diffractive structure is composed of a diffractive ring, which is located within a 5mm diameter range of the center of the optical zone of the intraocular lens, and more preferably within a 4.5mm diameter range of the center of the optical zone of the intraocular lens.

[0018] The utility model places the diffractive structure (which can be a diffractive ring) on the local area of the back surface of the optical part of the intraocular lens, which can further reduce the reflection and refraction of stray light. Especially by using a hydrophobic acrylate material without blue light absorber, i.e. without blue light shielding, and with a flash ≤1 level or even 0 flash, the negative optical phenomena caused by the material can be significantly reduced. In summary, the glare incidence of the diffractive multifocal intraocular lens can be further reduced, and the postoperative visual quality satisfaction can be improved while obtaining good far, intermediate and near vision.

[0019] As a more preferred embodiment, the material has a refractive index of 1.430±0.004 and a diffractive near point add power of 1.8-2.6 D, and the obtained intraocular lens is 0 color difference.

[0020] As another more preferred embodiment, the material has a refractive index of 1.475±0.004 and a diffractive near point add power of 2.5-3.4 D, and the obtained intraocular lens is 0 color difference.

[0021] As another more preferred embodiment, the material has a refractive index of 1.500±0.004 and a diffractive near point add power of 3.8-4.6 D, and the obtained intraocular lens is 0 color difference.

[0022] Further preferably, in the utility model, the diffractive structure further has at least one of the following (1)~(8) shown features:

[0023] (1) the diffractive structure includes multiple sets of diffractive rings, wherein the distance between the adjacent diffractive rings of the set of diffractive rings farthest apart is 0.16~0.66mm, or 0.19~0.49mm, or 0.22~0.40mm;

[0024] (2) the diffractive structure includes multiple sets of diffractive rings, wherein the height of the set of diffractive rings farthest apart is 0.77~3.51μm, or 0.77~3.33μm;

[0025] (3) the diffractive structure provides two focal points, far and near; or, provides three focal points, far, middle and near; or, provides more than three focal points;

[0026] (4) the diffractive structure provides a distance between adjacent focal points ≥1.5D;

[0027] (5) the light energy distribution ratio of the diffractive structure at the near focal point is 30%~50% or 30%~40%;

[0028] (6) the light energy distribution ratio of the diffractive structure at the far focal point is 50%~60%;

[0029] (7) the light energy distribution ratio of the diffractive structure at the middle focal point is 0%~20%;

[0030] (8) the near focal point provided by the diffractive structure has an additional optical power of 1~4D or 2.0~4.2D or 3.2D.

[0031] As a preferred embodiment, the utility model provides an intraocular lens for far, middle and near three focal points, and the material refractive index is 1.475±0.005;The near focal point additional optical power is 4.2±0.04D, and the middle focal point additional optical power is 2.1±0.04D;The near focal point diffractive ring height is 2.3±0.04μm;The middle focal point diffractive ring height is 1.2±0.04μm.

[0032] As a more preferred embodiment, the utility model provides an intraocular lens for far, middle and near three focal points, and the material refractive index is 1.475±0.005;The near focal point additional optical power is 3.2±0.04D, and the middle focal point additional optical power is 1.6±0.04D;The near focal point diffractive ring height is 2.3±0.04μm;The middle focal point diffractive ring height is 1.2±0.04μm.

[0033] Preferably, the surface of the intraocular lens is provided with any optical surface type of toric surface, aspheric surface, spherical surface.

[0034] Preferably, the intraocular lens is made using a turning process.

[0035] Advantages:

[0036] The utility model provides a multi -focus intraocular lens of reducing bad optical phenomenon, through adjusting the matching degree between material refractive index and diffraction near focus additional optical power, achromatic or even 0 chromatic aberration, thereby greatly reduce the glare incidence rate of diffraction type multi -focus intraocular lens, obtain good far vision or near vision or far near full range vision after operation, improve the visual quality satisfaction after operation. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to more clearly illustrate the technical scheme in the utility model or prior art, below will be to the drawing needed to be used in the embodiment or prior art description.

