Vision correction lens and method for preparation of the same

Abstract

The present invention discloses a method for making an aspheric vision correction lens with controlled peripheral defocus. The present invention also discloses a vision correction lens worn outside the eye, an orthokeratology lens and an intraocular lens made according to the method. The present invention further discloses a diagnosis and treatment method that utilizes myopic peripheral defocus to control and retard myopia growth.

Claims

1. A vision correction lens, the vision correction lens having an optical zone which comprises an aspheric surface, a surface shape of the aspheric surface is configured such that upon the vision correction lens interacting with a human eye, the distribution of the refractive power of the entire eye towards the retina is greater in the peripheral region of the retina than in the central region of the retina, and falls in front of the retina, to form myopic defocus, characterized in that the vision correction lens being an orthokeratology lens, wherein the optical zone is a base curve zone of the orthokeratology lens, wherein the base curve zone is configured to be in contact with a central region of a cornea of the human eye, the shape of the aspheric surface of the base curve zone of the orthokeratology lens is defined by a scale factor η of equivalent radii of curvature; the scale factor η of the equivalent radii of curvature of the aspheric surface is less than 1; scale factor η is a ratio of equivalent radii of curvature of the orthokeratology lens at a first diameter and a second diameter d.sub.n, wherein the first diameter is greater than the second diameter, $η = \frac{r_{m}}{r_{n}}$ the equivalent radius of curvature of the base curve zone of the orthokeratology lens is calculated in the following way: $r_{m} = \frac{{(\frac{d_{m}}{2})}^{2} + h_{m}^{2}}{2 h_{m}} = \frac{{(d_{m})}^{2} + 4 h_{m}^{2}}{8 h_{m}},$ wherein d.sub.m is the measured aperture at the first diameter; M.sub.m is the point at the aperture d.sub.m; h.sub.m the sagittal height of point M.sub.m, i.e., the difference in height between point M.sub.m and the vertex of the aspheric surface; and r.sub.m is the equivalent radius of curvature at point M.sub.m, $r_{n} = \frac{{(\frac{d_{n}}{2})}^{2} + h_{n}^{2}}{2 h_{n}} = \frac{{(d_{n})}^{2} + 4 h_{n}^{2}}{8 h_{n}},$ wherein d.sub.n is the measured aperture at the second diameter: M.sub.n is the point at the aperture d.sub.n; h.sub.n is the sagittal height of point M.sub.n i.e., the difference in height between point M.sub.n and the vertex of the aspheric surface; and r.sub.n is the equivalent radius of curvature at point M.sub.n.

2. The vision correction lens according to claim 1, characterized in that the scale factor 1153 of the equivalent radii of curvature of the aspheric surface of the base curve zone of the lens at a 5 mm aperture and a 3 mm aperture is greater than or equal to 0.67 and less than or equal to 0.998.

3. The vision correction lens according to claim 1, characterized in that the scale factor η.sub.53 of the equivalent radii of curvature of the aspheric surface of the base curve zone of the lens at a 5 mm aperture and a 3 mm aperture is greater than or equal to 0.67 and less than 1.

4. The vision correction lens according to claim 1, characterized in that the scale factor η.sub.53 of the equivalent radii of curvature of the aspheric surface of the base curve zone of the lens at a 5 mm aperture and a 3 nm aperture is greater than or equal to 0.67 and less than 0.991.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic diagram of the retina, myopic defocus and hyperopic defocus;

(2) FIG. 2 is a schematic diagram of a curve of distribution of diopter of myopic peripheral defocus of the present invention;

(3) FIG. 3 is a schematic diagram of an expression of the curve of an aspheric surface of the present invention;

(4) FIG. 4 is a schematic diagram of the parameters to which the scale factor η of the present invention is related;

(5) FIG. 5 is a schematic diagram of the structure of Example 1 of the present invention;

(6) FIG. 6 is a schematic diagram of the structure of Example 2 of the present invention;

(7) FIG. 7 is a radial schematic diagram of the lens of the present invention;

(8) FIG. 8 is a flow diagram of an vision correction lens diagnosis and treatment method of the present invention;

(9) FIG. 9 is a schematic diagram of the retina and refractive power distribution of the present invention;

(10) FIG. 10 is a flow diagram of Example 3 of the present invention;

(11) FIG. 11 is a flow diagram of Example 4 of the present invention;

(12) FIG. 12 is a schematic diagram of a longitudinal central section of an existing orthokeratology lens having an inner surface designed as four curve zones;

(13) FIG. 13 is a schematic diagram of the refractive power distribution of an existing spherical cornea having a refractive power of 42.25D and an aspheric cornea having an aspheric coefficient Q value of −0.25 and a refractive power of 42.25D at different apertures;

(14) FIG. 14 is a schematic diagram of the structure of an orthokeratology lens of the present invention;

(15) FIG. 15 is a schematic diagram of the structure of an intraocular lens of the present invention;

(16) FIG. 16 is a side view of FIG. 15.

(17) FIG. 17 is a schematic diagram of the structure of another intraocular lens of the present invention;

(18) FIG. 18 is a side view of FIG. 17.

(19) FIG. 19 is a schematic diagram of the refractive power distribution of the present invention and the refractive power distribution of the prior art; and

(20) FIG. 20 is a schematic diagram of surface shapes of an aspheric surface of the present invention and an aspheric surface of the prior art.

DETAILED DESCRIPTION OF EMBODIMENTS

(21) For easy understanding of the technical means, creative features, objects and effects of the present invention, the present invention will be further described below with reference to the specific drawings.

Definitions of the Terms

(22) The term “myopic peripheral defocus” as used in the present application means that the peripheral region has a refractive power greater than that of the central region. When the central image points fall on the retina, the peripheral image points fall in front of the retina, it is defined that the amount of peripheral defocus ΔD is greater than 0.

(23) The term “hyperopic peripheral defocus” as used in the present application means that the peripheral region has a refractive power less than that of the central region. When the central image points fall on the retina, the peripheral image points fall behind of the retina, it is defined that the amount of defocus ΔD is less than 0.

