Intraocular lens

Abstract

The invention 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 controlling the material flicker value of the intraocular lens and adjusting the matching degree between the material refractive index and the diffraction perifocus additional focal power at the same time; therefore, the glare occurrence rate of the diffraction type multi-focus intraocular lens is greatly reduced, good far and near vision or far, middle and 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 present invention relates to the field of artificial lenses, and in particular to a multifocal artificial lens for treating cataracts, specifically a diffractive multifocal artificial lens. Background Art

[0002] Cataract is a common disease of the elderly and the number one killer of blindness worldwide. Surgery is the only effective way to treat cataracts. Modern cataract surgery involves implanting an artificial lens to replace the cloudy natural lens through phacoemulsification. After the natural lens of the cataract is removed, the human eye has other refractive needs in addition to the correction of refractive errors, such as correction of aberrations, astigmatism, and presbyopia. With the improvement of people's living standards and the development of technology, modern artificial lenses have appeared in a variety of design types, including aspheric lenses with aberration correction, Toric lenses with astigmatism correction, and multifocal lenses with presbyopia correction. Among them, correction of astigmatism and correction of presbyopia are both high-end refractive functions. High-end refractive functional intraocular lenses generally have high requirements for surgical operation and lens design, especially multifocal intraocular lenses. Due to their splitting mechanism and the addition of various non-smooth surfaces on the optical surface, this type of intraocular lens is often accompanied by inevitable glare problems, which affects the visual quality of patients after surgery. The probability of glare after surgery for existing multifocal intraocular lenses is as high as 50% or more, which requires patients to adapt for a long time and choose their own conditions, such as evaluating the patient's personality and tolerance in advance, before deciding whether to use it. Some patients even have to remove and replace the intraocular lens because they cannot adapt. Therefore, although multifocal intraocular lenses can solve the problem of presbyopia very well and even achieve full vision, adverse optical phenomena such as glare and halo seriously limit their use and promotion. How to improve the optical performance of high-end refractive intraocular lenses and reduce / reduce adverse optical phenomena after multifocal intraocular lenses is an important proposition generally faced by the industry.

[0003] In order to reduce adverse optical phenomena, existing multifocal intraocular lenses often make phase adjustments on the surface shape of the diffraction rings, such as Johnson & Johnson Vision Care's patent solution US11 / 259524, which uses a smooth structure on the diffraction surface to reduce glare; or Alcon's patent US12109107B2, which uses a diffraction ring height gradient structure to reduce glare interference; or the additional light focal length is made very small (such as Johnson & Johnson's Symfony, patent number US8,747,466B2), and the density of the diffraction ring is minimized to reduce glare. However, these measures have limited effects on the one hand, and on the other hand, the additional light focal length will affect the human eye's near vision ability. Sacrificing the additional light focal length to obtain better visual quality does not really solve the problem.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a multifocal intraocular lens that can reduce adverse optical phenomena, which can significantly reduce the glare incidence of diffraction multifocal intraocular lenses, obtain good far and near vision or full-range vision of far, medium and near after surgery, and improve the satisfaction with postoperative visual quality.

[0006] Specifically, the technical solution of the present invention is as follows: The present invention provides a multi-focal intraocular lens, the surface of which is provided with a diffraction structure for providing multiple focal points, and the material flare value of the intraocular lens is less than 100 MV / mm 2 ; and the material refractive index of the intraocular lens and the diffraction near focus additional power satisfy the following relationship: ; Wherein, n is the refractive index of the material, and ADD is the difference in optical power between the nearest focus and the far focus provided by the diffractive structure, that is, the additional optical power of the near focus.

[0007] The present invention creatively discovers the compensation mechanism of the chromatic aberration of the diffraction multifocal lens and the refractive chromatic aberration, and achieves the purpose of eliminating or reducing the chromatic aberration of the multifocal lens by adjusting the matching relationship between the two, and realizes achromatic aberration or even zero chromatic aberration. When the refractive index of the material is between 1.43 and 1.46, the focal length of the diffraction near focus additional light is between 1.0 and 3.2D; when the refractive index of the material is between 1.47 and 1.49, the focal length of the diffraction near focus additional light is between 2.0 and 4.2D; when the refractive index of the material is between 1.50 and 1.55, the focal length of the diffraction near focus additional light is between 3.6 and 6.3D. The multifocal intraocular lens designed with this matching relationship can greatly reduce the glare incidence of the diffraction multifocal intraocular lens.

