Intraocular lens with lens based on spatial filtering and preparation method of intraocular lens

Abstract

The invention provides a lens eye intraocular lens based on spatial filtering and a preparation method thereof.The lens eye intraocular lens comprises an optical body, and the optical body comprises an optical surface and an optical surface with a spatial filtering structure; the spatial filtering structure satisfies a filtering function capable of changing the spatial frequency spectrum of the imaging light beam to expand the focal depth. The imaging process generally refracted from geometrical optical light is used as the imaging process of wavefront transformation, and the optical surface with the spatial filtering structure is introduced into the intraocular lens with the lens to serve as a filter to change the filtering function of the filtering structure, so that the spatial frequency spectrum structure of an imaging light beam can be changed, and the purposes of expanding the focal depth and improving the imaging efficiency are achieved. Dynamic vision is enhanced, and the effects of correcting myopia and presbyopia are achieved; and a better visual effect is achieved. The tolerance to bad effects such as eccentric inclination and the like is high; the structure is simple and the stability is good.

Description

Technical Field

[0001] The present invention relates to the field of ophthalmic medical instruments and preparation technology, and in particular to a crystalline intraocular lens based on spatial filtering and a preparation method thereof. Background Art

[0002] There are many factors that cause refractive errors in the human eye. The most common ones are bad eye habits, long-term use of electronic devices, fewer outdoor activities and other factors. People use their eyes at close range for a long time, which causes abnormal growth of the eye axis, thus causing refractive errors. Changes in the size of the eye axis caused by the aging of natural glasses can also cause refractive errors. With the development of ophthalmic technology and the improvement of human demand for vision, many corrective methods have emerged in modern society to restore patients' vision, such as laser surgery, traditional frame glasses, contact lenses, and implanted lenses. Compared with corneal laser surgery, traditional frame glasses, contact lenses and other correction methods, implantable crystalline artificial lenses (ICL, Implantable Collamer Lens) have the advantages of not damaging the cornea, no need to remove or wear, and can be removed and replaced a second time, and are chosen by more and more young patients.

[0003] However, as the age of myopic people increases, the adjustment ability of ciliary muscles weakens, and the problem of presbyopia arises. There will be a large number of patients who suffer from both myopia and presbyopia. At present, there is no product that can correct myopia and presbyopia at the same time in the domestic market for correcting refractive errors; related products on the international market use a concentric ring free-form surface refraction design, which has a poor effect on correcting presbyopia, and has large imaging interference after correction, poor dynamic vision, and is difficult to meet the needs of patients for sports and driving. The Chinese invention patent with publication number CN115844587A discloses an extended depth of focus posterior chamber phakic intraocular lens and a preparation method thereof, which introduces a free-form surface through a geometric iteration method, applies the depth of focus extension technology to the phakic intraocular lens, and extends the depth of focus; in order to enrich the development and application of posterior chamber phakic intraocular lenses, overcome the shortcomings of the above-mentioned concentric ring free-form surface refraction design, and develop another posterior chamber phakic intraocular lens that can solve myopia and presbyopia at the same time, and improve the imaging quality of continuous vision. Summary of the invention

[0004] The purpose of the present invention is to solve the above-mentioned technical problems and to provide a phakic intraocular lens based on spatial filtering, which can simultaneously solve the problems of myopia and presbyopia and improve the imaging quality of continuous vision; another purpose of the present invention is to provide a method for preparing the phakic intraocular lens based on spatial filtering.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A phakic intraocular lens based on spatial filtering comprises an optical body, wherein the optical body comprises an optical surface and an optical surface having a spatial filtering structure, wherein the spatial filtering structure satisfies a filtering function capable of changing the spatial spectrum of an imaging light beam to extend the focal depth.

[0007] The present invention introduces an optical surface with a spatial filtering structure into a phakic intraocular lens as a filter. By changing the filtering function of the filtering structure, the spatial spectrum structure of the imaging light beam can be changed, thereby achieving the effect of extending the focal depth and correcting myopia and presbyopia at the same time.