(24) The term “refractive power”, as used in this application, is a measurement of the degree to which a lens refracts light. “Diopter” is a measurement of the magnitude of the refractive power. There are positive and negative diopters. The signs are also taken into account when comparing the diopters. For example, where D1=10.0D and D2=15.0D, D1<D2; where D3=−10.0D and D4=−15.0D, D3>D4.

(25) The term “optical zone” as used in the present application refers to the main functional portion in the central region of the lens that has optical properties and can thus achieve adjustment of the diopter of the lens.

(26) The term “haptic” or “support haptic” as used in the present application refers to the portion that is connected with the optical portion of the lens and functions to support the optical portion and position the lens in the human eye.

(27) The term “radial” as used in the present application refers to the direction of a straight line from the lens center along the radius or diameter.

(28) The term “aperture” as used in the present application refers to the radial diameter of the lens surface.

(29) Terms indicating positional relationship in the present application, such as “anterior” and “posterior” are used based on the distance to the surface of the cornea of the eye. For example, for a lens of the present application, the “posterior surface of the optical portion” is an optical surface that is closer to the cornea of the eye than the “anterior surface of the optical portion”.

(30) The term “base spherical surface” as used in the present application refers to an ideal spherical surface having the same designed value of radius of curvature corresponding to the various shapes taken by the anterior and posterior surfaces of the optical portion of the lens. In the present application, in order to make the terms consistent, the ideal spherical surfaces are collectively referred to as “base spherical surface”.

(31) The terms “steep” and “flat” as used in the present application are descriptions of the greatness of the equivalent radius of curvature of the lens. For example, in the present application, “steeper than the spherical surface” means that the absolute value of the equivalent radius of curvature of the lens is smaller than the absolute value of the radius of curvature of the base spherical surface; and “flatter than the spherical surface” means that the absolute value of the equivalent radius of curvature of the lens is greater than the absolute value of the radius of curvature of the base spherical surface.

(32) The term “convex surface” as used in the present application refers to a surface which is always below the tangent plane made through any point on the surface; “concave surface” refers to a surface which is always above the tangent plane made through any point on the surface.

(33) Similar to shown in FIG. 6, a vision correction glasses worn outside the eye according to one aspect of the present invention comprise a lens. At least one of the convex surface 101 or the concave surface 102 of the optical zone 100 of the lens is aspheric. When the convex surface 101 of the optical zone 100 of the lens is aspheric, the equivalent radius of curvature of the periphery of the optical zone 100 of the lens is smaller than the radius of curvature of the center of the optical zone 100 of the lens; and when the concave surface 102 of the optical zone 100 of the lens is aspheric, the equivalent radius of curvature of the periphery of the optical zone 100 of the lens is greater than the radius of curvature of the center of the optical zone 100 of the lens.

(34) As shown in FIG. 2, the refractive power of the lens in the air is less than or equal to 0D. The refractive power of the lens increases radially as the aperture increases, and the absolute value of the refractive power of the lens decreases as the aperture increases.

(35) FIG. 7 is a radial schematic diagram of a lens of the present invention, wherein A is a front view of the lens of the present invention, and B shows the radial direction of the lens of the present invention.

(36) The difference between the refractive power of the lens at the 5 mm aperture and the refractive power of the lens at the 3 mm aperture Δ D.sub.53 is greater than or equal to 0.005D, preferably greater than or equal to 0.005D and less than or equal to 8.849D.

(37) As shown in FIG. 3, the expression of the aspheric surface of the optical zone 100 of the lens is:

(38) $Z (y) = \frac{{cy}^{2}}{1 + \sqrt{1 - (1 + Q) c^{2} y^{2}}} + {.Math.}_{i = 2}^{5} A_{2 i} • y^{2 i}$

(39) wherein c is the reciprocal of the radius of curvature of the base spherical surface of the optical portion, y is the vertical distance from any point on the curve to the abscissa axis (Z), Q is aspheric coefficient, A.sub.2i is aspheric high-order term coefficient, and the aspheric surface is obtained from the aspheric surface curve through rotationally symmetric variation about the abscissa axis (Z).

(40) As shown in FIG. 4, the shape of the aspheric surface of the optical zone 100 of the lens is defined by the scale factor η of equivalent radii of curvature, and η is a ratio of r at different apertures d.sub.m and d.sub.n, wherein m>n,

(41) $η_{mn} = \frac{r_{m}}{r_{n}}$

(42) When the concave surface 102 of the optical zone 100 of the lens is an aspheric surface, the scale factor η of the equivalent radii of curvature of the aspheric surface is greater than 1. When the convex surface 101 of the optical zone 100 of the lens is an aspheric surface, the scale factor η of the equivalent radii of curvature of the aspheric surface is less than 1.

(43) The equivalent radius of curvature of the optical zone 100 of the lens is calculated in the following way:

(44) $r_{m} = \frac{{(\frac{d_{m}}{2})}^{2} + h_{m}^{2}}{2 h_{m}} = \frac{{(d_{m})}^{2} + 4 h_{m}^{2}}{8 h_{m}},$
wherein d.sub.m is the measured aperture, M is the point at the aperture d.sub.m, h.sub.m is the sagittal height of point M, i.e., the difference in height between point M and the vertex of the aspheric surface, and r.sub.m is the equivalent radius of curvature at point M.

(45) When the concave surface 102 of the optical zone 100 of the lens is an aspheric surface, the scale factor η.sub.53 of the equivalent radii of curvature of the aspheric surface at the 5 mm aperture and the 3 mm aperture is preferably greater than or equal to 1.002 and less than or equal to 1.086.

(46) When the convex surface 101 of the optical zone 100 of the lens is an aspheric surface, the scale factor η.sub.53 of the equivalent radii of curvature of the aspheric surface at the 5 mm aperture and the 3 mm aperture is preferably greater than or equal to 0.682 and less than or equal to 0.986.