[0008] Preferably, the material flare level of the intraocular lens at least satisfies ≤ level 1; wherein, when the flare of the intraocular lens is less than 50 MV / mm 2 , defined as level 0; when the flash is greater than 50MV / mm 2 ,<100MV / mm 2 , defined as level 1; when the flash is greater than 100MV / mm 2 ,<200MV / mm 2 When >200MV / mm 2 , defined as level 3. Material flare level ≤ level 1, preferably level 0, can reduce the glare of multifocal intraocular lenses.

[0009] Preferably, the refractive index of the material of the intraocular lens is between 1.46 and 1.48, and the diffraction near focus additional optical power is between 2.0 and 3.6 D. The intraocular lens in this preferred range is more suitable for making a multi-focal design.

[0010] Preferably, the intraocular lens is made of a hydrophobic acrylic material, does not contain a blue light absorber, and has a refractive index of 1.43-1.55 or 1.47-1.48.

[0011] Preferably, the water content of the material of the intraocular lens is ≤1%, preferably ≤0.5%.

[0012] The present invention uses a hydrophobic acrylate material without a blue light absorber, that is, without a blue light shield, which is more helpful to reduce the negative optical phenomena caused by the material.

[0013] Preferably, the diffraction structure is arranged on the rear surface of the intraocular lens. Compared with the front surface, placing the diffraction ring on the rear surface can further reduce the reflection and refraction of light by the diffraction surface and reduce stray glare.

[0014] Preferably, the diffraction structure is composed of a diffraction ring, which is located within a 5 mm diameter range of the center of the optical zone of the artificial lens, and more preferably within a 4.5 mm diameter range of the center of the optical zone of the artificial lens.

[0015] The present invention can further reduce the reflection and refraction of stray light by placing a diffraction structure (specifically, a diffraction ring) in a local area of ​​the rear surface of the optical part of the intraocular lens; in particular, by using a hydrophobic acrylic material that does not contain a blue light absorber, i.e., no anti-blue light shielding, and has a flare of ≤1 or even 0, 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 good far, medium and near vision can be obtained after surgery, while improving the satisfaction of postoperative visual quality.

[0016] As a more preferred embodiment, the refractive index of the material is 1.430±0.004, and the diffraction near focus additional optical power is between 1.8 and 2.6D. In this case, the artificial lens obtained has zero chromatic aberration.

[0017] As another more preferred embodiment, the refractive index of the material is 1.475±0.004, and the diffraction near focus additional optical power is between 2.5 and 3.4D. In this case, the artificial lens obtained has zero chromatic aberration.

[0018] As another more preferred embodiment, the refractive index of the material is 1.500±0.004, and the diffraction near focus additional optical power is between 3.8 and 4.6D. In this case, the artificial lens obtained has zero chromatic aberration.

[0019] Further preferably, in the present invention, the diffraction structure also has at least one of the following features (1) to (8): (1) The diffraction structure includes multiple sets of diffraction rings, wherein the interval between adjacent diffraction rings of the set with the largest distance is 0.16-0.66 mm, or 0.19-0.49 mm, or 0.22-0.40 mm; (2) The diffraction structure includes multiple sets of diffraction rings, among which the height of the set of diffraction rings with the largest distance is 0.77~3.51μm, or 0.77~3.33μm; (3) The diffractive structure provides two focal points, far and near; or provides three focal points, far, intermediate and near; or provides more than three focal points; (4) The spacing between adjacent focal points provided by the diffractive structure is ≥1.5D; (5) The light energy distribution ratio of the diffraction structure at the near focus is 30%~50% or 30%~40%; (6) The light energy distribution ratio of the diffraction structure at the far focus is 50%~60%; (7) The light energy distribution ratio of the diffraction structure at the central focus is 0%~20%; (8) The near focus additional optical power provided by the diffractive structure is 1~4D or 2.0~4.2D or 3.2D.

[0020] As a preferred embodiment, the artificial lens provided by the present invention is a trifocal artificial lens for far, intermediate and near focuses, and its material refractive index is 1.475±0.005; the additional optical power of the near focus is 4.2±0.04D, and the additional optical power of the intermediate focus is 2.1±0.04D; the height of the diffraction ring of the near focus is 2.3±0.04μm; and the height of the diffraction ring of the intermediate focus is 1.2±0.04μm.

[0021] As a more preferred embodiment, the artificial lens provided by the present invention is a trifocal artificial lens for far, intermediate and near focus, and its material refractive index is 1.475±0.005; the additional optical power of the near focus is 3.2±0.04D, and the additional optical power of the intermediate focus is 1.6±0.04D; the height of the diffraction ring of the near focus is 2.3±0.04μm; and the height of the diffraction ring of the intermediate focus is 1.2±0.04μm.

[0022] Preferably, the surface of the artificial lens is provided with any optical surface type of a toric surface, an aspherical surface, or a spherical surface.