[0038] Figure 1 It is excellent material chromatic aberration control schematic diagram.

[0039] Figure 2 It is acceptable material chromatic aberration limit schematic diagram.

[0040] Figure 3 It is the material refractive index of crystal preparation material and the matching degree of crystal additional optical power schematic diagram, in the drawing, cutoff: chromatic aberration can be perceived by human eye, clock-shaped coverage area: not more than the resolution limit of human eye, the chromatic aberration produced by diffraction ≈ the chromatic aberration produced by refraction.

[0041] Figure 4 It is the MTF schematic diagram of crystal in actual eccentricity condition when diffraction ring is located at front surface and rear surface.

[0042] Figure 5 It is the PSF point spread function schematic diagram of crystal in different resolution condition when diffraction ring is located at front surface and rear surface.

[0043] Figure 6 It is the scintillation and its grade schematic diagram, in the drawing, (a) is 0 grade, (b) is 1 grade, (c) is 2 grade.

[0044] Figure 7 It is the comparative schematic diagram of postoperative 12 months contrast sensitivity of two groups of subjects participating in clinical test.

[0045] Figure 8 It is the comparative schematic diagram of postoperative 12 months visual adverse symptoms of two groups of subjects participating in clinical test.

[0046] Figure 9 It is the structure schematic diagram of trifocal intraocular lens described in embodiment 1.

[0047] Figure 10A schematic view of the structure of the bifocal astigmatism correcting intraocular lens described in Example 2. DETAILED DESCRIPTION

[0048] The preferred embodiments of the present application will be described in detail with reference to the following examples. It should be understood that the following examples are given for illustrative purposes only and are not intended to limit the scope of the present application. Those skilled in the art can make various modifications and substitutions to the present application without departing from the spirit and principles of the present application.

[0049] The source of the adverse visual phenomenon of the diffractive multifocal intraocular lens implanted in the human eye can be from many aspects, mainly including: (1) optical interference between multiple focal points; (2) chromatic aberration of the lens; (3) non-smooth diffractive surface, after the incident light passes through, refraction and reflection occur, causing chaotic light interference; (4) other defects of the material itself, such as fluorescence. Among them, the phenomena of chromatic aberration and fluorescence also exist in ordinary single-focus, but due to the mechanism of diffraction multifocal light distribution, the light energy allocated to each focal point is relatively small, and the optical quality is low, which can magnify various optical defects of the lens, and further cause adverse phenomena. Therefore, chromatic aberration and fluorescence are not perceived by patients after implantation of ordinary single-focus lenses, but they often become complaints on multifocal lenses.

[0050] The present application finds the compensation mechanism of the chromatic aberration of the diffractive multifocal and the refractive chromatic aberration, and obtains the matching relationship therebetween, thereby achieving the purpose of eliminating or reducing the chromatic aberration of the multifocal lens; by placing the diffractive ring (which constitutes the diffractive structure of the present application) in the local area of the rear surface of the optical part of the intraocular lens, further reducing the reflection and refraction of stray light; by using a hydrophobic acrylic ester material without blue light absorber, i.e. without blue light shielding, fluorescence ≤1 level or even 0 fluorescence, reducing the negative optical phenomena caused by the material, and comprehensively, the glare incidence rate of the diffractive multifocal intraocular lens is greatly reduced, and good far, intermediate and near vision is obtained after the operation, and the postoperative visual quality satisfaction is improved.

[0051] The technical solutions of the present application will be described in detail below in combination with theoretical analysis and specific examples.

[0052] (1) Compensation mechanism of chromatic aberration of diffractive multifocal and refractive chromatic aberration and matching relationship thereof

[0053] Chromatic aberration refers to the phenomenon that different wavelengths of light converge at different points after passing through an optical medium, causing optical path difference. In a multifocal intraocular lens, it is a combination of two optical mechanisms, namely refraction and diffraction, so the chromatic aberration is divided into two parts, one is the chromatic aberration caused by the material itself, called refractive chromatic aberration, and the other is the chromatic aberration caused by the diffractive ring, called diffractive chromatic aberration.