[0008] Furthermore, the optical surface is a spherical surface or an aspherical surface, and an arbitrary spatial rectangular coordinate system is established with the vertex of the optical surface as the origin O and the optical axis as the Z axis. The abscissa axis X axis and the coordinate axis Y axis of the coordinate system are tangent to the optical surface, and the surface shape of the aspherical surface satisfies the aspherical surface equation (I) on the above YZ plane:

[0009]

[0010] Where Z(y) is the curve expression of the aspheric surface on the two-dimensional coordinate plane YZ, c is the reciprocal of the radius of curvature of the base spherical surface of the aspheric surface, y is the vertical distance from any point on the curve to the horizontal axis Z, A 2i is the aspheric high-order coefficient, m and n are both integers not less than 1 and n>m, K is the aspheric coefficient; when K and A 2i When it is 0, Z(y) is the equation of the sphere.

[0011] Furthermore, the filter function is on the XY plane, and the filter function H(x, y) satisfies formula (II):

[0012]

[0013] in, represents the light wave function of the incident plane light; represents the imaging light wave function;

[0014] The wave function of incident plane light is:

[0015]

[0016] in, is the modulus of the wave vector; A represents the amplitude, which is a constant and satisfies 0.5≤A≤3; is the initial phase of the incident plane light;

[0017] The imaging light wave function is formula (IV):

[0018]

[0019] Where f is the focal length of the imaging lens.

[0020] Furthermore, the filter function H(x, y) is a transfer function of a Butterworth, Chebyshev, elliptic or Bessel filter.

[0021] Furthermore, the phakic intraocular lens based on spatial filtering also includes a support haptic located on the periphery of the optical body, the support haptic includes a first support haptic and a second support haptic, and the optical body and the support haptic are integrally formed.

[0022] Further, the focal length f of the optical body is determined by the optical power of the optical body, and the optical power ranges from +3D to -21D.

[0023] Furthermore, the effective optical zone area of ​​the optical body ranges from 4.5 mm to 5.5 mm.

[0024] Furthermore, the extended focal depth of the optical body ranges from 1.0D to 2.5D.

[0025] Preferably, the optical body is made of hydrophilic polyacrylate.

[0026] Preferably, the optical body has a refractive index of 1.452 at 35°C.

[0027] Furthermore, the thickness of the first support haptic and the second support haptic is 0.08 mm to 0.15 mm.

[0028] The present invention also provides a method for preparing the above-mentioned phakic intraocular lens based on spatial filtering, comprising the following steps:

[0029] S1. Optical design: determine the focal length and effective optical area of ​​the optical subject; build a model in Zemax and optimize the basic sphere; obtain the required imaging wave function under the target extended focal depth based on the wave function of the incident light, the imaging wave function through the basic sphere and the target extended focal depth; obtain the filter function H(x, y) based on the relationship between the filter and imaging; calculate the spatial filter structure h of the filter based on the filter function H(x, y);

[0030] The filter function H(x, y) satisfies formula (II):

[0031] , in, represents the light wave function of the incident plane light; represents the imaging light wave function;

[0033] The wave function of incident plane light is:

[0034]

[0035] in, is the modulus of the wave vector; A represents the amplitude, which is a constant, usually 0.5≤A≤3; is the initial phase of the incident plane light;

[0036] The imaging light wave function is formula (IV):

[0037]

[0038] Where f is the focal length of the imaging lens;

[0039] S2. Turning and milling: According to the optical surface parameters of the optical design determined in step S1, write a lathe program for the hydrophilic material; use diamond single-point cutting technology to turn the optical body; write a milling machine program to mill the shape of the optical area and the loop foot;

[0040] S3. Perform low-temperature drum polishing on the intraocular lens to obtain a phakic intraocular lens based on spatial filtering.

[0041] The beneficial effects of the present invention are as follows:

[0042] (1) The present invention introduces an optical surface with a spatial filtering structure into a phakic intraocular lens as a filter. By changing the filtering function of the filtering structure, the spatial spectrum structure of the imaging light beam can be changed, thereby achieving the effect of extending the focal depth and correcting myopia and presbyopia at the same time.

[0043] (2) The present invention uses Abbe imaging theory to understand the imaging process usually obtained from the refraction of geometric optical light as an imaging process of wavefront transformation, and introduces a spatial filtering structure and adjusts its filtering function to achieve extended focal depth and enhanced dynamic vision, so that patients can correct presbyopia while correcting myopia, thus achieving better visual effects.