[0023] Preferably, the artificial lens is made by turning.

[0024] Beneficial effects: The present invention provides a multifocal intraocular lens that can reduce adverse optical phenomena. By controlling the flare value of the material of the intraocular lens and adjusting the matching degree between the material refractive index and the diffraction near focus additional focal length at the same time, the glare incidence of the diffraction multifocal intraocular lens is achromatic or even zero chromatic aberration, thereby greatly reducing the glare incidence of the diffraction multifocal intraocular lens, obtaining good near and far vision or full-range near, far vision after surgery, and improving the visual quality satisfaction after surgery. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be described below.

[0026] Figure 1 This is a schematic diagram of excellent material color difference control.

[0027] Figure 2 Schematic diagram of acceptable material color difference limits.

[0028] Figure 3 Schematic diagram of the relationship between the refractive index of the material used to prepare the crystal and the degree of fit between the added optical power of the crystal. In the figure, cutoff: chromatic aberration can be perceived by the human eye; bell-shaped coverage area: does not exceed the resolution limit of the human eye, and the chromatic aberration caused by diffraction ≈ the chromatic aberration caused by refraction.

[0029] Figure 4 Schematic diagram of the MTF of the crystal under actual eccentricity when the diffraction rings are located on the front and back surfaces.

[0030] Figure 5 Schematic diagram of the PSF point spread function of the crystal at different resolutions when the diffraction rings are located on the front and back surfaces.

[0031] Figure 6 Schematic diagram of flare and its levels. In the figure, (a) is level 0; (b) is level 1; and (c) is level 2.

[0032] Figure 7 This is a schematic diagram comparing the contrast sensitivity of the two groups of subjects participating in the clinical trial 12 months after surgery.

[0033] Figure 8 This is a schematic diagram comparing the visual impairment symptoms of the two groups of subjects participating in the clinical trial 12 months after surgery.

[0034] Fig. 9 This is a schematic diagram of the structure of the trifocal intraocular lens described in Example 1.

[0035] Fig.10 This is a schematic diagram of the structure of the bifocal astigmatism correction intraocular lens described in Example 2. DETAILED DESCRIPTION

[0036] The preferred embodiments of the present invention will be described in detail below in conjunction with examples. It should be understood that the following examples are provided only for the purpose of illustration and are not intended to limit the scope of the present invention. Those skilled in the art may make various modifications and substitutions to the present invention without departing from the purpose and spirit of the present invention.

[0037] After a diffractive multifocal intraocular lens is implanted in the human eye, adverse visual phenomena may come from many sources, including: (1) optical interference between multiple focal points; (2) crystal chromatic aberration; (3) the diffraction surface is not smooth, and the incident light is refracted and reflected after passing through, causing messy light interference; (4) other defects in the material itself, such as flare. Among them, crystal chromatic aberration, flare and other phenomena also exist in ordinary single-focus lenses, but due to the diffractive multifocal light splitting mechanism, the light energy originally allocated to each focus is relatively small, and the optical quality is low, which will amplify various optical defects of the lens and cause adverse phenomena. Therefore, chromatic aberration and flare are often not perceived by patients after the implantation of ordinary single-focus lenses, but they often become the main complaints in multifocal lenses.

[0038] The present invention discovers the compensation mechanism of the chromatic aberration and refractive chromatic aberration of the diffraction multifocal lens, and obtains the matching relationship between the two, thereby achieving the purpose of eliminating or reducing the chromatic aberration of the multifocal crystal; by placing the diffraction ring (constituting the diffraction structure described in the present invention) in a local area of ​​the rear surface of the optical part of the artificial lens, the reflection and refraction of stray light are further reduced; by using a hydrophobic acrylic material that does not contain a blue light absorber, i.e., no anti-blue light shielding, and flare ≤1 level or even 0 flare, the negative optical phenomena caused by the material are reduced. Overall, the glare incidence of the diffraction multifocal artificial lens is greatly reduced, and while good far, medium and near vision is obtained after surgery, the satisfaction with the postoperative visual quality is improved.

[0039] The technical solution of the present invention is described in detail below in combination with theoretical analysis and specific embodiments.

[0040] (1) Compensation mechanism and matching relationship between diffraction multifocal chromatic aberration and refraction chromatic aberration

[0041] Chromatic aberration refers to the phenomenon that light of different wavelengths converges at different points after passing through an optical medium, resulting in a difference in optical path length. In multifocal intraocular lenses, it is a combination of two optical mechanisms, namely refraction and diffraction, so the source of chromatic aberration is divided into two parts. One part is the chromatic aberration caused by the material itself, called refraction chromatic aberration, and the other part is the chromatic aberration caused by the diffraction ring, called diffraction chromatic aberration.