Example 1

(47) As shown in FIG. 5, in this example, the vision correction lens is a cornea contact lens. The shape of the concave surface 102′ (the surface in direct contact with the cornea) of the optical zone 100′ of the lens is consistent with the shape the surface of the cornea, namely a spherical surface or aspheric surface consistent with the form of the cornea. The convex surface 101′ of the optical zone 100′ of the lens has an aspheric structure of the present invention. The aspheric structure of the present invention is as described above.

(48) In this example, the scale factor η.sub.53 of the equivalent radii of curvature of the aspheric surface at the 5 mm aperture and the 3 mm aperture is preferably greater than or equal to 0.682 and less than or equal to 0.986, and the difference in the refractive power ΔD.sub.53 is greater than or equal to 0.130D and less than or equal to 4.779D.

(49) For specific examples, see Table 1, wherein Rp and Qp are the radius of curvature and aspheric coefficient of the convex surface (the surface in direct contact with the cornea) of the contact lens; Ra, Qa, A4, A6 and A8 are the radius of curvature, aspheric coefficient and higher-order aspheric coefficients of the anterior surface of the contact lens, respectively; ΔD.sub.53 is the difference between the refractive power of the lens at the 5 mm aperture and the refractive power of the lens at the 3 mm aperture; and η.sub.53 is a scale factor of the equivalent radii of curvature of the aspheric surface of the lens at the 5 mm aperture and the 3 mm aperture.

(50) TABLE-US-00001 TABLE 1 Examples of Cornea Contact Lenses Refractive index Diopter/D Rp/mm Qp Ra/mm Qa A4 A6 A8 ΔD.sub.53 η.sub.53 1.415 −20 10.00 −0.25 19.581 2.412 5.402E−05 −3.762E−08 −1.091E−09 0.130 0.986 1.400 −30 11.166 0 76.890 291.247 2.553E−04 1.612E−06 −1.875E−07 1.690 0.835 1.400 −30 11.166 0 93.392 772.250 7.205E−04 4.236E−06 −1.721E−06 4.723 0.682 1.500 −30 10 0 27.443 31.184 5.526E−04 −5.714E−06 −2.844E−07 4.757 0.875 1.400 −30 10 0 48.019 185.239 6.685E−04 1.051E−06 −1.972E−06 4.734 0.779 1.400 −30 10 0 43.144 86.798 2.367E−04 8.245E−07 −2.729E−07 1.715 0.887 1.400 −10 10 0 13.539 1.401 9.163E−05 6.267E−07 −8.348E−11 0.714 0.982 1.400 −30 10 0 42.604 67.215 1.931E−04 2.685E−07 −9.757E−08 1.188 0.907 1.400 −10 10 0 13.512 1.277 6.053E−05 3.763E−07 3.089E−09 0.452 0.986 1.400 −30 10 0 41.966 52.149 1.393E−04 −1.554E−07 −4.106E−08 0.618 0.929 1.432 −15 5 0 6.194 0.199 3.103E−04 3.952E−06 3.853E−07 0.269 0.980 1.432 −15 7.8 0 10.859 0.664 1.035E−04 5.140E−07 1.131E−08 0.191 0.986 1.432 −30 5 0 7.970 1.175 4.929E−04 4.910E−06 1.295E−07 0.868 0.952 1.432 −30 7.8 0 17.585 2.136 2.707E−04 1.162E−06 1.410E−08 0.570 0.957 1.432 −30 10 0 33.922 25.348 1.168E−04 −4.114E−09 −2.754E−08 0.476 0.949 1.432 −15 5 0 6.192 0.230 3.032E−04 3.710E−06 3.520E−07 0.352 0.966 1.432 −15 10 0 15.536 1.451 6.693E−05 2.190E−07 5.918E−09 0.253 0.976 1.432 −30 5 0 7.982 1.132 5.279E−04 4.478E−06 2.113E−07 1.005 0.920 1.432 −30 10 0 34.020 28.649 1.254E−04 −1.425E−07 −2.733E−08 0.623 0.909 1.432 −30 5 0 8.006 1.496 5.064E−04 3.737E−06 −9.895E−08 1.539 0.947 1.432 −30 10 0 34.391 35.500 1.763E−04 2.033E−07 −5.459E−08 1.190 0.927 1.432 −30 5 0 8.026 1.498 5.799E−04 3.795E−06 −1.053E−07 2.032 0.944 1.432 −30 10 0 34.753 42.723 2.232E−04 9.326E−07 −1.499E−07 1.723 0.911 1.432 −30 5 0 8.047 1.581 6.355E−04 2.547E−06 −1.434E−07 2.490 0.941 1.432 −30 10 0 30.107 46.095 2.828E−04 1.180E−06 −1.965E−07 2.209 0.890 1.432 −30 5 0 8.075 1.922 6.570E−04 2.717E−08 −4.791E−07 3.128 0.936 1.432 −30 10 0 35.665 69.042 3.237E−04 −4.695E−07 −5.382E−07 2.879 0.877 1.432 −30 10 0 37.482 118.917 5.157E−04 1.713E−06 −2.677E−06 4.779 0.823 1.432 −30 5 −0.25 7.985 0.952 3.945E−04 4.615E−07 −7.752E−08 1.502 0.963 1.432 −30 10 −0.25 34.219 32.089 1.536E−04 1.739E−07 −3.938E−08 0.582 0.935 1.432 −30 5 −0.25 8.017 1.008 4.586E−04 −8.108E−08 −9.179E−08 2.001 0.960 1.432 −30 10 −0.25 34.763 40.819 2.014E−04 1.339E−07 −9.593E−08 1.470 0.918 1.432 −30 5 −0.5 8.016 0.718 2.862E−04 −2.794E−06 −1.090E−07 1.981 0.974 1.432 −30 10 −0.5 34.765 37.245 1.816E−04 1.326E−07 −6.647E−08 1.712 0.925 1.432 −30 10 −1 34.770 31.281 1.385E−04 2.832E−07 −2.820E−08 1.707 0.939 1.710 −30 10 0 18.205 9.161 3.391E−04 −4.381E−06 −1.337E−07 4.739 0.934

Example 2

(51) In this example, the vision correction lens is frame glasses. At least one of the convex surface 101 or the concave surface 102 of the optical zone 100 of the lens has the aspheric surface structure of the present invention as described above.

