Wavefront-regulated continuous-visual-range artificial lens

Abstract

The invention provides a wavefront regulated continuous visual range intraocular lens, the wavefront aberration of the intraocular lens is deeply regulated through a Zernike polynomial, the wavefront distribution is regulated by controlling the aberration of different areas on the optical surface of the intraocular lens, so that the focus is not focused on a certain point in a concentrated manner any more, and the focal length of the intraocular lens is adjusted. The lenses are distributed in a certain focal depth range (1.5 D to 3.5 D), so that the depth of field is prolonged, continuous and seamless switching vision from far to near is provided, and focus switching among different distances is not needed. Through Zernike wavefront regulation and control, connection between focuses is smoother, no fixed focus exists, the full-continuous visual range is provided, meanwhile, the light energy utilization rate is high, and therefore a patient can obtain high dark vision after an operation.

Description

Technical Field

[0001] The present application relates to an artificial lens in the field of medical devices, and in particular to a wavefront-controlled continuous-range artificial lens. Background Art

[0002] An artificial lens is an implantable medical device made of polymer materials. It is used to replace the aging natural lens of the human eye and is placed in the anterior or posterior chamber of the eye to treat cataracts or refractive errors.

[0003] The optical design of multifocal intraocular lenses is generally divided into diffraction type and refractive type. They focus the optics into multiple concentrated focal points in different ways, which can increase the distance that the patient can see clearly to a certain extent. However, due to the high concentration of light at different focal points, glare, halo or starburst phenomena occur at night or in dark light environments, affecting visual comfort. At the same time, since multifocal intraocular lenses provide at least two or more focal points, it may be difficult for the brain to adapt to the focus switching, resulting in visual confusion or blur. For example, the patent publication No. CN110062899A entitled Intraocular Lens with Zone-by-Zone Step Height Control constructs the Fresnel zone by manufacturing a sawtooth optical step structure on the front or back surface of the lens. When parallel light is incident on the human eye and passes through the Fresnel zone, it is diffracted and focused on several different diffraction orders. Different diffraction orders have different refractive powers and different light energy distribution ratios. At the same time, a large part of the light will be diffracted to useless focal points, forming stray light, causing visual impact, so low light energy utilization is also a major problem of diffraction-type intraocular lenses.

[0004] All of the above reasons have caused many difficulties in the clinical use of multifocal intraocular lenses, so the intraocular lenses with extended depth of field were born. However, there are also several common problems with the existing intraocular lenses with extended depth of field. For example, the patent publication with publication number CN104755012A entitled Multi-ring lens, system and method for extending focal depth adopts Echelette diffraction grating technology. Through a special diffraction grating design, the light is dispersed to different focal points, extending the depth of field, so that patients can obtain clear vision at different distances. It adopts two small steps of diffraction steps to design a small additional light focal diffraction crystal, and the depth of field of the human eye can achieve the effect of delayed depth of field. However, it is still based on diffraction technology, and the problem of stray light cannot be avoided, and the light energy utilization rate is less than 85%. For example, the patent publication number CN115778631A entitled Ophthalmic Lens adjusts the concentration of the main focus by adjusting the high-order coefficient of the aspheric surface to diffuse the light spot and achieve the effect of extending the depth of field. However, the depth of field obtained by adjusting the aspheric coefficient alone is very limited, and the range of its focal depth is relatively small, making it difficult to achieve the effect of continuous visual range. The patent publication number CN 110711050 A entitled An Artificial Lens uses Zernike polynomials to characterize the optical surface to improve the technology of traditional aspheric intraocular lenses and astigmatism intraocular lenses. One of the surfaces is used as an asymmetric structure, which can reduce the aberration caused by part of the cornea and achieve a better effect of far vision to a certain extent, but it cannot achieve continuous visual range, and good vision cannot be obtained at medium and close distances, and the continuity of visual range is also lost. Summary of the invention