[0042] The refractive chromatic aberration is related to the optical power. The optical power calculation method is shown in the following formula, where φ is the optical power, n' is the refractive index of the material used to make the artificial lens, 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.

[0043]

[0044] It can be seen that the convergence point is related to the refractive index of the light wave in the medium. 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. Color difference direction: red, orange, yellow, green, blue, indigo, and violet.

[0045] The focal length calculation method of diffraction is shown in the following formula, where f is the focal length, is the radius of the Nth ring; N is the number of diffraction rings, and λ is the wavelength.

[0046]

[0047] 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 focal length of the additional light. The higher the focal length of the additional light, the more serious the chromatic aberration.

[0048] Furthermore, we can know that the chromatic aberration of refraction is in the opposite direction to the chromatic aberration of diffraction, and the chromatic aberration of diffraction-type multifocal intraocular lenses can compensate each other. However, not all diffraction and refraction chromatic aberrations can compensate each other. They need to reach a level that is unrecognizable by the human eye in order to achieve "achromatism". The calculation method uses ray tracing. In Zemax, a human eye model is established according to the standard human eye. Intraocular lenses with different refractive indices are placed in the standard human eye model to calculate the residual chromatic aberration after combining different refractive indices with different additional optical powers. 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 compensated residual chromatic aberration is greater than the human eye resolution (about 10 wavelengths of the retina), the chromatic aberration can be perceived by the human eye as a color difference and is considered unacceptable; when the defocus caused by the compensated residual chromatic aberration is less than the human eye resolution, it is considered "achromatic", at which time the diffraction additional light power matches the refractive index better; when the defocus caused by the compensated residual chromatic aberration is 0, it is considered "0 chromatic aberration", at which time the diffraction design and the refractive design match best. Figure 1 and Figure 2 shown.

[0049] The present invention creatively concludes that when the refractive index of the preparation material of the artificial lens is between 1.43 and 1.46, the near focus additional light focal length is between 1.0 and 3.2D, which can achieve achromatism. Further, when the refractive index is 1.43, the near focus additional light focal length is between 1.8 and 2.6D, then the degree of chromatic aberration compensation is better, and the result of almost 0 chromatic aberration is achieved. When the refractive index of the material is between 1.47 and 1.49, the near focus additional light focal length is between 2.0 and 4.2D, which can achieve achromatism. Further, when the refractive index is 1.475, the near focus additional light focal length is between 2.5 and 3.4D, then the degree of chromatic aberration compensation is better, and the result of almost 0 chromatic aberration is achieved. When the refractive index of the material is between 1.50 and 1.55, the near focus additional power is between 3.6 and 6.3D, which can achieve achromatism. Furthermore, when the refractive index is 1.50, the near focus additional power is between 3.8 and 4.6D, and the degree of chromatic aberration compensation is better, almost reaching 0 chromatic aberration. In summary, it can be concluded that the near focus additional power provided by the diffractive structure matches the refractive index of the material used to prepare the intraocular lens, and the two satisfy the following relationship: .

[0050] Wherein, n is the refractive index of the material used to prepare the intraocular lens, and ADD is the difference in optical power between the nearest focus and the far focus provided by the diffraction structure (the diffraction ring in the present invention) of the multifocal intraocular lens, that is, the additional optical power of the near focus.

[0051] The near focus of a multifocal intraocular lens is related to the near vision ability. The higher the additional optical power, the stronger the near vision ability and the closer the near vision distance. At present, the near vision ability requirement of the human eye is generally between 2D and 3.6D. Therefore, when the refractive index of the lens material is between 1.46 and 1.48, it is more suitable for making a multifocal design. Figure 3 As shown, the crystal material has a high refractive index and the material chromatic aberration is the most difficult to balance, requiring extremely high additional optical power, which usually manifests as excess refractive chromatic aberration.

[0052] (2) Diffraction ring placement and distribution

[0053] The diffraction structure set on the surface of the optical part of the artificial lens is a non-smooth structure with a stepped property. When light is incident on the artificial lens, the inclined surface of the diffraction step structure itself will reflect the light to various angles. At the same time, when the light passes through the diffraction ring, it will also cause messy refracted light. These are the sources of glare caused by stray light of multifocal lenses.