(52) The convex surface 101 of the optical zone 100 of the lens has the aspheric surface structure of the present invention. The structure is similar to that in Example 1. The equivalent radius of curvature in the periphery is to smaller than in the center, and the surface in the periphery is steeper than a spherical surface such that the surface changes uniformly in the direction of the aperture according to the set refractive power distribution.

(53) As shown in FIG. 6, when the aspheric surface structure of the present invention is on the concave surface 102 of the optical zone 100 of the lens, since the surface on which the aspheric surface is located provides the lens with a negative refractive power, the absolute value of the refractive power provided by the lens at a larger aperture should be smaller than that at a smaller aperture in order for the lens to have a refractive power distribution the same as that of the present invention. In order to achieve the same refractive power control, the surface in the periphery should obviously be flatter than the spherical surface.

(54) In this example, the scale factor η.sub.53 of the equivalent radii of curvature of the aspheric surface at the 5 mm aperture and the 3 mm aperture is preferably greater than or equal to 1.002 and less than or equal to 1.086, and the difference in the refractive power ΔD.sub.53 is greater than or equal to 0.005D and less than or equal to 8.849D.

(55) For specific examples, see Table 2, wherein Rp and Qp are the radius of curvature and aspheric coefficient of the convex surface (the surface in direct contact with the cornea) of the contact lens; Ra, Qa, A4, A6 and A8 are the radius of curvature, aspheric coefficient and higher-order aspheric coefficients of the convex surface of the contact lens, respectively; ΔD.sub.53 is the difference between the refractive power of the lens at the 5 mm aperture and the refractive power of the lens at the 3 mm aperture; and η.sub.53 is a scale factor of the equivalent radii of curvature of the aspheric surface of the lens at the 5 mm aperture and the 3 mm aperture.

(56) TABLE-US-00002 TABLE 2 Examples of Frame Glasses Refractive index Ra Rp Qp A4 A6 A8 ΔD.sub.53 η.sub.53 1.43 10.428 6.869 −0.727 −3.81E−04 −1.33E−06 2.85E−08 3.047 1.036 1.43 10.428 6.869 −1.000 0 0 0 1.040 1.021 1.43 10.428 6.869 −2.000 0 0 0 3.429 1.040 1.43 10.428 6.869 −5.000 0 0 0 7.939 1.086 1.50 9.773 7.000 −5.000 0 0 0 8.662 1.083 1.70 8.807 7.000 −5.000 0 0 0 8.849 1.083 1.43 8.368 5.502 0.215 −7.247E−04 −1.067E−05 −1.003E−06 0.392 1.024 1.55 7.724 5.954 −0.157 −2.029E−04 −2.378E−06 −9.978E−08 0.227 1.014 1.71 7.275 5.964 −0.123 −1.562E−04 −1.820E−06 −9.407E−08 0.225 1.011 1.71 6.203 5.996 −0.019 −2.161E−05 −1.861E−07 −2.286E−08 0.005 1.002

(57) Of course, for the frame glasses, both the convex surface and the concave surface of the lens may be of the aspheric surface structure of the present invention, besides that only one of them has the aspheric surface structure of the present invention. It is unnecessary to repeat the details here.

(58) On the basis of the present invention's concept of controlling myopic growth by myopic peripheral defocus and aspheric surface design of the lens, those skilled in the art may also conceive making, through contrary modified control of the lens, the absolute value of the refractive power of the lens at a larger aperture greater than that at a smaller aperture, to achieve hyperopic peripheral defocus of the human eye to thereby treat hyperopia by actively facilitating increase of the axial length of the human eye.

(59) As shown in FIG. 8, a method for preparing an aspheric vision correction lens with controllable peripheral defocus according to one aspect of the present invention comprises the steps of:

(60) (1) calculating and determining the conditions required for the formation of myopic defocus of a human eye by examining the shape of the retina of the human eye, the amount of peripheral defocus of the naked human eye or the amount of peripheral defocus of the human eye with a lens;

(61) (2) formulating a plan of distribution of the refractive power of the vision correction lens varying with the aperture, according to the conditions obtained for myopic defocus; and

(62) (3) manufacturing a vision correction lens according to the obtained plan of distribution of the refractive power of the vision correction lens such that after the refractive power of the vision correction lens is added to the human eye, the distribution of the refractive power of the entire eye on the retina is greater in the peripheral region of the retina than in the central region, and falls in front of the retina, to form myopic defocus.

(63) As shown in FIG. 9, B is the retina, and C is the curve of distribution of the refractive power of the entire eye on the retina. The shape of the retina, the amount of peripheral defocus of the naked human eye and the amount of peripheral defocus of the human eye with a lens may be measured by an ophthalmic test apparatus.

(64) The shape of the retina of the human eye is measured by an ophthalmic test apparatus (such as an Optical Coherence Tomograph OCT). The ophthalmic test apparatus regards the retina as a spherical surface, and measures the shape of the retina by its radius of curvature.

(65) The shape of the retina of the human eye is measured by an ophthalmic test apparatus. The ophthalmic test apparatus regards the retina as an aspheric surface, and measures the shape of the retina by the equivalent radius of curvature of the aspheric surface. The equivalent radius of curvature of the aspheric surface is calculated in the following way

(66) $r_{m} = \frac{{(\frac{d_{m}}{2})}^{2} + h_{m}^{2}}{2 h_{m}} = \frac{{(d_{m})}^{2} + 4 h_{m}^{2}}{8 h_{m}},$
wherein d.sub.m is the measured aperture; M is the point at the aperture d.sub.m; h.sub.m is the sagittal height of point M, i.e., the difference in height between point M and the vertex of the aspheric surface; and r.sub.m is the equivalent radius of curvature at point M.

