Series of aspherical contact lenses
View Patent ↗The present invention provides a series of aspherical contact lenses, each lens having a first central optical zone on its anterior surface and a second central optical zone on its posterior surface. Both central optical zones are aspherical surfaces. The first central optical zone is designed to have a surface which provides a target optical power and an optical power profile selected from the group consisting of (1) a substantially constant optical power profile, (2) a power profile mimicking the optical power profile of a spherical lens with an identical targeted optical power, and (3) a power profile in which lens spherical aberration at 6 mm diameter is from about 0.65 diopter to about 1.8 diopters more negative than spherical aberration at 4 mm diameter.
1. A series of contact lenses, each lens in the series having a targeted optical power within the range of −15 diopters to 10 diopters for correcting myopia or hypermetropia, each lens in the series comprising an anterior surface having a first central optical zone and an opposite posterior surface having a second central optical zone, wherein the second central optical zones of all the lens in the series are substantially identical to each other and are aspherical surfaces, wherein the first central optical zone of each lens in the series has an aspherical design that, in combination with the second central optical zone, provides an optical power profile selected from the group consisting of (1) a substantially constant optical power profile, (2) a power profile mimicking the optical power profile of a spherical lens with an identical targeted optical power, and (3) a power profile in which lens spherical aberration at 6 mm diameter is from about 0.65 diopter to about 1.8 diopters more negative than spherical aberration at 4 mm diameter.
2. The series of contact lens of claim 1 , wherein the second central optical zone of the posterior surface is a conic surface defined by eq. (1)
S
1
=
c
1
x
2
1
+
1
-
(
1
+
k
1
)
c
1
2
x
2
(
1
)
in which S 1 is the saggital height, c 1 is the apical curvature (the reciprocal of the apical radius), x is the radial distance from the apex, and k 1 is a conic constant.
3. The series of contact lenses of claim 2 , wherein the first central optical zone of the anterior surface is a surface defined by
S
2
=
c
2
x
2
1
+
1
-
(
1
+
k
2
)
c
2
2
x
2
+
α
1
x
2
+
α
2
x
4
+
α
3
x
6
+
α
4
x
8
+
α
5
x
10
+
α
6
x
12
+
α
7
x
14
(
2
)
in which S 2 is the saggital height, c 2 is the apical curvature (the reciprocal of the apical radius), x is the radial distance from the apex, k 2 is a conic constant, and α 1 to α 7 are the coefficients.
4. The series of contact lenses of claim 3 , wherein each lens in the series having a targeted positive optical power has a substantially constant optical power profile.
5. The series of contact lenses of claim 3 , wherein each lens in the series having a targeted optical power within the range of −1 to −6 has a power profile mimicking the optical power profile of a spherical lens with an identical targeted optical power.
6. The series of contact lenses of claim 3 , wherein each lens in the series having a targeted optical power more negative than −6 diopters has a power profile in which lens spherical aberration at 6 mm diameter is from about 0.65 diopter to about 1.8 diopters more negative than spherical aberration at 4 mm diameter.
7. The series of contact lenses of claim 6 , wherein the spherical aberration at 6 mm diameter is from about 0.9 diopters to about 1.4 diopters more negative than the spherical aberration at 4 mm diameter.
8. The series of contact lenses of claim 3 , wherein each lens in the series having a targeted optical power more negative than −6 diopters has a substantially constant spherical aberration profile.
9. The series of contact lenses of claim 8 , wherein the spherical aberration profile is substantially identical the spherical aberration profile of a spherical lens having a targeted optical power of −6 diopters.
10. The series of contact lenses of claim 3 , each lens in the series having a targeted optical power within a range from −6 diopters to 6 diopters.
11. A method for making a series of contact lenses, comprising the steps of:
i) designing a posterior surface comprising a first central optical zone which is an aspherical surface defined by eq. (1)
S
1
=
c
1
x
2
1
+
1
-
(
1
+
k
1
)
c
1
2
x
2
(
1
)
in which S 1 is the saggital height, c 1 is the apical curvature (the reciprocal of the apical radius), x is the radial distance from the apex, and k 1 is a conic constant;
ii) designing an anterior surface comprising a second central optical zone, wherein the second central optical zone is a surface defined by
S
2
=
c
2
x
2
1
+
1
-
(
1
+
k
2
)
c
2
2
x
2
+
α
1
x
2
+
α
2
x
4
+
α
3
x
6
+
α
4
x
8
+
α
5
x
10
+
α
6
x
12
+
α
7
x
14
(
2
)
in which S 2 is the saggital height, c 2 is the apical curvature (the reciprocal of the apical radius), x is the radial distance from the apex, k 2 is a conic constant, and α 1 to α 7 are the coefficients;
iii) for each lens in the series adjusting one or more of c 2 , k 2 , and α 1 to α 7 while keeping c 1 and k 1 unchanged, so as to provide a targeted optical power within a range from −15 diopters to 10 diopters and an optical power profile selected from the group consisting of (1) a substantially constant optical power profile, (2) a power profile mimicking the optical power profile of a spherical lens with an identical targeted optical power, and (3) a power profile in which lens spherical aberration at 6 mm diameter is from about 0.65 diopter to about 1.8 diopters more negative than spherical aberration at 4 mm diameter; and
iv) producing each lens in the series by lathing or molding.
12. The method of claim 11 , wherein each lens in the series having a targeted positive optical power has a substantially constant optical power profile.
13. The method of claim 11 , wherein each lens in the series having a targeted optical power within the range of −1 to −6 has a power profile mimicking the optical power profile of a spherical lens with identical targeted optical power.
14. The method of claim 11 , wherein each lens in the series having a targeted optical power more negative than −6 diopters has a power profile in which lens spherical aberration at 6 mm diameter is from about 0.65 diopter to about 1.8 diopters more negative than spherical aberration at 4 mm diameter.
15. The method of claim 14 , wherein the spherical aberration at 6 mm diameter is from about 0.9 diopters to about 1.4 diopters more negative than the spherical aberration at 4 mm diameter.
16. The method of claim 11 , wherein each lens in the series having a targeted optical power more negative than −6 diopters has a substantially constant spherical aberration profile.
17. The method of claim 16 , wherein the spherical aberration profile is substantially identical the spherical aberration profile of a spherical lens having a targeted optical power of −6 diopters.
18. The method of claim 11 , each lens in the series having a targeted optical power within a range from −6 diopters to 6 diopters.