[0054] The diffraction ring structure is placed on the front and back surfaces of the lens, and the degree of harm caused by stray light is different. The present invention uses ZEMAX simulation and ray tracing to simulate and conduct in-depth research. For example, two multifocal intraocular lenses are designed, and the material, refractive power, center thickness, optical zone size, and additional optical power of the intraocular lenses are the same, wherein the crystal refractive index is 1.475, the optical zone diameter is 6.0mm, the center thickness is 0.8mm, the refractive power is +20.0D, the dual-focus design, the additional optical power is 3.2D, the diffraction ring height is 1.72μm, and a light energy distribution of far:near=60:40 is provided. The only difference between the two crystals is that the diffraction ring of one is located on the front surface of the optical zone of the crystal, and the diffraction ring of the other is located on the back surface of the optical zone of the crystal. The crystal was placed in the standard human eye model, and the MTF and PSF point spread functions of the crystal were observed under actual eccentricity and different resolutions. It was found that when the diffraction ring of the crystal was located on the back surface, the MTF was higher at all resolutions under eccentricity conditions, and the PSF point spread function was more ideal. Figure 4 and Figure 5 shown.

[0055] It can be seen that compared with the diffraction ring set on the front surface of the lens, the diffraction ring of the diffraction-type multifocal intraocular lens is located on the back surface of the intraocular lens, which can reduce the reflection and refraction of light by the diffraction surface, reduce stray glare, and help improve optical performance.

[0056] (3) Material properties

[0057] Flare is a common problem of hydrophobic acrylates. During the material synthesis process, the gaps between the molecules of the material are caused by the process. When the gaps reach a certain number and volume, the crystal will appear like "starlight" under lighting conditions, which is called "flare" in the industry. According to international testing methods, when the flare of the intraocular lens is less than 50MV / mm 2 , defined as level 0; when the flash is greater than 50MV / mm 2 ,<100MV / mm 2 , defined as level 1 flare; when flare > 100MV / mm 2 ,<200MV / mm 2 When >200MV / mm, it is defined as Level 2 flash; when >200MV / mm 2 , defined as level 3 flare. Figure 6As shown, (a), (b), and (c) are the states of close to zero flare (level 0), good flare control (level 1), and large flare (level 2), respectively. The flare phenomenon is common in the field of intraocular lenses. When materials with flare are used in monofocal intraocular lenses, the human eye is not very sensitive to it because the lens itself can achieve a high resolution. Therefore, this phenomenon is generally only observed by doctors under slit lamps after surgery, and most patients have no personal experience or clinical complaints. However, due to the splitting mechanism of multifocal intraocular lenses, the optical resolution (MTF) decreases by 60% or more. The presence of flare will be enhanced by the multifocal mechanism, thereby affecting the patient's visual quality. For example, in clinical practice, Alcon's lens has a high refractive index of 1.55 and is molded. The material itself has a low flare level. The flare research test results of its material Acrysof material (SN60WF) are 61 ± 33 MVs / mm 2 , can only reach level 2 and above. When applied to multifocal lenses, more glare is often observed. Therefore, the present invention proposes that when manufacturing multifocal intraocular lenses, the flare level should be ≤ level 1, preferably level 0 (≤1.8±0.9 MV / mm 2 ) for production.

[0058] Furthermore, the molding of artificial lenses is divided into a molding process and a turning process. The molding process is to directly inject the monomer into the mold and then directly mold the artificial lens. This process is more likely to allow moisture and air to enter the mold during synthesis, causing more flare. The present invention preferably uses a turning process to first make large blocks of material and then turn the material into small artificial lenses. This process is more stable in synthesis, and the material is more uniform inside, and air and moisture are not easy to enter, so the flare phenomenon is less, which is more suitable for making multifocal artificial lenses.

[0059] In addition, although the hydrophobic acrylate material is called hydrophobic, it also has a certain water content. In the industry, generally, a hydrophobic material is one with a water content of less than 1%. If the hydrophobic material maintains a certain water content, then after the lens is implanted, the gaps in the lens that form flare will be filled with the water content of the lens, thereby eliminating the flare. Therefore, the appropriate water content of the hydrophobic material can also eliminate the flare, but the increase in water content will cause problems in power drift, storage, sterilization, etc. Therefore, the multifocal intraocular lens of the present invention is preferably made of hydrophobic acrylate with a water content of ≤0.5%.

[0060] In addition, when the height / width of the diffraction ring of the artificial lens provided by the present invention matches the refractive index of the material, a better achromatic effect can be achieved.

[0061] In summary, the present invention proposes that, when manufacturing a multifocal intraocular lens, a flare level of ≤1 is used, preferably, a flare level of 0 (≤1.8±0.9 MV / mm2 ) for production; and / or, using hydrophobic acrylate with a water content of ≤1%, preferably, a water content of ≤0.5% to produce an intraocular lens; and / or, using a turning process to process an intraocular lens, which can significantly eliminate flare and thereby reduce the glare of a multifocal intraocular lens.

