Contact lenses with off-center sphere surface
View Patent ↗The present invention provides a contact lens comprising a convex surface and a concave surface, one or both of the surfaces comprising: a) a central optical zone that is an aspherical sub-surface; b) a transition zone that is adjacent to said central optical zone, wherein and is a rotationally symmetric off-center sphere sub-surface; and c) a peripheral zone that comprises one or more sphere sub-surfaces, wherein all sub-surfaces are tangent to each other. By having a transition zone of the present invention, flexion points at the junction of optical zone with peripheral zone can be eliminated. The present invention also provides a method for producing a contact lens of the present invention.
1. A contact lens comprising a convex surface and a concave surface, one or both of the surfaces comprising:
(a) an apex;
(b) an axis passing through the apex;
(c) a central optical zone that is an aspherical sub-surface described by an aspherical function form y opz (x);
(d) a transition zone that is adjacent to and surrounds said central optical zone, wherein said transition zone is a rotationally symmetric off-center sphere sub-surface characterized by having a curvature radius r a the center C(x c ,y c ) of which is not located in the axis, wherein said curvature radius (r a ) is defined by a functional form (2)
r
a
=
{
1
+
[
y
opz
′
(
x
a
)
]
2
}
3
/
2
y
opz
′′
(
x
a
)
,
(
2
)
wherein the center C(x c ,y c ) of the curvature radius r a is given by formula (3) and (4)
x
c
=
x
a
-
y
opz
′
(
x
a
)
·
{
1
+
[
y
opz
′
(
x
a
)
]
2
}
y
opz
′′
(
x
a
)
(
3
)
y
c
=
y
a
-
{
1
+
[
y
opz
′
(
x
a
)
]
2
}
y
opz
′′
(
x
a
)
(
4
)
wherein y′ opz (X a ) is the 1 st derivative of the aspherical function form at a junction point A(x a ,y a ) of the transition zone with the central optical zone, y″ opz (x a ) is the 2 nd derivative of the aspherical function form at the junction point A(x a ,y a ); and
(e) a peripheral zone that comprises one or more sphere sub-surfaces, wherein all sub-surfaces are tangent to each other.
2. A contact lens of claim 1 , further comprising a blend zone between said transition zone and said peripheral zone.
3. A contact lens of claim 1 , wherein said aspherical function form is equation (1)
y
opz
=
x
2
r
(
1
+
1
-
1
+
κ
r
0
2
x
2
)
or
y
opz
=
a
0
+
a
1
x
+
a
2
x
2
+
…
+
a
n
x
n
(
1
)
wherein r 0 is the radius at the apex of the aspherical sub-surface, κ is a conic constant, a 0 , . . . , a n are coefficient constants.
4. A contact lens of claim 1 , wherein said convex surface comprises said central optical zone, said transition zone, and said peripheral zone.
5. A contact lens of claim 1 , wherein said concave surface comprises said central optical zone, said transition zone, and said peripheral zone.
6. A contact lens of claim 1 , wherein said contact lens is a soft contact lens.
7. A contact lens of claim 1 , wherein said peripheral zone comprises multiple sphere sub-surfaces with fillet between two neighboring sphere sub-surfaces.