[0005] The present invention aims at the problem of discontinuous visual range of artificial lenses in the prior art, and provides an artificial lens. The wavefront aberration of the artificial lens is adjusted by using Zernike polynomials in different regions. The aberration of different regions on the optical surface of the artificial lens is controlled to adjust the distribution of the wavefront, so that the focus is no longer concentrated on a certain point, but is continuously distributed within a certain focal depth (1.5D to 3.5D), so as to extend the depth of field and provide continuous and seamless switching of vision from far to near, without switching the focus between different distances. The specific technical solution is as follows:

[0006] An intraocular lens that achieves extended depth of field through wavefront regulation, the intraocular lens comprising an optical part and a mechanical part, one surface of the optical part is set as a free-form surface formed by Zernike wavefront regulation, and the corresponding other surface is a spherical surface or an aspherical surface; the mechanical part is a support haptic;

[0007] The free-form surface is divided into two or more continuous regions from the center outwards, and the aberration type of each region is selected and set according to the Zernike polynomial to determine the aberration value. , the adjacent areas are set to different types of aberrations; the relationship between the surface curve of the free-form surface in polar coordinates is as follows:

[0008] (1)

[0009] in, is the working wavelength, n2 is the refractive index of the intraocular lens, n1 is the refractive index of the aqueous humor, is the polar coordinate form of the wavefront function of the intraocular lens surface, Through adjustment and derivation of formula (2)-(4),

[0010] (2)

[0011] (3)

[0012] (4)

[0013] Where: n is the radial order (n ≥ 0), m is the angular frequency (|m|≤n, and n−|m| is an even number), ρ is the normalized radial coordinate (0≤ρ≤1), and θ is the angular coordinate (0≤θ<2π); is the adjustment coefficient, which indicates the weight of the corresponding aberration, ranging from -5 to 10; k is the integer index variable in the summation formula, which starts from 0 and gradually increases until it reaches the upper limit .

[0014] The polar coordinate relationship (1) of the present invention can be expressed by r=r 0 , Zf(r)= r 0 , which is converted into the Cartesian coordinate system relationship between the free surface vector height Zf(r) and the radial coordinate r on the optical axis from the center point of the lens.

[0015] Furthermore, the support loop is an L-shaped, C-shaped or plate-shaped loop.

[0016] Furthermore, the free-form surface has a diameter range of 5.5 mm to 7.5 mm, and is divided into 2 to 5 regions from the center outward, with the diameter of each region increasing by 1 to 1.5 mm.

[0017] Furthermore, the Zernike polynomials can be selected to be of 0-multiple orders, and the aberration types in each region are translation, defocus, astigmatism, spherical aberration, tilt or coma, etc.

[0018] Furthermore, the optical surface shape of the aspheric surface is expressed as follows:

[0019] (5)

[0020] Among them, Z(r) is the aspheric surface function, r is the radial coordinate, the distance from the center point of the lens on the optical axis, R is the curvature radius of the basic sphere, K is the quadratic surface coefficient, is the coefficient of the aspheric high-order term, i=1,2,…,n, n is a natural number not less than 1; when K=0, and the coefficient of the aspheric high-order term When both are 0, the surface is a sphere.

[0021] Among them, the present invention can use 0-multi-order Zernike polynomials. The following table 1 symbolically lists the first 4 orders, and the corresponding wavefront diagram of the concentrated aberration mode is as follows: Figure 1 shown.

[0022] Table 1

[0023]

[0024] The present invention adjusts the corresponding weights of different aberrations and obtains the adjusted optical surface according to formulas (2) to (4). When confirming the specific adjustment, computer calculation is performed to confirm the setting ratio of different types of aberration weights with reference to the focus situation after ray tracing. The lens is placed in a theoretical eye model, and after modifying the aberration weights of different areas, optimization and adjustment are performed in real time until the optimal solution is obtained, which is the best weight value that extends the focus without generating breakpoints.

