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 −6 diopters, 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 one of the first and second central optical zones of each lens in the series is a spherical surface whereas the other is an aspherical surface, wherein the aspherical surface of each lens in the series has a design that, in combination with the spherical surface provides an optical 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 lenses of claim 1 , wherein the second central optical zones of all the lens in the series are substantially identical to each other.
3. The series of contact lenses of claim 2 , wherein the second central optical zone of each lens in the series is a spherical surface.
4. The series of contact lenses of claim 1 , wherein the aspherical surface is 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.
5. The series of contact lenses of claim 4 , wherein each lens in the seires has a substantially constant spherical aberration profile.
6. The series of contact lenses of claim 5 , wherein the spherical aberration at 6 mm diameter is from about 0.9 diopter to about 1.4 diopters more negative than the spherical aberration at 4 mm diameter.
7. The series of contact lenses of claim 5 , wherein the spherical aberration profile is substantially identical to the spherical aberration profile of a spherical lens having a targeted optical power of −6 diopters.