[0054] Wherein the refractive chromatic aberration is related to optical power, and the optical power is calculated according to the following formula: φ = (n' - n) / r Wherein, φ is the optical power, n' is the refractive index of the artificial lens material, n is the refractive index of the medium in which the lens is located, and r is the radius of curvature of the surface of the artificial lens.

[0055]

[0056] It can be seen that the convergence point is related to the refractive index of the medium, and the smaller the refractive index of the medium, the farther the convergence point. The longer the wavelength (red light), the smaller the refractive index, and the farther the convergence point. Chromatic aberration direction: red, orange, yellow, green, blue, indigo and violet.

[0057] The focal length of diffraction is calculated according to the following formula: f = λ / (2πN) Wherein, f is the focal length, R is the radius of the Nth ring; N is the number of diffraction rings, and λ is the wavelength.

[0058]

[0059] It can be seen that the chromatic aberration of diffraction is inversely proportional to the wavelength, the longer the wavelength, the shorter the focal length, and the closer the convergence point; the chromatic aberration of diffraction is related to the additional optical power, and the higher the additional optical power, the more serious the chromatic aberration.

[0060] It can be further known that the chromatic aberration of refraction is opposite to that of diffraction, and the chromatic aberration of the diffractive multifocal intraocular lens can be compensated for each other. However, not all chromatic aberrations of refraction and diffraction can be compensated for each other, and need to reach a degree that cannot be recognized by the human eye, so as to realize "achromatic". The calculation method adopts ray tracing, a standard human eye model is established in Zemax according to the standard human eye, and different refractive index artificial lenses are placed in the standard human eye model, and the residual chromatic aberration after combination of different refractive index and different additional optical power is calculated. Among them, the central wavelength used in the calculation is 550nm, and the limit wavelength is 380nm~780nm (i.e. visible light). When the defocus caused by the residual chromatic aberration after compensation is greater than the resolution of the human eye (about 10 wavelengths of the retina), the chromatic aberration can be perceived by the human eye, and the color difference is considered unacceptable; when the defocus caused by the residual chromatic aberration after compensation is less than the resolution of the human eye, it is considered "achromatic", and the diffraction additional optical power and the refractive index match well; when the defocus caused by the residual chromatic aberration after compensation is 0, it is considered "0 chromatic aberration", and the diffraction design and the refractive design match best. As shown in the following formula: Figure 1 And Figure 2

[0061] ​The utility model discloses creatively obtained, when the refractive index of the preparation material of artificial lens is between 1.43~1.46, the near focus additional optical power is between 1.0~3.2D, can reach achromatism, further, when the refractive index is 1.43, the near focus additional optical power is between 1.8~2.6D, then chromatic aberration compensation degree is better, nearly reaches 0 chromatic aberration result. When the material refractive index is between 1.47~1.49, the near focus additional optical power is between 2.0~4.2D, can reach achromatism, further, when the refractive index is 1.475, the near focus additional optical power is between 2.5~3.4D, then chromatic aberration compensation degree is better, nearly reaches 0 chromatic aberration result. When the material refractive index is between 1.50~1.55, the near focus additional optical power is between 3.6~6.3D, can reach achromatism, further, when the refractive index is 1.50, the near focus additional optical power is between 3.8~4.6D, then chromatic aberration compensation degree is better, nearly reaches 0 chromatic aberration result. Above all, it can be obtained that the near focus additional optical power provided by the diffraction structure is matched with the refractive index of the preparation material of artificial lens, and both satisfy the following relation:

[0062] .

[0063] Wherein, n is the refractive index of the material for preparing artificial lens, and ADD is the difference between the optical power of the nearest focus and the far focus provided by the diffraction structure (the diffraction ring in the utility model) of the multifocal artificial lens, that is, the near focus additional optical power.