[0062] like Figure 7 and Figure 8 As shown, the implementation scheme of the present invention was used to observe adverse visual phenomena such as glare and halo in patients after surgery in clinical trials, and it was found that compared with the current existing technologies in the industry, it is significantly superior in terms of contrast sensitivity, glare, adverse visual symptoms, and postoperative satisfaction.

[0063] in, Figure 7 Comparison of sensitivity between the two groups of subjects 12 months after surgery (left: dark light; right: dark light glare; ns means no statistically significant difference, * means p <0.05). Four background lights were set in the experiment, namely bright light (85cd / m 2 )、Bright light glare(135Lux)、Dark light(3cd / m 2 ), dark light glare (28Lux); set 5 spatial frequencies, namely 1.5c / d, 3.0c / d, 6.0c / d, 12.0c / d, and 18.0c / d. The experimental results showed that 12 months after surgery, the dark light condition 6.0c / d test group was significantly higher than the control group ( p <0.05), there was no statistical difference between the groups under other background light conditions and spatial frequencies ( p >0.05).

[0064] Figure 8 Comparison of poor visual symptoms between the two groups of subjects 12 months after surgery (ns means no statistically significant difference, * means p <0.05). Experimental evaluation method: Five kinds of visual impairment phenomena (halo, glare, blurred vision, ghosting, diplopia) were graded into five levels (none, mild, mild, moderate, severe). The experimental results showed that 12 months after surgery, the degree of glare in the experimental group was significantly lower than that in the control group ( p <0.05), there were no statistically significant differences in other visual impairment symptom evaluation indicators between the groups ( p >0.05).

[0065] Example 1

[0066] This embodiment provides a trifocal intraocular lens.

[0067] The trifocal intraocular lens provided in this embodiment is made of hydrophobic acrylic, with a refractive index of 1.475 and a water content of <0.5%. It is formed by a turning process, with a main body of the lens having a diopter of +20.0D, an optical zone diameter of 6.0mm, a conventional aspheric surface on the front surface, and a diffraction ring within the 4.5mm optical zone diameter of the rear surface. 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: far, middle, and near. The near focus additional focal power (ADD) is 4.2D, consisting of 11 rings at odd intervals of 1, 3, 5…21, with a ring height of 2.3μm, and 30% of the light energy is allocated to the near focus; the middle focus additional focal power (ADD) is 2.1D, consisting of 11 rings at intervals of 2, 4, 6…22, with a ring height of 1.2μm, and 20% of the light energy is allocated to the middle focus. Finally, the far focus obtains 50% of the light energy. The parameters of the diffraction rings are shown in Table 1. Crystal structure Fig. 9 .

[0068]

[0069] Through ZEMAX simulation, it can be seen that the near focus additional light power of the trifocal diffractive intraocular lens is well matched with the material refractive index, and the residual chromatic aberration formed by the far focus additional light power and the material refractive index in the human eye is 2.53 wavelengths, which is close to 0 chromatic aberration, and the achromatic effect is good.

[0070] In this embodiment, the diffraction ring of the crystal does not occupy the entire area of ​​the optical part. Within the diameter range of 4.5mm, the focus is mainly far vision, supplemented by near focus, and the intermediate focus accounts for the lowest proportion. The reason is that the additional focal length of the intermediate focus is generally matched with the refractive index of the material. In order to prevent the introduction of more chromatic aberration, its light energy proportion is reduced. Within the range of 4.5-6.0mm, the energy is mainly distributed in the far focus, and the energy distribution ratio of the far focus increases, ensuring good far vision under dark light conditions and reducing glare.

[0071] In this embodiment, the far focus diopter of the intraocular lens can be between -10 and +40 D, preferably, -10 to +36 D, and more preferably, 5 to 30 D. At the same time, the trifocal design can also be combined with other optical designs, such as using an astigmatism complex surface design and an EDF aspheric surface design on the front surface to correct human eye astigmatism while providing far, middle and near focus.

[0072] In the same way as in the present embodiment, it can be imagined that when the hydrophobic acrylic ester with the refractive index is used to make this type of crystal, the near-focus additional optical power of the crystal can be between 2.5 and 3.4D, which can achieve a good chromatic aberration compensation. When other materials are used to make similar trifocal crystals, the chromatic aberration compensation of the near focus is also used as the design limit. When the material refractive index is between 1.43 and 1.46, the near focus additional optical power is between 1.0 and 3.2D; when the material refractive index is between 1.47 and 1.49, the near focus additional optical power is between 2.0 and 4.2D; when the material refractive index is between 1.50 and 1.55, the near focus additional optical power is between 4 and 6.3D.