(67) The distribution of the refractive power of the entire eye formed by the vision correction lens and the human eye meets:

(68) $\frac{1}{D_{r}} = \frac{1}{D_{0}} - r + \sqrt{R^{2} - r^{2}}$

(69) The distribution of the refractive power of the entire eye formed by the vision correction lens and the human eye causes myopic defocus with respect to the shape of the retina, and meets:

(70) $.Math. \frac{1}{D_{t}^{'}} .Math. < .Math. \frac{1}{D_{r}} .Math. = .Math. \frac{1}{D_{0}} - r + \sqrt{R^{2} - r^{2}} .Math.$
wherein D.sub.r is the refractive power of the entire eye at a radius r; D.sub.0 is the refractive power of the entire eye at a small aperture (paraxial), i.e., the nominal value of the refractive power of the entire eye; r is the radius of the retina plane; R is the radius of curvature or equivalent radius of curvature of the retina.

(71) Under the above conditions, the distribution of the refractive power of the entire eye on the retina is shown as curve C in FIG. 9. Through the aspheric design, the difference between the refractive power at the edge of the lens and the refractive power at the center of the lens meets the above requirements.

(72) According to the obtained conditions that the refractive power distribution meets, a vision correction lens is made using the aspheric design method such that the refractive power of the vision correction lens has a myopic defocus distribution at different apertures, i.e., the refractive power increases as the aperture increases (as shown in FIG. 2).

(73) The amount of peripheral defocus of a naked human eye (ΔD1) may be measured by an ophthalmic test apparatus (such as OCT, corneal topographer, wavefront aberrometer and the like). When the amount of peripheral defocus provided by the vision correction lens (ΔD2) plus the amount of peripheral defocus of the naked human eye (ΔD1) is greater than or equal to 0, the human eye forms myopic peripheral defocus.

(74) A trial lens of a known diopter and a known refractive power distribution may be worn on the human eye. The amount of peripheral defocus of the human eye with a lens (ΔD3) is examined when the lens is worn. The amount of peripheral defocus of the human eye with a lens (ΔD3) may be measured by an ophthalmic test apparatus. When the amount of peripheral defocus of the human eye with a lens (ΔD3) is greater than 0, it indicates that the amount of defocus of the trial lens already meets the conditions for the human eye to have myopic peripheral defocus, and a vision correction lens may be made accordingly. When the amount of peripheral defocus of the human eye with a lens (ΔD3) is less than or equal to 0, it indicates that the amount of defocus of the lens still puts the human eye in a state of hyperopic peripheral defocus, and the amount of defocus of the lens needs to be increased in order for the human eye to achieve myopic peripheral defocus.

(75) The amount of peripheral defocus of the lens may be increased or decreased according to the patient's own physiological condition and requirements for the extent of myopia control, to achieve custom vision correction.

(76) According to the refractive power distribution plan obtained in step (2), a vision correction lens is made using the aspheric design method such that the refractive power of the vision correction lens has a myopic defocus distribution at different apertures, i.e., the refractive power increases as the aperture increases. The expression of the aspheric surface (as shown in FIG. 3, D is the spherical surface curve, and E is the aspheric surface curve) is:

(77) $Z (y) = \frac{{cy}^{2}}{1 + \sqrt{1 - (1 + Q) c^{2} y^{2}}} + {.Math.}_{i = 2}^{5} A_{2 i} • y^{2 i}$
wherein Z(y) is an expression of the curve of the aspheric surface of the vision correction lens on the plane YZ, c is the reciprocal of the radius of curvature of the base spherical surface of the optical portion, y is the vertical distance from any point on the curve to the abscissa axis (Z), Q is aspheric coefficient, A.sub.2 is aspheric high-order term coefficient, and the points on the aspheric surface are obtained from the curve through rotationally symmetric variation about the abscissa axis (Z).

(78) Through adjustment of the Q value and aspheric coefficients of the vision correction lens, the surface of the vision correction lens exhibits different equivalent curvatures in different radial portions, and the equivalent curvature changes uniformly and continuously throughout the optical zone, so that the vision correction lens has, at different apertures, a refractive power adapted to the refractive power distribution of myopic defocus, with the refractive power in the peripheral region being greater than the refractive power in the central region.

(79) It further comprises a method for controlling the shape of an aspheric surface. The method is described by the scale factor η of equivalent curvature radii (as shown in FIG. 4).

(80) $η_{mn} = \frac{r_{m}}{r_{n}}$

(81) η is the ratio of r at different apertures d.sub.m and d.sub.n, wherein m>n.

(82) For a spherical surface, η=1; for an aspheric surface which is flatter in the periphery than in the center, η>1; for an aspheric surface which is steeper in the periphery than in the center, η<1. The equivalent radius of curvature of the aspheric surface at each aperture is designed through control of the scale factor of the equivalent radii of curvature, thereby enabling the refractive power distribution of the lens to meet the requirements of myopic peripheral defocus.

(83) It is expressed using the difference in refractive power of the lens at different apertures in the air.
ΔD.sub.m,n=D.sub.m−D.sub.n

(84) It represents the difference between the refractive power of the lens at an aperture of m and at an aperture of n, wherein m>n.

(85) The present invention also provides an aspheric vision correction lens, which includes a vision correction lens worn outside the eye, an orthokeratology lens and an intraocular lens. The aspheric vision correction lens is made using the method for preparing an aspheric vision correction lens of the present invention.

(86) The present invention also provides a diagnosis and treatment method that utilizes myopic peripheral defocus to control and retard myopia growth. The diagnosis and treatment method is realized by using an aspheric vision correction lens prepared in the method for preparing an aspheric vision correction lens of the present invention.

Example 3

(87) In this example, the vision correction lens is a vision correction lens worn outside the eye (such as frame glasses).