[0064] The near focus of multifocal artificial lens is related to near vision ability, and the higher the additional optical power is, the stronger the near vision ability is, and the nearer the near vision distance is. At present, the requirement of human eye near vision ability is generally between 2D and 3.6D, so when the refractive index of the crystal material is between 1.46 and 1.48, it is more suitable for making multifocal design. Figure 3 As shown in the figure, the refractive index of the crystal material is high, the material chromatic aberration is most difficult to balance, and needs very high additional optical power, and usually shows excess refraction chromatic aberration.

[0065] (2) Diffraction ring placement position and distribution

[0066] The diffraction structure arranged on the surface of the optical part of the artificial lens is a non-smooth structure, has a stepped property, when light is incident to the artificial lens, the inclined surface of the diffraction stepped structure itself can reflect light to various angles, and meanwhile, light passes through the diffraction ring, and also causes chaotic refracted light, and these are the sources of glare caused by multifocal lens stray light.

[0067] The diffraction ring structure is placed on the front surface and the rear surface of the crystal, and the degree of harm caused by stray light is different. The utility model discloses a kind of diffractive multifocal intraocular lenses, which is simulated and studied in depth by the way of zemax simulation and ray tracing.For example, two multifocal intraocular lenses are designed, and the material, refractive power, central thickness, optical zone size and additional optical power of the intraocular lenses are the same, wherein the refractive index of the crystal is 1.475, the optical zone diameter is 6.0mm, the central thickness is 0.8mm, the refractive power is +20.0D, the bifocal design is adopted, the additional optical power is 3.2D, the diffraction ring height is 1.72μm, and the light energy distribution of far: near = 60:40 is provided.The only difference between the two crystals is that the diffraction ring of one of them is located on the front surface of the optical zone of the crystal, and the diffraction ring of the other is located on the rear surface of the optical zone of the crystal.The crystal is placed in a standard human eye model, and the MTF and PSF point spread function of the crystal under actual decentration and different resolutions are observed, and it is found that when the diffraction ring of the crystal is located on the rear surface, the MTF under each resolution under decentration condition is higher, and the PSF point spread function is more ideal, as shown in Figure 4 and Figure 5 .

[0068] Therefore, compared with the diffraction ring arranged on the front surface of the lens, the diffraction ring of the diffractive multifocal intraocular lens is located on the rear surface of the artificial lens, which can reduce the reflection and refraction of the diffraction surface to light, reduce stray glare, and is beneficial to improve the optical performance.

[0069] (3) Material properties

[0070] Flash is a common problem of hydrophobic acrylate, due to the process caused by the gap between the molecules of the material during the synthesis of the material, when the gap reaches a certain amount and a certain volume, the crystal will present a "star" state under light conditions, which is called "flash" in the industry.According to international testing methods, when the flash of artificial lens is < 50MV / mm 2 , it is defined as level 0; when the flash is > 50MV / mm 2 , < 100MV / mm 2 , it is defined as level 1 flash; when the flash is > 100MV / mm 2 , < 200MV / mm 2 , it is defined as level 2 flash; when > 200MV / mm 2 , it is defined as level 3 flash. Figure 6As shown, (a), (b), (c) are respectively close to 0 peridot (0 level), peridot control better (1 level), peridot larger (2 level) state. Peridot phenomenon occurs universally in the field of intraocular lenses, when the material with peridot is applied to a single-focus intraocular lens, because the resolution that the crystal itself can reach is higher, the human eye is not sensitive, so the phenomenon is generally observed by the doctor after the operation, under the slit lamp, most patients have no experience and clinical complaints. However, due to the light splitting mechanism, the optical resolution (MTF) of the multifocal intraocular lens is reduced by 60% or more, and the existence of peridot will be strengthened by the multifocal mechanism, thereby affecting the visual quality of the patient. For example, in clinical practice, the Alcon crystal has a high refractive index of 1.55, and is molded, the material itself has a lower peridot level, and the peridot research test results of the material Acrysof material (SN60WF) are 61 ± 33 MVs / mm 2 , only 2 levels and above, when applied to a multifocal lens, more glare phenomenon is often observed. Therefore, the utility model provides that during the production and manufacturing of the multifocal intraocular lens, a peridot level ≤1 level, preferably 0 peridot (≤1.8 ± 0.9 MV / mm 2 ) is used for manufacturing.