[0073] Example 2

[0074] This embodiment provides a bifocal astigmatism-correcting intraocular lens.

[0075] The intraocular lens described in this embodiment is made of hydrophobic acrylic, with a refractive index of 1.48 and a water content of <0.5%. It is formed by a turning process, with a main body of the lens having a diopter of +20.0D, an optical zone diameter of 6.0mm, a complex surface on the front surface, and an astigmatism axis mark. The surface equation of the complex surface is: .

[0076] Where c1 is the curvature of the rotation axis, c2 is the generatrix curvature. The optical surface of the intraocular lens is the XY plane, and z is the axial thickness direction. The crystal cylinder power is 1.5D, the curvature radius of the main mirror direction is 18.459mm, and the curvature radius of the cylindrical direction is 15.548mm.

[0077] The back surface has a diffraction ring within the 4.0mm optical zone diameter, and the diffraction area accounts for 66.7% of the total optical area. There are 9 diffraction rings in total, providing two focal points, far and near. The additional focal power (ADD) of the near focus is 3.2D, and the ring height is 1.78μm. 40% of the light energy is distributed to the near focus, and the far focus obtains 60% of the light energy. The diffraction ring parameters are shown in Table 2. The crystal structure is shown in Fig.10 .

[0078]

[0079] Through ZEMAX simulation, it can be known that the near-focus additional optical power of the bifocal diffractive intraocular lens is well matched with the material refractive index, and the residual chromatic aberration formed by the additional optical power and the material refractive index in the human eye is 0.6 wavelengths, and the achromatic effect is good.

[0080] In this embodiment, the diffraction ring of the crystal does not occupy the entire area of ​​the optical part, and within the diameter range of 4.0 mm, it is slightly focused on far vision. Within the range of 4.0-6.0 mm, the energy is mainly distributed at the far focus, and the energy distribution ratio of the far focus is increased, ensuring good far vision under dark light conditions and reducing glare.

[0081] In this embodiment, the far focus diopter of the intraocular lens may be between -10 and +40D, preferably, between -10 and +36D, and more preferably, between 5 and 30D.

[0082] In the same way as in the present embodiment, it can be imagined that when the hydrophobic acrylate of the refractive index is used to make this type of crystal, the near-focus additional focal length of the crystal can be between 2.0 and 4.2D, and a good degree of chromatic aberration compensation can be achieved, especially when the additional focal length is between 2.6 and 3.5D, close to 0 chromatic aberration. When other materials are used to make similar trifocal crystals, the degree of chromatic aberration compensation of the near focus is also used as the limit of the design. When the material refractive index is between 1.43 and 1.46, the near focus additional focal length is between 1.0 and 3.2D; when the material refractive index is between 1.47 and 1.49, the near focus additional focal length is between 2.0 and 4.2D; when the material refractive index is between 1.50 and 1.55, the near focus additional focal length is between 3.6 and 6.3D.

[0083] Example 3

[0084] This embodiment provides a bifocal intraocular lens.

[0085] The intraocular lens described in this embodiment is made of hydrophobic acrylic, with a refractive index of 1.50 and a water content of <0.5%. It is formed by a turning process, with a main body of the lens having a diopter of +15.0D, an optical zone diameter of 6.0mm, a spherical front surface, and a diffraction ring within the 4.0mm optical zone diameter of the rear surface. The diffraction area accounts for 66.7% of the total optical area. There are 20 diffraction rings in total, providing two focal points, far and near. The additional focal power (ADD) of the near focus is 3.6D, and the ring height is 1.68μm, which distributes 50% of the light energy to the near focus. The parameters of the diffraction rings are shown in Table 3.

[0086]

[0087] Through ZEMAX simulation, it can be known that the near-focus additional optical power of the bifocal diffractive intraocular lens is well matched with the material refractive index, and 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.

[0088] In this embodiment, the diffraction ring of the crystal does not occupy the entire area of ​​the optical part, and within the diameter range of 4.0 mm, it is slightly focused on far vision. Within the range of 4.0-6.0 mm, the energy is mainly distributed at the far focus, and the energy distribution ratio of the far focus is increased, ensuring good far vision under dark light conditions and reducing glare.

[0089] In this embodiment, the far focus diopter of the intraocular lens may be between -10 and +40D, preferably, between -10 and +36D, and more preferably, between 5 and 30D.

[0090] With the same idea as the present embodiment, it can be imagined that when this type of crystal is made using hydrophobic acrylate with this refractive index, the close-range additional optical focal length of the crystal can be between 2.4 and 4.6D, which can achieve a good degree of chromatic aberration compensation, especially when the additional optical focal length is between 2.8 and 3.6D, close to 0 chromatic aberration.