[0025] The advantages of the artificial lens of the present invention that performs wavefront regulation by using Zernike polynomials in different regions are: no stray light can be achieved, light energy utilization rate is 100%, all incident light rays will become part of the effective focus, thereby avoiding glare and other phenomena; Zernike polynomials have a high degree of adjustment for the wavefront, avoiding restrictions between regions, freely controlling the aberrations in different regions, directly controlling the imaging result, and then converting it into a sagittal height processing surface type of a free-form surface, thereby realizing the formation of a highly liberalized free-form surface on the optical surface of the artificial lens, and achieving a higher depth of field range compared to high-order aspheric surfaces; Zernike wavefront regulation, by controlling the adjustment coefficients of different regions, makes the connection between the focus and the focus smoother, without a fixed focus, and compared to the focus formed by diffraction, it will not be concentrated and has useless diffraction orders, thereby avoiding the formation of stray light, thereby reducing visual interference; since a full continuous visual range is provided while light energy utilization rate is high, patients can obtain higher dark vision after surgery. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is the wavefront diagram of the concentrated aberration mode;

[0027] Figure 2 This is a schematic diagram of the structure of an artificial lens;

[0028] Figure 3is the wavefront curve of the free-form surface in Example 1;

[0029] Figure 4 This is a schematic diagram of the arrow height distribution in Example 1;

[0030] Figure 5 A comparison diagram of the intraocular lens of Example 1 and monofocal and multifocal intraocular lenses in the prior art;

[0031] Figure 6 is the wavefront curve of the free-form surface in Example 2;

[0032] Figure 7 This is a schematic diagram of the arrow height distribution in Example 2;

[0033] Figure 8 This is a comparison chart of the intraocular lens of Example 2 and the monofocal and multifocal intraocular lenses in the prior art. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] Example 1

[0036] In this embodiment, the structure of the intraocular lens is as follows: Figure 2 As shown, the diameter of the optical part of the free-form surface is 6 mm, and the free-form surface is divided into 4 areas, wherein the first area is adjusted to zero aberration by Zernike polynomials to achieve good far vision; the second area is adjusted to positive spherical aberration by Zernike polynomials for the surface range, and its weight is set to 0.42, so that the far vision is shifted to the middle distance, but by setting the aberration coefficient, the formation of visual breakpoints is avoided, and the depth of focus is continuous; the third area increases the defocus aberration while increasing the negative spherical aberration, and its weight distribution is set to 0.27 and -0.09, so that the vision is shifted to the near distance and is continuous with the middle vision, so that a continuous visual range at three visual distances of far, middle and near can be formed; the fourth area is set to the zero aberration area to enhance the vision in dark environments; the wavefront curve of the free-form surface set in this way is shown as follows Figure 3 As shown, after the basic optical power is introduced, the wavefront transformed sagittal height distribution is added to the Cartesian coordinate system, and the sagittal height distribution of this embodiment is as follows: Figure 4 shown.

[0037] The other surface in this embodiment is set as a high-order aspheric surface. The detailed setting parameters of the two different optical surfaces are shown in Tables 2 and 3 below. This allows patients implanted with the artificial lens to see clearly at near, far, and far at the same time, and greatly reduces visual interference; this embodiment is placed in the model eye required by "ISO 11979-2:2024 5th Edition Ophthalmic Implants - Artificial Lenses" to test its modulation transfer function (MTF) response curve with defocus, and compared with the monofocal and multifocal artificial lenses of the prior art, the results are as follows Figure 5 As shown, in its MTF response curve with defocus, the MTF value will not be continuously lower than 0.1, and the focal depth range where the MTF is greater than 0.1 is greater than 2.5D, and the visual range continuity is good, and its visual range continuity is much better than the existing technology.

[0038] Table 2:

[0039]

[0040] Table 3:

[0041]

[0042] Example 2

[0043] In this embodiment, the diameter of the optical part of the free-form surface is 6.5 mm, and the free-form surface is divided into three areas. In the first area, the positive spherical aberration is adjusted by the Zernike polynomial to directly shift the far focus to the middle distance, and the weight distribution is set to 0.33; in the second area, the defocus aberration is set to the surface by the Zernike polynomial while the negative spherical aberration is added to set the near focus, and the weight distribution is set to 0.56 and -0.12; the third area is set to an area where the spherical aberration gradually increases with the radial distance, and its weight value is 0.11r (r is the radial distance from the surface to the center), which enhances the vision in dark environments and increases the continuity between near vision and intermediate vision. The wavefront curve of the free-form surface set in this way is shown in FIG. Figure 6 As shown, after the basic optical power is introduced, a few drops of wavefront conversion sagittal height distribution are added, and the sagittal height distribution of this embodiment is as follows Figure 7 shown.