[0071] Further, the forming of the intraocular lens is divided into a molding process and a turning process, the molding process is to directly inject a single body into a mold to directly form an intraocular lens, and the process is more prone to have water and air entering the mold during synthesis, thereby causing more peridot; the utility model preferably adopts the turning process, a large piece of material is first manufactured, and then the material is turned into a small intraocular lens, the process is more stable during synthesis, and the material is more uniform inside, air and water are not easy to enter, thereby causing less peridot phenomenon, and the process is more suitable for manufacturing a multifocal intraocular lens.

[0072] In addition, although the hydrophobic acrylate material is named hydrophobic, it also has a certain water content, in the industry, a water content less than 1% is generally considered as a hydrophobic material. If the hydrophobic material maintains a certain water content, the interstitial space of the crystal that forms peridot will be filled with water in the crystal after the crystal is implanted, thereby eliminating peridot, so the appropriate water content of the hydrophobic material can also eliminate peridot, but the increase of the water content will cause problems such as power drift, preservation, sterilization, etc. Therefore, the multifocal intraocular lens of the utility model preferably uses a hydrophobic acrylate with a water content of ≤0.5%.

[0073] In addition, the height / width of the diffraction ring of the intraocular lens is matched with the refractive index of the material, and a better achromatic effect can be achieved.

[0074] The utility model discloses above -mentioned, in the production and manufacture of multifocal intraocular lens, adopt the flash grade <=1 level, preferably, 0 grade flash (<=1.8+0.9 MV / mm 2 ) make;And / or, adopt the hydrophobic acrylate of water content <=1% preferably, water content <=0.5% and make the artificial lens;And / or, adopt the turning process and process the artificial lens, can significantly eliminate the effect of flash, and then reduce the glare of multifocal intraocular lens.

[0075] As Figure 7 And Figure 8 Shown, adopt the embodiment of the utility model, observe the adverse visual phenomena such as postoperative glare, halo of patient in clinical test, find that it is obviously more superior in contrast sensitivity, glare, adverse visual symptoms, postoperative satisfaction compared with the prior art in the industry.

[0076] Among them, Figure 7 It is the comparison result of postoperative 12 months of contrast sensitivity of two groups of subjects (left graph: dark light;Right graph: dark light glare;N.s. represents that difference is not statistically significant, * represents p <0.05). Experiment sets 4 kinds of background light, is bright light (85cd / m 2 ), bright light glare (135Lux), dark light (3cd / m 2 ), dark light glare (28Lux);Set 5 kinds of spatial frequency, are 1.5c / d, 3.0c / d, 6.0c / d, 12.0c / d, 18.0c / d. Experimental results show that: 12 months after operation, the test group under dark light condition 6.0c / d is significantly higher than the control group ( p <0.05), there is no statistical difference between groups under other background light conditions and spatial frequency ( p >0.05).

[0077] Figure 8 It is the comparison result of adverse visual symptoms of two groups of subjects after 12 months of operation (n.s. represents that difference is not statistically significant, * represents p <0.05). Experimental evaluation method: 5 kinds of adverse visual phenomena (halo, glare, blurred vision, ghosting, diplopia) are graded according to 5 degrees (none, lighter, light, medium, heavy). Experimental results show that: 12 months after operation, the glare degree of the test group is significantly lower than the control group ( p <0.05), there is no statistical difference between groups in other adverse visual symptom evaluation indexes ( p >0.05).

[0078] Example 1

[0079] The embodiment provides a trifocal intraocular lens.