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An artificial lens having a diffraction structure on its surface for providing multiple focal points, characterized in that: The material flare value of the intraocular lens is less than 100MV / mm 2 ; and the material refractive index of the intraocular lens and the diffraction near focus additional power satisfy the following relationship: ； Wherein, n is the refractive index of the material, and ADD is the difference in optical power between the nearest focus and the far focus provided by the diffractive structure, that is, the additional optical power of the near focus.

2. The intraocular lens according to claim 1, characterized in that: The material flare level of the intraocular lens at least meets ≤ level 1, preferably level 0; wherein, when the flare of the intraocular lens is less than 50 MV / mm 2 , defined as level 0; when the flash is greater than 50MV / mm 2 ,<100MV / mm 2 , defined as level 1; when the flash is greater than 100MV / mm 2 ,<200MV / mm 2 When >200MV / mm 2 , defined as level 3.

3. The intraocular lens according to claim 1 or 2, characterized in that: The refractive index of the material of the artificial lens is between 1.46 and 1.48, and the diffraction near focus additional light power is between 2.0 and 3.6D.

4. The intraocular lens according to any one of claims 1 to 3, characterized in that: The artificial lens is made of hydrophobic acrylic material, does not contain blue light absorber, and the refractive index of the material is 1.43~1.55 or 1.47~1.

48.

5. The intraocular lens according to any one of claims 1 to 4, characterized in that: The water content of the material of the intraocular lens is ≤1%, preferably ≤0.5%.

6. The intraocular lens according to any one of claims 1 to 5, characterized in that: The diffractive structure is disposed on the rear surface of the intraocular lens.

7. The intraocular lens according to any one of claims 1 to 6, characterized in that: The diffraction structure is composed of diffraction rings, which are located within a 5 mm diameter range of the center of the optical zone of the artificial lens, and more preferably within a 4.5 mm diameter range of the center of the optical zone of the artificial lens.

8. The intraocular lens according to any one of claims 1 to 7, characterized in that: The material refractive index is 1.430±0.004, the diffraction near focus additional power is between 1.8~2.6D, and there is no chromatic aberration; Alternatively, the material refractive index is 1.475±0.004, the diffraction near focus additional power is between 2.5 and 3.4D, and there is 0 chromatic aberration; Alternatively, the material refractive index is 1.500±0.004, the diffraction near focus additional power is between 3.8 and 4.6D, and there is 0 chromatic aberration.

9. The intraocular lens according to any one of claims 1 to 8, characterized in that: The diffraction structure also has at least one of the following features (1) to (8): (1) The diffraction structure includes multiple sets of diffraction rings, wherein the interval between adjacent diffraction rings of the set with the largest distance is 0.16-0.66 mm, or 0.19-0.49 mm, or 0.22-0.40 mm; (2) The diffraction structure includes multiple sets of diffraction rings, among which the height of the set of diffraction rings with the largest distance is 0.77~3.51μm, or 0.77~3.33μm; (3) The diffractive structure provides two focal points, far and near; or, provides three focal points, far, intermediate, and near; Alternatively, more than 3 focal points are provided; (4) The spacing between adjacent focal points provided by the diffractive structure is ≥1.5D; (5) The light energy distribution ratio of the diffraction structure at the near focus is 30%~50% or 30%~40%; (6) The light energy distribution ratio of the diffraction structure at the far focus is 50%~60%; (7) The light energy distribution ratio of the diffraction structure at the central focus is 0%~20%; (8) The near focus additional optical power provided by the diffractive structure is 1~4D or 2.0~4.2D or 3.2D.

10. The intraocular lens according to any one of claims 1 to 9, characterized in that: The intraocular lens is a trifocal intraocular lens with far, intermediate and near focal lengths, and the material refractive index is 1.475±0.005; the near focus additional optical power is 4.2±0.04D, and the intermediate focus additional optical power is 2.1±0.04D; the near focus diffraction ring height is 2.3±0.04μm; and the intermediate focus diffraction ring height is 1.2±0.04μm; Alternatively, the intraocular lens is a trifocal intraocular lens of far, intermediate and near focus, and its material refractive index is 1.475±0.005; the near focus additional optical power is 3.2±0.04D, and the intermediate focus additional optical power is 1.6±0.04D; the near focus diffraction ring height is 2.3±0.04μm; and the intermediate focus diffraction ring height is 1.2±0.04μm.

11. The intraocular lens according to any one of claims 1 to 10, characterized in that: The surface of the artificial lens is provided with any optical surface type of a toric surface, an aspherical surface, or a spherical surface.

12. The intraocular lens according to any one of claims 1 to 11, characterized in that: The artificial lens is made by a turning process.

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