8. A method of producing a contact lens, comprising the steps of providing a convex surface and a concave surface, one or both of the surfaces comprising:
(a) an apex;
(b) an axis passing through the apex;
(c) a central optical zone that is an aspherical sub-surface described by an aspherical function form form y opz (x);
(d) a transition zone that is adjacent to and surrounds said central optical zone, wherein said transition zone is a rotationally symmetric off-center sphere sub-surface characterized by having a curvature radius r a , the center C(x c ,y c ) of which is not located in the axis, wherein said curvature radius (r a ) is defined by a functional form (2)
r
a
=
{
1
+
[
y
opz
′
(
x
a
)
]
2
}
3
/
2
y
opz
′′
(
x
a
)
,
(
2
)
wherein the center C(x c ,y c ) of the curvature radius r a is given by formula (3) and (4)
x
c
=
x
a
-
y
opz
′
(
x
a
)
·
{
1
+
[
y
opz
′
(
x
a
)
]
2
}
y
opz
′′
(
x
a
)
(
3
)
y
c
=
y
a
+
{
1
+
[
y
opz
′
(
x
a
)
]
2
}
y
opz
′′
(
x
a
)
(
4
)
wherein y′ opz (x a ) is the 1 st derivative of the aspherical function form at a junction point A(x a ,y a ) of the transition zone with the central optical zone, y″ opz (x a ) is the 2 nd derivative of the aspherical function form at the junction point A(x a ,y a ); and
(e) a peripheral zone that comprises one or more sphere sub-surfaces, wherein all sub-surfaces are tangent to each other.
9. A method of claim 8 , wherein said aspherical function form is equation (1)
y
opz
=
x
2
r
(
1
+
1
-
1
+
κ
r
0
2
x
2
)
or
y
opz
=
a
0
+
a
1
x
+
a
2
x
2
+
…
+
a
n
x
n
(
1
)
wherein r 0 is the radius at the apex of the aspherical sub-surface, κ is a conic constant, a0, . . . , an are coefficient constants.
10. A method of claim 8 , wherein said convex surface comprises said central optical zone, said transition zone, and said peripheral zone.
11. A method of claim 8 , wherein said concave surface comprises said central optical zone, said transition zone, and said peripheral zone.
12. A method of claim 8 , wherein said contact lens is a soft contact lens.
13. A series of contact lenses comprising contact lenses having different power corrections, wherein each contact lens in the series comprises a convex surface and a concave surface, one or both of the surfaces comprising:
(a) an apex;
(b) an axis passing through the apex;
(c) a central optical zone that is an aspherical sub-surface described by an aspherical function form form y opz (x);
(d) a transition zone that is adjacent to and surrounds said central optical zone, wherein said transition zone is a rotationally symmetric off-center sphere sub-surface characterized by having a curvature radius r a the center C(x c ,y c ) of which is not located in the axis, wherein said curvature radius (r a ) is defined by a functional form (2)
r
a
=
{
1
+
[
y
opz
′
(
x
a
)
]
2
}
3
/
2
y
opz
′′
(
x
a
)
,
(
2
)
wherein the center C(x c ,y c ) of the curvature radius r a is given by formula (3) and (4)
x
c
=
x
a
-
y
opz
′
(
x
a
)
·
{
1
+
[
y
opz
′
(
x
a
)
]
2
}
y
opz
′′
(
x
a
)
(
3
)
y
c
=
y
a
+
{
1
+
[
y
opz
′
(
x
a
)
]
2
}
y
opz
′′
(
x
a
)
(
4
)
wherein y′ opz (x a ) is the 1 st derivative of the aspherical function form at a junction point A(x a ,y a ) of the transition zone with the central optical zone, y″ opz (x a ) is the 2 nd derivative of the aspherical function form at the junction point A(x a ,y a ); and
(e) a peripheral zone that comprises one or more sphere sub-surfaces, wherein all sub-surfaces are tangent to each other.
14. A series of contact lenses of claim 13 , wherein said aspherical function form is equation (1)
y
opz
=
x
2
r
(
1
+
1
-
1
+
κ
r
0
2
x
2
)
or
y
opz
=
a
0
+
a
1
x
+
a
2
x
2
+
…
+
a
n
x
n
(
1
)
wherein r 0 is the radius at the apex of the aspherical sub-surface, κ is a conic constant, a 0 , . . . , a n are coefficient constants.
15. A series of contact lenses of claim 13 , wherein said surface is a convex surface.
16. A series of contact lenses of claim 13 , wherein said surface is a concave surface.
17. A series of contact lenses of claim 13 , wherein said convex surface comprises said central optical zone, said transition zone, and said peripheral zone.