[0080] The trifocal intraocular lens provided by the embodiment is made of hydrophobic acrylate, the material refractive index is 1.475, the water content is <0.5%, the lens is formed by turning process, the main refractive power of the lens body is +20.0D, the optical zone diameter is 6.0mm, the front surface is a conventional aspheric surface, the rear surface has a diffraction ring in the range of an optical zone diameter of 4.5mm, the diffraction area accounts for 75% of the total optical area, there are 16 diffraction rings in total, which are 2 sets of rings, providing three focal points of far, middle and near, wherein the additional optical power (ADD) of the near focal point is 4.2D, which is composed of 11 rings with odd intervals of 1, 3, 5…21, the ring height is 2.3μm, and 30% of the light energy is distributed to the near focal point; the additional optical power (ADD) of the middle focal point is 2.1D, which is composed of 11 rings with intervals of 2, 4, 6…22, the ring height is 1.2μm, and 20% of the light energy is distributed to the middle focal point. The final far focal point obtains 50% of the light energy. The diffraction ring parameters are shown in Table 1. The lens structure is shown in Figure 9 .

[0081]

[0082] It can be known from the zemax simulation that the additional optical power of the near focal point of the trifocal diffractive intraocular lens is well matched with the material refractive index, the residual chromatic aberration formed by the additional optical power of the far focal point and the material refractive index in the human eye is 2.53 wavelengths, close to 0 chromatic aberration, and the achromatic effect is good.

[0083] In the embodiment, the diffraction ring of the lens does not occupy the full area of the optical part, in the range of 4.5mm in diameter, the far vision is mainly considered, the near focal point is auxiliary, and the middle focal point has the lowest proportion, because the matching degree of the additional optical power of the middle focal point and the material refractive index is general, in order to prevent more chromatic aberration, the light energy proportion is reduced. In the range of 4.5-6.0mm, the energy is mainly distributed in the far focal point, the energy distribution proportion of the far focal point is increased, the good distance vision under dark light condition is ensured, and the glare is reduced.

[0084] In the embodiment, the refractive power of the far focal point of the intraocular lens can be between-10~+40D, preferably-10~+36D, more preferably 5~30D. At the same time, the trifocal design can also be combined with other optical designs, such as adopting astigmatic complex curve design and EDF aspheric surface design on the front surface, so as to correct astigmatism of the human eye while providing far, middle and near focal points.

[0085] In the same way as the embodiment, it is conceivable that the near vision additional power of the crystal made of the hydrophobic acrylate with the refractive index can be between 2.5D and 3.4D, and good chromatic aberration compensation can be achieved. When other materials are used to make similar trifocal crystals, the chromatic aberration compensation of the near focus is used as the limit of the design. When the refractive index of the material is between 1.43 and 1.46, the near focus additional power is between 1.0 and 3.2D; when the refractive index of the material is between 1.47 and 1.49, the near focus additional power is between 2.0 and 4.2D; when the refractive index of the material is between 1.50 and 1.55, the near focus additional power is between 4 and 6.3D.

[0086] Embodiment 2

[0087] The embodiment provides a bifocal astigmatism correction intraocular lens.

[0088] The intraocular lens described in the embodiment is made of hydrophobic acrylate, the material has a refractive index of 1.48 and a water content of <0.5%, and is formed by turning process. The main dioptric power of the crystal body is +20.0D, the optical zone diameter is 6.0mm, the front surface is toric, and the toric surface equation is:

[0089] .

[0090] Wherein c1 is the curvature of the rotation axis, and c2 is the curvature of the generatrix. The optical surface of the intraocular lens is taken as the X-Y plane, and z is the axial thickness direction. The cylindrical power of the crystal is 1.5D, the radius of curvature in the main mirror direction is 18.459mm, and the radius of curvature in the cylindrical direction is 15.548mm.