(88) As shown in FIG. 10, in this example, in addition to the existing fitting methods of frame glasses, RGP, it further comprises a method for preparing an aspheric vision correction lens with controllable peripheral defocus of the present invention, which comprises the following steps:

(89) (1) calculating and determining the conditions required for the formation of myopic defocus of a human eye by examining the shape of the retina of the human eye, the amount of peripheral defocus of the naked human eye or the amount of peripheral defocus of the human eye with a lens;

(90) (2) formulating a plan of distribution of the refractive power of the vision correction lens varying with the aperture, according to the conditions obtained for myopic defocus; and

(91) (3) manufacturing a vision correction lens according to the obtained plan of distribution of the refractive power of the vision correction lens such that after the refractive power of the vision correction lens is added to the human eye, the distribution of the refractive power of the entire eye on the retina is greater in the peripheral region of the retina than in the central region, and falls in front of the retina, to form myopic defocus.

(92) The rest of the contents are the same as above, so it is not repeated here.

Example 4

(93) In this example, the vision correction lens is an orthokeratology lens.

(94) As shown in FIG. 11, in this example, the basic design method of the orthokeratology lens is the same as the existing method, but the surface shape of the base curve zone is determined by the curvature of the retina. The refractive power distribution required by the retina of the human eye is calculated according to the curvature of the retina to ensure that the trend of increase of the refractive power of the human eye along with the increase of the aperture is greater than the curvature of the retina to form hyperopic peripheral defocus, thereby preventing increase of the axial length of the human eye and controlling myopia growth. The surface shape of the inner surface (base curve zone) of the orthokeratology lens is designed according to the distribution of refractive power of the human eye. Since the principle of the orthokeratology lens is that after it is worn on the human eye, the shape of the cornea changes into the shape of the base curve zone of the orthokeratology lens. Therefore, the surface shape of the base curve zone of the orthokeratology lens is the surface shape of the cornea realizing the optical function.

(95) Calculation of the refractive power distribution required by the retina of the human eye according to the curvature of the retina uses the method for preparing an aspheric vision correction lens with controllable peripheral defocus of the present invention. It comprises the steps of:

(96) (1) calculating and determining the conditions required for the formation of myopic defocus of a human eye by examining the shape of the retina of the human eye, the amount of peripheral defocus of the naked human eye or the amount of peripheral defocus of the human eye with a lens;

(97) (2) formulating a plan of distribution of the refractive power of the vision correction lens varying with the aperture, according to the conditions obtained for myopic defocus; and

(98) (3) manufacturing a vision correction lens according to the obtained plan of distribution of the refractive power of the vision correction lens such that after the refractive power of the vision correction lens is added to the human eye, the distribution of the refractive power of the entire eye on the retina is greater in the peripheral region of the retina than in the central region, and falls in front of the retina, to form myopic defocus.

(99) The rest of the contents are the same as above, so it is not repeated here.

Example 5

(100) In this example, the vision correction lens is an intraocular lens.

(101) An intraocular lens mainly refers to a phakic intraocular lens (PIOL) for myopia refraction. PIOL is a negative-power lens implanted surgically between the cornea and lens of the human eye to correct refractive error of the human eye.

(102) Intraocular lenses are divided into the anterior chamber type and the posterior chamber type according to the implantation position. The posterior surface of the anterior chamber type PIOL is generally relatively flat and the anterior surface plays a major role in refraction. The anterior surface of the posterior chamber type PIOL is generally relatively flat, and the posterior surface plays a major role in refraction. They represent two extreme and typical directions of design of negative lenses.

(103) Likewise, the method for preparing an aspheric vision correction lens with controllable peripheral defocus of the present invention comprises the steps of:

(104) (1) calculating and determining the conditions required for the formation of myopic defocus of a human eye by examining the shape of the retina of the human eye, the amount of peripheral defocus of the naked human eye or the amount of peripheral defocus of the human eye with a lens;

(105) (2) formulating a plan of distribution of the refractive power of the vision correction lens varying with the aperture, according to the conditions obtained for myopic defocus; and

(106) (3) manufacturing a vision correction lens according to the obtained plan of distribution of the refractive power of the vision correction lens such that after the refractive power of the vision correction lens is added to the human eye, the distribution of the refractive power of the entire eye on the retina is greater in the peripheral region of the retina than in the central region, and falls in front of the retina, to form myopic defocus.

(107) Through aspheric surface design, an aspheric surface is used to control the surface shape and curvature radius of the optical zone of the lens, such that the radius of curvature changes uniformly at different apertures, the refractive power in the periphery is greater than in the center, and the refractive power distribution has a distribution state of uniform change and hyperopic peripheral defocus, to control myopia growth of the myopic patient.

(108) It will be appreciated by those skilled in the art of lens that the object of the present invention may also be achieved using different combinations of aspheric coefficients in the aspheric surface formula.

(109) On the basis of the design concept of the present invention, those skilled in the art may also conceive achieving hyperopic peripheral defocus of the human eye using the peripheral defocus control idea and diagnosis and treatment method contrary to those in the present invention, so as to treat hyperopia by actively facilitating increase of the axial length of the human eye.

(110) As shown in FIG. 14, an orthokeratology lens according to one aspect of the present invention comprises a lens 100. The base curve zone 101 (the optical zone of the surface in contract with the cornea) of the lens 100 is an aspheric surface. The absolute value of the equivalent radius of curvature in the periphery of the base curve zone 101 of the lens 100 is less than the absolute value of the radius of curvature in the center of the base curve zone 101 of the lens 100.

(111) As shown in FIG. 3, the expression of the aspheric surface of the base curve zone 101 of the lens 100 is:

(112) $Z (y) = \frac{{cy}^{2}}{1 + \sqrt{1 - (1 + Q) c^{2} y^{2}}} + {.Math.}_{i = 2}^{5} A_{2 i} • y^{2 i}$
wherein c is the reciprocal of the radius of curvature of the base spherical surface of the optical portion, y is the vertical distance from any point on the curve to the abscissa axis (Z), Q is aspheric coefficient, A.sub.2 is aspheric high-order term coefficient, and the aspheric surface is obtained from the aspheric surface curve through rotationally symmetric variation about the abscissa axis (Z).