[0044] The other surface in this embodiment is set as a high-order aspheric surface. The detailed setting parameters of the two different optical surfaces are shown in the following table. At this time, the surface shape of the front and back surfaces of the intraocular lens of the embodiment of the present invention is obtained. The present embodiment is placed in the model eye required by "ISO11979-2:2024 5th Edition Ophthalmic Implants - Intraocular Lenses" to test its modulation transfer function (MTF) response curve with defocus, and compared with the monofocal and multifocal intraocular lenses of the prior art. The results are as follows: Figure 8As shown in the figure, in the response curve of MTF with defocus, the MTF value will not be lower than 0.1 continuously, and the focal depth range where MTF is greater than 0.1 is greater than 3D, and the visual range continuity is good. It can be seen that the continuity of its visual range is much better than the existing technology, and it has good vision at various viewing distances, achieving the effect of full visual range continuity.

[0045] Table 4:

[0046]

[0047] Table 5:

[0048]

[0049] The above describes in detail the preferred implementation of this patent, but this patent is not limited to the above implementation. Various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of this patent.

Claims

1. A wavefront-controlled continuous-range intraocular lens, characterized in that: The intraocular lens comprises an optical part and a mechanical part, wherein one surface of the optical part is set as a free-form surface formed by Zernike wavefront regulation, and the corresponding other surface is a spherical surface or an aspherical surface; the mechanical part is a support haptic; The free-form surface is divided into two or more continuous regions from the center outwards, and the aberration type of each region is selected and set according to the Zernike polynomial to determine the aberration value. , the adjacent areas are set to different types of aberrations; the relationship between the surface curve of the free-form surface in polar coordinates is as follows: （1） in, is the working wavelength, n2 is the refractive index of the intraocular lens, n1 is the refractive index of the aqueous humor, is the polar coordinate form of the wavefront function of the intraocular lens surface, Adjust and deduce through equations (2)-(4); （2） （3） (4) Where: n is the radial order, n ≥ 0; m is the angular frequency, |m|≤n, and n−|m| is an even number; ρ is the normalized radial coordinate, 0≤ρ≤1; θ is the angular coordinate, 0≤θ<2π; is the adjustment coefficient, which indicates the weight of the corresponding aberration, ranging from -5 to 10; k is the integer index variable in the summation formula, which starts from 0 and gradually increases until it reaches the upper limit .

2. A wavefront-controlled continuous-range intraocular lens according to claim 1, characterized in that: The support loop is L-shaped, C-shaped or plate-shaped.

3. The wavefront-controlled continuous-range intraocular lens according to claim 1, characterized in that: The free-form surface has a diameter range of 5.5 mm to 7.5 mm and is divided into 2 to 5 regions from the center outwards, with the diameter of each region increasing by 1 to 1.5 mm.

4. The wavefront-controlled continuous-range intraocular lens according to claim 1, characterized in that: The Zernike polynomials use 0-multiple orders, and the aberration types in each region are translation, defocus, astigmatism, spherical aberration, tilt or coma.

5. The wavefront-controlled continuous-range intraocular lens according to claim 1, characterized in that: The optical surface type expression of the aspheric surface is as follows: （5） Among them, Z(r) is the aspheric surface function, r is the radial coordinate, the distance from the center point of the lens on the optical axis, R is the curvature radius of the basic sphere, K is the quadratic surface coefficient, is the coefficient of the aspheric high-order term, i=1,2,…,n, n is a natural number not less than 1; when K=0, and the coefficient of the aspheric high-order term When both are 0, the surface is a sphere.

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