[0091] The rear surface has a diffraction ring in a range of 4.0mm optical zone diameter, the diffraction area accounts for 66.7% of the total optical area, there are 9 diffraction rings in total, and the diffraction rings provide two focus points of far and near, wherein the near focus additional power (ADD) is 3.2D, the ring height is 1.78μm, 40% of the light energy is distributed to the near focus point, and 60% of the light energy is obtained by the far focus point. The diffraction ring parameters are shown in Table 2. The crystal structure is shown in Figure 10 .

[0092]

[0093] It can be known from the zemax simulation that the near focus additional power of the bifocal diffractive intraocular lens matches well with the refractive index of the material, the residual chromatic aberration formed by the additional power and the refractive index of the material in the human eye is 0.6 wavelengths, and the achromatic effect is good.

[0094] In this embodiment, the diffraction ring of the crystal does not occupy the full area of the optical part, and in the range of 4.0 mm in diameter, the far vision is mainly considered. In the range of 4.0-6.0 mm, the energy is mainly distributed in the far focal point, and the proportion of the far focal point energy distribution is increased, which ensures good far vision in dark light conditions and reduces glare.

[0095] In this embodiment, the far focal point diopter of the intraocular lens can be between -10 and +40 D, preferably between -10 and +36 D, and more preferably between 5 and 30 D.

[0096] Under the same idea as this embodiment, it is conceivable that when such a crystal is made of a hydrophobic acrylate with such a refractive index, the near additional optical power of the crystal can be between 2.0 and 4.2 D, all of which can achieve a good chromatic aberration compensation degree, especially when the additional optical power is between 2.6 and 3.5 D, which is close to 0 chromatic aberration. When other materials are used to make similar trifocal crystals, the near focal point chromatic aberration compensation degree is used as the limit of the design. When the material refractive index is between 1.43 and 1.46, the near focal point additional optical power is between 1.0 and 3.2 D; when the material refractive index is between 1.47 and 1.49, the near focal point additional optical power is between 2.0 and 4.2 D; when the material refractive index is between 1.50 and 1.55, the near focal point additional optical power is between 3.6 and 6.3 D.

[0097] Embodiment 3

[0098] This embodiment provides a bifocal intraocular lens.

[0099] The bifocal intraocular lens described in this embodiment is made of a hydrophobic acrylate, the material has a refractive index of 1.50 and a water content of <0.5%, and is formed by turning process. The main body of the crystal has a refractive power of +15.0 D, the optical zone diameter is 6.0 mm, the front surface is spherical, and the rear surface has a diffraction ring in the range of 4.0 mm optical zone diameter. The diffraction area accounts for 66.7% of the total optical area, there are 20 diffraction rings in total, and the diffraction ring provides far and near focal points, wherein the near focal point additional optical power (ADD) is 3.6 D, the ring height is 1.68 μm, and 50% of the light energy is distributed to the near focal point. The diffraction ring parameters are shown in Table 3.

[0100]

[0101] Through zemax simulation, it can be known that the near focal point additional optical power of the bifocal diffractive intraocular lens matches well with the material refractive index, the residual chromatic aberration formed by the additional optical power and the material refractive index in the human eye is 2 wavelengths, and the chromatic aberration elimination is good.

[0102] In the embodiment, the diffraction ring of the crystal does not occupy the whole area of the optical part, and the diffraction ring is mainly in the range of 4.0 mm in diameter. In the range of 4.0-6.0 mm, the energy is mainly distributed in the far focal point, and the proportion of the energy distribution in the far focal point is increased, so that good far vision is ensured in dark light conditions, and glare is reduced.

[0103] In the embodiment, the far focal point diopter of the artificial lens can be between-10 and +40D, preferably between-10 and +36D, and more preferably between 5 and 30D.

[0104] In the same way as the embodiment, it is conceivable that when the hydrophobic acrylic ester with the refractive index is used to make the crystal, the near distance additional optical power of the crystal can be between 2.4 and 4.6D, and good chromatic aberration compensation can be achieved, especially when the additional optical power is between 2.8 and 3.6D, which is close to 0 chromatic aberration.