[0044] (3) The present phakic intraocular lens is different from the concentric refractive design on the market, which enhances the tolerance of the lens to adverse effects such as eccentric tilt. It has a simple structure and can be applied to complex ocular fluid environments. It has good stability and is not prone to induce complications. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a schematic diagram of the structure of the phakic intraocular lens based on spatial filtering of the present invention.

[0046] Figure 1 Labels: 1 is the optical body; 2 is the support haptic; 21 is the first support haptic; 22 is the second support haptic.

[0047] Figure 2This is the through-focus MTF curve of the phakic intraocular lens of comparative example 1.

[0048] Figure 3 This is the through-focus MTF curve of the phakic intraocular lens of Example 1.

[0049] Figure 4 This is a test chart of a phakic intraocular lens on a USAF1951 resolution plate based on spatial filtering in Example 1 of the present invention;

[0050] Figure 4 In the figure, a, b, c, d, e, f, g, and h respectively represent the imaging effects of resolution plates with an interval of 0.25D between -12D and -10.5D.

[0051] Figure 5 This is the through-focus MTF curve of the phakic intraocular lens of comparative example 2.

[0052] Figure 6 This is the through-focus MTF curve of the phakic intraocular lens of Example 2.

[0053] Figure 7 This is a test chart of a phakic intraocular lens based on spatial filtering on a USAF1951 resolution plate according to Example 2 of the present invention;

[0054] Figure 7 In the figure, a, b, c, d, e, and f respectively represent the imaging effects of resolution plates with an interval of 0.25D between -8D and -7D. DETAILED DESCRIPTION

[0055] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings 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 should fall within the scope of protection of the present invention.

[0056] Example 1

[0057] like Figure 1As shown, the present embodiment provides a phakic intraocular lens based on spatial filtering, comprising an optical body 1, wherein the optical body 1 comprises an optical surface and an optical surface having a spatial filtering structure, wherein the spatial filtering structure satisfies a filtering function that can change the spatial spectrum of an imaging light beam to extend the depth of focus. As an optional solution, the phakic intraocular lens based on spatial filtering further comprises a support haptic 2 located on the periphery of the optical body 1, wherein the support haptic 2 comprises a first support haptic 21 and a second support haptic 22, and the optical body 1 and the support haptic 2 are integrally formed. Preferably, the thickness of the first support haptic 21 and the second support haptic 22 can be any thickness between 0.08 mm and 0.15 mm, such as 0.08 mm, 0.15 mm, 0.1 mm, etc.

[0058] The optical surface is a spherical surface or an aspherical surface. With the vertex of the optical surface as the origin O and the optical axis as the Z axis, an arbitrary spatial rectangular coordinate system is established. The abscissa axis X and the coordinate axis Y of the coordinate system are tangent to the optical surface. The surface shape of the aspherical surface satisfies the aspherical surface equation (I) on the YZ plane:

[0059]

[0060] Where Z(y) is the curve expression of the aspheric surface on the two-dimensional coordinate plane YZ, c is the reciprocal of the radius of curvature of the base spherical surface of the aspheric surface, y is the vertical distance from any point on the curve to the horizontal axis Z, A 2i is the aspheric high-order coefficient, m and n are both integers not less than 1 and n>m, K is the aspheric coefficient; when K and A 2i When it is 0, Z(y) is the equation of the sphere.

[0061] The spatial filtering structure satisfies the filter function H(x, y) that can change the spatial spectrum of the imaging light beam to extend the focal depth and satisfies formula (II):

[0062]

[0063] in, represents the light wave function of the incident plane light; represents the imaging light wave function;

[0064] The wave function of incident plane light is:

[0065]

[0066] in, is the modulus of the wave vector; A represents the amplitude, which is a constant and satisfies 0.5≤A≤3; is the initial phase of the incident plane light;

[0067] The imaging light wave function is formula (IV):

[0068]

[0069] Where f is the focal length of the imaging lens.