(113) As shown in FIG. 4, the shape of the aspheric surface of the base curve zone 101 of the lens 100 is defined by the scale factor η of equivalent radii of curvature. The scale factor η of equivalent radii of curvature of the aspheric surface is less than 1.

(114) Scale factor η is the ratio of r of the lens at different diameters d.sub.m and d.sub.n, wherein m>n,

(115) 0 $η_{mn} = \frac{r_{m}}{r_{n}};$

(116) For a spherical surface, η=1; for an aspheric surface flatter in the periphery than in the center, η>1; and for an aspheric surface steeper in the periphery than in the center, η<1.

(117) The radius of curvature of an aspheric surface cannot be represented by the radius of curvature of a conventional spherical surface, but by an equivalent radius of curvature. The equivalent radius of curvature of the base curve zone 101 of the lens 100 is calculated in the following way,

(118) $r_{m} = \frac{{(\frac{d_{m}}{2})}^{2} + h_{m}^{2}}{2 h_{m}} = \frac{{(d_{m})}^{2} + 4 h_{m}^{2}}{8 h_{m}}$
wherein d.sub.m is the measured aperture; M is the point at the aperture d.sub.m; h.sub.m is the sagittal height of point M, i.e., the difference in height between point M and the vertex of the aspheric surface; and r.sub.m is the equivalent radius of curvature at point M.

(119) Preferably, the scale factor η.sub.53 of the equivalent radii of curvature of the aspheric surface of the base curve zone 101 of the lens 100 at the 5 mm aperture and the 3 mm aperture is greater than or equal to 0.67 and less than 1.

(120) More preferably, the scale factor η.sub.53 of the equivalent radii of curvature of the aspheric surface of the base curve zone 101 of the lens 100 at the 5 mm aperture and the 3 mm aperture is greater than or equal to 0.67 and less than or equal to 0.998.

(121) Still more preferably, the scale factor η.sub.53 of the equivalent radii of curvature of the aspheric surface of the base curve zone 101 of the lens 100 at the 5 mm aperture and the 3 mm aperture is greater than or equal to 0.67 and less than or equal to 0.991.

(122) For specific examples of the present invention, please see Table 3 and Table 4, in which Q, A4, A6, and A8 are aspheric coefficients; η.sub.53 is the scale factor of the equivalent radii of curvature of the lens at the 5 mm aperture and the 3 mm aperture.

(123) TABLE-US-00003 TABLE 3 Embodiments of Surface Shape of Base Curve Zone of Orthokeratology Lens Radius of Radius of curvature Q η.sub.53 curvature Q η.sub.53 9.643 0.2 0.998 5.000 2.5 0.820 9.643 0.5 0.994 10.000 5.0 0.940 9.643 1.0 0.989 7.000 0.5 0.989 6.136 0.2 0.994 7.000 3.0 0.921 6.136 1.0 0.969 8.000 3.0 0.944 6.136 3.0 0.885 5.000 0.2 0.991 6.136 5.0 0.665 5.000 0.5 0.976 6.136 4.0 0.818 5.000 0.7 0.966 5.000 1.0 0.949 5.000 2.0 0.876 5.000 1.2 0.937 5.000 2.5 0.820 5.000 1.5 0.917 5.000 2.9 0.741

(124) TABLE-US-00004 TABLE 4 Embodiments of Surface Shape of Base Curve Zone of Orthokeratology Lens Radius of curva- ture Q A4 A6 A8 η.sub.53 5.946 9.400E−02 1.604E−04 1.695E−06 2.829E−07 0.990 4.935 1.385E−01 4.806E−04 4.146E−06 9.006E−07 0.978 4.934 1.385E−01 4.702E−04 4.087E−06 8.892E−07 0.978 4.939 1.618E−01 6.567E−04 1.322E−05 8.648E−07 0.970 5.068 8.048E−03 6.610E−05 6.408E−07 2.590E−09 0.997

(125) It would come readily to those skilled in the art that different combinations of aspheric coefficients may be used to achieve an aspheric surface structure the same as that in the present invention.

(126) On the basis of the present invention's concept of controlling myopic growth by myopic peripheral defocus and aspheric surface design of the lens, those skilled in the art may also conceive making, through modified control of the base curve zone of the lens contrary to that in the present invention, the absolute value of the equivalent radius of curvature of the lens at a larger aperture greater than that at a smaller aperture, to achieve hyperopic peripheral defocus of the human eye to thereby treat hyperopia by actively facilitating increase of the axial length of the human eye.

(127) With reference to FIGS. 15, 16, 17 and 18, an intraocular lens according to one aspect of the present invention comprises an optical zone 100 of the lens and a support haptic 110. At least one of the anterior surface 101 or the posterior surface 102 of the optical zone 100 of the lens is aspheric. The aspheric surface makes the absolute value of the equivalent radius of curvature in the periphery of the optical zone 100 of the lens greater than the absolute value of the radius of curvature in the center of the optical zone 100 of the lens.

(128) As shown in FIGS. 2 and 19, the lens changes uniformly in the direction of the aperture according to the set refractive power peripheral defocus amount. The refractive power of the lens increases as the aperture increases, and the absolute value of the refractive power decreases as the aperture increases. The refractive power of the lens in the aqueous humor is smaller than or equal to 0D.

(129) In FIG. 19, A is a curve of distribution of the refractive power of a spherical lens, B is a curve of distribution of the refractive power of the existing aspheric lens, and C is a curve of distribution of the refractive power of an intraocular lens of the present invention.

(130) With reference to FIGS. 3 and 20, the expression of the aspheric surface of the optical zone 100 of the lens is:

(131) $Z (y) = \frac{{cy}^{2}}{1 + \sqrt{1 - (1 + Q) c^{2} y^{2}}} + {.Math.}_{i = 2}^{5} A_{2 i} • y^{2 i}$
wherein c is the reciprocal of the radius of curvature of the base spherical surface of the optical portion, y is the vertical distance from any point on the curve to the abscissa axis (Z), Q is aspheric coefficient, A.sub.2i is aspheric high-order term coefficient, and the aspheric surface is obtained from the aspheric surface curve through rotationally symmetric variation about the abscissa axis (Z).