[0105] Finally, it should be pointed out that the above embodiments are only used to illustrate the technical solutions of the present application, and are not limited thereto. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features can be replaced by equivalent ones. These modifications or replacements do not change the essence of the corresponding technical solutions, and do not deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. An artificial lens, the surface of which is provided with a diffraction structure for providing multiple focal points, characterized in that, The diffraction structure consists of diffraction rings disposed on the posterior surface of the intraocular lens, and the refractive index of the intraocular lens material and the additional optical power near the diffraction focal point satisfy the following relationship: ； Where n is the refractive index of the material, and ADD is the difference in optical power between the nearest focal point and the far focal point provided by the diffraction structure, i.e., the additional optical power at the near focal point.

2. The intraocular lens according to claim 1, characterized in that, The diffraction structure is located within a 5mm diameter range from the center of the optical zone of the intraocular lens; or, the diffraction structure is located within a 4.5mm diameter range from the center of the optical zone of the intraocular lens.

3. The intraocular lens according to claim 2, characterized in that, The diffraction structure consists of multiple sets of diffraction rings, with the set of diffraction rings being the most distant. The spacing between adjacent diffraction rings is 0.16~0.66 mm, or 0.19~0.49 mm, or 0.22~0.40 mm.

4. The intraocular lens according to claim 2, characterized in that, The diffraction structure consists of multiple sets of diffraction rings, with the set of diffraction rings having the largest distance between them having a height of 0.77~3.51μm or 0.77~3.33μm.

5. The intraocular lens according to claim 2, characterized in that, The diffraction structure provides two focal points, one near and one far. Alternatively, it can provide three focal points: far, medium, and near. Alternatively, provide more than 3 focal points; the spacing between adjacent focal points provided by the diffraction structure is ≥1.5D.

6. The intraocular lens according to claim 1, characterized in that, The refractive index of the material of the intraocular lens is between 1.46 and 1.48, and the additional optical power near the diffraction focal point is between 2.0 and 3.6D; Alternatively, the refractive index of the intraocular lens is 1.430±0.004, the additional optical power near the diffraction focal point is between 1.8 and 2.6D, and there is 0 chromatic aberration; Alternatively, the material has a refractive index of 1.475±0.004, an additional optical power near the diffraction focal point between 2.5 and 3.4D, and zero chromatic aberration; Alternatively, the material has a refractive index of 1.500±0.004, an additional optical power near the diffraction focal point of 3.8~4.6D, and 0 chromatic aberration.

7. The intraocular lens according to any one of claims 1-6, characterized in that, The surface of the artificial lens is provided with any optical surface type, such as an annular surface, aspherical surface, or spherical surface.

8. The intraocular lens according to any one of claims 1-6, characterized in that, The light energy distribution ratio of the diffraction structure is 30%~50% or 30%~40% near the focal point, 50%~60% at the far focal point, and 0%~20% at the mid focal point.

9. The intraocular lens according to any one of claims 1-6, characterized in that, The diffraction structure provides an additional near-focal power of 1~4D, 2.0~4.2D, or 3.2D.

10. The intraocular lens according to any one of claims 1-6, characterized in that, The intraocular lens is a trifocal intraocular lens with a far, intermediate, and near focal length. Its material refractive index is 1.475±0.005; the additional optical power at the near focal point is 4.2±0.04D, and the additional optical power at the intermediate focal point is 2.1±0.04D; the height of the diffraction ring at the near focal point is 2.3±0.04μm; and the height of the diffraction ring at the intermediate focal point is 1.2±0.04μm. Alternatively, the intraocular lens is a trifocal intraocular lens with a far, intermediate, and near focal length, and its material refractive index is 1.475±0.005; the near focal additional optical power is 3.2±0.04D, the intermediate focal additional optical power is 1.6±0.04D; the near focal diffraction ring height is 2.3±0.04μm; and the intermediate focal diffraction ring height is 1.2±0.04μm.

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