[0070] As an optional solution, the filter function H(x, y) is a transmission function of a Butterworth, Chebyshev, elliptic or Bessel filter, or a custom filter function. After the incident light wave passes through the filter, the imaging effect is finally changed on the image plane to achieve the effect of extended depth of focus.

[0071] As an optional solution, the focal length f of the optical body 1 is determined by the optical power of the optical body 1, and the optical power ranges from +3D to -21D. The effective optical zone area of ​​the optical body 1 can range from 4.5mm to 5.5mm, and the extended focal depth of the optical body 1 ranges from 1.0D to 2.5D.

[0072] As an optional solution, the optical body 1 is made of hydrophilic polyacrylate; the refractive index of the optical body 1 at 35° C. is 1.452. Of course, those skilled in the art can also modify the material and refractive index according to actual needs.

[0073] The present invention also provides a method for preparing the above-mentioned phakic intraocular lens based on spatial filtering, comprising the following steps:

[0074] S1. Optical design: determine the focal length and effective optical area of ​​the optical body 1; build a model in Zemax and optimize the basic sphere; obtain the required imaging wave function under the target extended focal depth according to the wave function of the incident light, the imaging wave function through the basic sphere and the target extended focal depth; obtain the filter function H(x, y) according to the relationship between the filter and the imaging; calculate the spatial filter structure h of the filter according to the filter function H(x, y);

[0075] The filter function H(x, y) satisfies formula (II):

[0076]

[0077] ,in, represents the light wave function of the incident plane light; represents the imaging light wave function;

[0078] The wave function of incident plane light is:

[0079]

[0080] in, is the modulus of the wave vector; A represents the amplitude, which is a constant, usually 0.5≤A≤3; is the initial phase of the incident plane light;

[0081] The imaging light wave function is formula (IV):

[0082]

[0083] Where f is the focal length of the imaging lens;

[0084] S2. Turning and milling: According to the optical surface parameters of the optical design determined in step S1, write a lathe program for the hydrophilic material; use diamond single-point cutting technology to turn the optical body 1; write a milling machine program to mill the shape of the optical area and the loop foot;

[0085] S3. Perform low-temperature drum polishing on the intraocular lens to obtain a phakic intraocular lens based on spatial filtering.

[0086] Specifically, Figure 1 As shown, a phakic intraocular lens (ICL) based on spatial filtering includes an optical body 1, a first support haptic 21 and a second support haptic 22, wherein the optical body 1 has an optical surface with a spatial filtering structure, and the spatial filtering structure satisfies a filtering function that can change the spatial spectrum of an imaging light beam to extend the depth of focus.

[0087] The optical body 1, the first support haptic 21 and the second support haptic 22 are an integrated structure, made of the same material and integrally formed; the optical body 1 is made of hydrophilic polyacrylate with a refractive index of 1.443 at 35°C.

[0088] The method for preparing the phakic intraocular lens based on spatial filtering is as follows:

[0089] S1. Optical design: Determine the focal power of the optical body 1 to be -12D and the effective optical area to be 5.5mm, with a target extended focal depth of 1.5D; model the model in Zemax and optimize the curvature of the base sphere r = 9.26mm and the aspheric coefficient K = -0.

[0090] 226, is a concave surface, and the other surface is a plane; the incident light is a plane light with an initial phase of 0 and an amplitude of A=1, and its light wave function is formula (V):

[0091]

[0092] After passing through the basic lens, the imaging light wave function of f=-0.0833 is formula (VI):

[0093]

[0094] According to the target extended focal depth range of 1.5D, the required imaging light wave function can be obtained as formula (VII):

[0095]

[0096] Where b=44mm, which is the period; A1 is the amplitude. The amplitude is not modulated here, so A1=1.

[0097] Since the relationship between the filter and imaging is as follows:

[0098]

[0099] We can get formula (VIII):

[0100]

[0101] The spatial filter structure h of the filter is calculated according to the filter function H(x, y) and superimposed on the base surface.

[0102] S2. Turning and milling: Write a lathe program for hydrophilic materials according to the optical surface parameters of the optical design; use diamond single-point cutting technology to turn the optical body 1; write a milling machine program to mill the shape of the optical area and the loop.