(132) In FIG. 20, A′ is a spherical surface base curve, B′ is an existing aspheric surface base curve, and C′ is an aspheric surface base curve of the present invention.

(133) As shown in FIG. 4, the shape of the aspheric surface of the optical zone 100 of the lens is defined by the scale factor η of equivalent radii of curvature. The scale factor η of equivalent radii of curvature of the aspheric surface is greater than 1.

(134) Scale factor η is the ratio of r of the lens at different apertures d.sub.m and d.sub.n, wherein m>n,

(135) $η_{mn} = \frac{r_{m}}{r_{n}};$

(136) For a spherical surface, η=1; for an aspheric surface flatter in the periphery than in the center, η>1; and for an aspheric surface steeper in the periphery than in the center, η<1.

(137) The equivalent radius of curvature of the optical zone 100 of the lens is calculated in the following way,

(138) $r_{m} = \frac{{(\frac{d_{m}}{2})}^{2} + h_{m}^{2}}{2 h_{m}} = \frac{{(d_{m})}^{2} + 4 h_{m}^{2}}{8 h_{m}}$
wherein d.sub.m is the measured aperture; M is the point at the aperture d.sub.m; h.sub.m is the sagittal height of point M, i.e., the difference in height between point M and the vertex of the aspheric surface; and r.sub.m is the equivalent radius of curvature at point M.

(139) Preferably, the scale factor η.sub.43 of the equivalent radii of curvature of the aspheric surface of the optical zone of the lens at the 4 mm aperture and the 3 mm aperture is greater than or equal to 1.005.

(140) Preferably, the scale factor η.sub.43 of the equivalent radii of curvature of the aspheric surface of the optical zone of the lens at the 4 mm aperture and the 3 mm aperture is greater than or equal to 1.002 and less than or equal to 1.09.

(141) Preferably, the scale factor η.sub.43 of the equivalent radii of curvature of the aspheric surface of the optical zone of the lens at the 4 mm aperture and the 3 mm aperture is greater than or equal to 1.01 and less than or equal to 1.09.

(142) For several examples of the present invention, please see Table 5. In the table, for the examples involving parameters Rp, Qp, A4, A6 and A8, the aspheric surface is on the posterior surface of the lens, wherein Rp is the radius of curvature of the base spherical surface of the posterior surface, and Qp, A4, A6, A8 are aspheric coefficients. For the examples involving parameters Ra, Qa, A4, A6 and A8, the aspheric surface is on the anterior surface of the lens, wherein Ra is the radius of curvature of the base spherical surface of the anterior surface, and Qa, A4, A6, A8 are aspheric coefficients. η.sub.43 is the scale factor of the equivalent radii of curvature of the lens at the 4 mm aperture and the 3 mm aperture.

(143) TABLE-US-00005 TABLE 5 Examples Refractive index Rp Qp A4 A6 A8 η.sub.43 1.45 5.516 −0.218 −6.089E−04 −4.574E−04 3.574E−05 1.048 1.48 6.838 −3.263 −5.330E−04 −1.525E−06 6.005E−08 1.041 1.50 7.811 −3.176 −5.774E−04 1.016E−06 −1.214E−08 1.038 1.55 10.700 −3.263 −5.330E−04 −1.525E−06 6.005E−08 1.034 1.60 13.200 −3.263 −5.330E−04 −1.525E−06 6.005E−08 1.035 1.70 18.200 −3.263 −5.330E−04 −1.525E−06 6.005E−08 1.042 1.45 5.700 −5.000 0 0 0 1.053 1.45 5.700 −10.000 0 0 0 1.086 1.45 5.583 −0.302 −6.258E−04 −5.129E−06 −1.221E−07 1.016 1.50 8.116 −0.525 −1.65E−04 −9.82E−07 1.96E−08 1.008 1.55 10.634 −0.530 −7.84E−05 −6.75E−07 1.93E−08 1.005 1.70 18.170 −0.739 −7.92E−06 −4.60E−07 1.44E−08 1.002 Refractive index Ra Qa A4 A6 A8 η.sub.43 1.45 −5.670 2.891 −4.209E−05 1.460E−03 −1.193E−04 1.037

(144) In light of the object of the present invention, the absolute value of the equivalent radius of curvature of the aspheric surface of the optical zone 100 of the lens at a larger aperture is greater than that at a smaller aperture. The aspheric surface may be located on either of the anterior surface and the posterior surface, or both surfaces are aspheric surfaces.

(145) It would come to those skilled in the art that the object of the present invention may also be achieved by using different combinations of the aspheric coefficients in the aspheric surface formula, and that the shape of the support haptics 110 of the lens may be of any shape that can perform the same function.

(146) On the basis of the present invention's concept of controlling myopic growth by myopic peripheral defocus and aspheric surface design of the lens, those skilled in the art may also conceive making, through contrary modified control of the lens, the absolute value of the refractive power of the lens at a larger aperture greater than that at a smaller aperture, to achieve hyperopic peripheral defocus of the human eye to thereby treat hyperopia by actively facilitating increase of the axial length of the human eye.

(147) The basic principles, main features and advantages of the present invention have been shown and described above. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments, and the above embodiments and description only illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will also have various changes and modifications which fall within the scope of protection of the present invention. The scope of protection of the present invention is defined by the appended claims and the equivalents thereof.

Vision correction lens and method for preparation of the same

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G02C7/027

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A61B3/1005

HUMAN NECESSITIES

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A61F2/1602

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G02C2202/24

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G02C7/049

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G02C7/04

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G02C7/028

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G02C7/047

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G02C7/02

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B29D11/00038

PERFORMING OPERATIONS; TRANSPORTING

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B29D11/00951

PERFORMING OPERATIONS; TRANSPORTING

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A61F2/164

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G02C7/063

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G01M11/0228

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B29D11/00

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A61B3/10

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Abstract

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Description