[0103] S3. Polishing: Use low-temperature drum polishing method to obtain an intraocular lens with a qualified optical surface.

[0104] Example 2

[0105] like Figure 1 As shown, a phakic intraocular lens (ICL) based on spatial filtering includes an optical body 1, a first support haptic 21 and a second support haptic 22, wherein the optical body 1 has an optical surface with a spatial filtering structure, and the spatial filtering structure satisfies a filtering function that can change the spatial spectrum of an imaging light beam to extend the depth of focus.

[0106] The optical body 1, the first support haptic 21 and the second support haptic 22 are an integrated structure, made of the same material and integrally formed; the optical body 1 is made of hydrophilic polyacrylate with a refractive index of 1.443 at 35°C.

[0107] The method for preparing the phakic intraocular lens based on spatial filtering is as follows:

[0108] S1. Optical design: The focal power of the crystal is determined to be -8D, the optical zone area is 5mm, and the extended focal depth is 1D. Based on the proposed focal power of the crystal and the optical zone area, the model is built in Zemax to optimize the curvature of the basic sphere r = 14.21mm, the non-curved surface coefficient K = -1.315, one surface is concave, and the other surface is flat. The incident light has an initial phase of The wave function of plane light with amplitude A = 0.8 is as follows:

[0109]

[0110] After passing through the basic lens, the imaging light wave function of f=-0.125 is formula (VI):

[0111]

[0112] According to the extended focal depth range of 1D, the required imaging light wave function can be obtained as formula (VII):

[0113]

[0114] Wherein b=50 mm is the period; the extended focal depth is enhanced, and the modulation amplitude A1=1.2.

[0115] Since the relationship between the filter and imaging satisfies formula (II):

[0116]

[0117] We can get formula (VIII):

[0118]

[0119] The spatial filter structure h of the filter is calculated according to the filter function H(x, y) and superimposed on the base surface.

[0120] S2. Turning and milling: Write a lathe program for hydrophilic materials according to the optical surface parameters of the optical design; use diamond single-point cutting technology to turn the optical body 1; write a milling machine program to mill the shape of the optical area and the loop.

[0121] S3. Polishing: Use low-temperature drum polishing method to obtain an intraocular lens with a qualified optical surface.

[0122] Comparative Example 1-2

[0123] A monofocal ICL with the same material and optical area as those in Example 1 and the same optical power of -12D is manufactured as Comparative Example 1.

[0124] A monofocal ICL with the same material and optical area as in Example 1 and the same focal power of -8D as in Example 2 is manufactured as Comparative Example 2.

[0125] Test Example 1

[0126] (1) Example 1 and Comparative Example 1 were introduced into the eye model required by ISO11979-2 and equipped with a 20D compensation lens, and the defocus MTF curves of the two were tested at 50 line pairs. The results of Comparative Example 1 are as follows: Figure 2 As shown, the results of Example 1 are as follows Figure 3 As shown, it can be seen that compared with comparative example 1, the focal depth range of embodiment 1 is larger, and the tested extended focal depth is greater than 1.5D.

[0127] The ICL in Example 1 was introduced into the eye model required by ISO11979-2 and equipped with a 20D compensation lens. The USAF1951 resolution plate test chart was used to simulate imaging once at intervals of 0.25D. Figure 4 As shown in Figure 2, it can be seen that the ICL has a continuous focal depth range from -12D to -10.5D.

[0128] (2) Example 2 and Comparative Example 2 were introduced into the eye model required by ISO11979-2 and equipped with a 20D compensation lens, and the defocus MTF curves of the two were tested at 50 line pairs. The results of Comparative Example 2 are as follows: Figure 5 As shown, the results of Example 1 are as follows Figure 6 As shown, it can be seen that compared with Comparative Example 2, the focal depth range of Example 2 is larger, and the tested extended focal depth is greater than 1D.

[0129] The ICL in Example 2 was introduced into the eye model required by ISO11979-2 and equipped with a 20D compensation lens. The USAF1951 resolution plate test chart was used to simulate imaging once at intervals of 0.25D. Figure 7 As shown in Figure 2, it can be seen that the ICL has a continuous focal depth range from -8D to -7D.

[0130] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the solution. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents based on the understanding of the present solution without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A phakic intraocular lens based on spatial filtering, characterized in that: The optical body (1) comprises an optical surface and an optical surface with a spatial filtering structure, wherein the spatial filtering structure satisfies a filtering function capable of changing the spatial spectrum of an imaging light beam to extend the focal depth.

2. The phakic intraocular lens based on spatial filtering according to claim 1, characterized in that: The optical surface is a spherical surface or an aspherical surface. With the vertex of the optical surface as the origin O and the optical axis as the Z axis, an arbitrary spatial rectangular coordinate system is established. The abscissa axis X and the coordinate axis Y of the coordinate system are tangent to the optical surface. The surface shape of the aspherical surface satisfies the aspherical surface equation (I) on the YZ plane: Wherein Z(y) is the curve expression of the aspheric surface on the two-dimensional coordinate plane YZ, c is the reciprocal of the radius of curvature of the base spherical surface of the aspheric surface, y is the vertical distance from any point on the curve to the horizontal axis Z, A2i is the high-order coefficient of the aspheric surface, m and n are both integers not less than 1 and n>m, and K is the aspheric coefficient; when K and A2i are 0, Z(y) is the spherical equation.

3. The phakic intraocular lens based on spatial filtering according to claim 1, characterized in that: The filter function H(x, y) satisfies formula (II): in, represents the light wave function of the incident plane light; represents the imaging light wave function; The wave function of incident plane light is: in, is the modulus of the wave vector; A represents the amplitude, which is a constant and satisfies 0.5≤A≤3; is the initial phase of the incident plane light; The imaging light wave function is formula (IV): Where f is the focal length of the imaging lens.

4. The phakic intraocular lens based on spatial filtering according to claim 1, characterized in that: The filter function H(x, y) is a transfer function of a Butterworth, Chebyshev, elliptic or Bessel filter.

5. The phakic intraocular lens based on spatial filtering according to claim 1, characterized in that: It also includes a support haptic (2) located on the peripheral side of the optical body (1), the support haptic (2) including a first support haptic (21) and a second support haptic (22), and the optical body (1) and the support haptic (2) are integrally formed.

6. The phakic intraocular lens based on spatial filtering according to claim 1, characterized in that: The focal length f of the optical body (1) is determined by the optical power of the optical body (1), and the optical power ranges from +3D to -21D.

7. The phakic intraocular lens based on spatial filtering according to claim 1, characterized in that: The effective optical zone area of ​​the optical body (1) ranges from 4.5 mm to 5.5 mm.

8. The phakic intraocular lens based on spatial filtering according to claim 1, characterized in that: The extended focal depth of the optical body (1) ranges from 1.0D to 2.5D.

9. The phakic intraocular lens based on spatial filtering according to claim 1, characterized in that: The thickness of the first support haptic (21) and the second support haptic (22) is 0.08 mm to 0.15 mm.

10. The method for preparing a phakic intraocular lens based on spatial filtering according to any one of claims 1 to 9, comprising the following steps: S1. Optical design: determine the focal length and effective optical area of ​​the optical body (1); build a model in Zemax and optimize the basic sphere; obtain the required imaging wave function under the target extended focal depth based on the wave function of the incident light, the imaging wave function of the incident light through the basic sphere and the target extended focal depth; obtain the filter function H(x, y) based on the relationship between the filter and the imaging; calculate the spatial filter structure h of the filter based on the filter function H(x, y); The filter function H(x, y) satisfies formula (II): ， in, represents the light wave function of the incident plane light; represents the imaging light wave function; The wave function of incident plane light is: in, is the modulus of the wave vector; A represents the amplitude, which is a constant, usually 0.5≤A≤3; is the initial phase of the incident plane light; The imaging light wave function is formula (IV): Where f is the focal length of the imaging lens; S2. Turning and milling: According to the optical surface parameters of the optical design determined in step S1, write a lathe program for the hydrophilic material; use diamond single-point cutting technology to turn the optical body (1); write a milling machine program to mill the shape of the optical area and the loop foot; S3. Perform low-temperature drum polishing on the intraocular lens to obtain a phakic intraocular lens based on spatial filtering.

Images