LENS SURFACE WITH COMBINED DIFFRACTIVE, TORIC, AND ASPHERIC COMPONENTS
In one aspect, the present invention provides an intraocular lens (IOL) that includes an optic comprising an anterior surface, a posterior surface, and a plurality of diffractive zones disposed on one of those surfaces. The surface having the diffractive zones has a profile characterized by a combination of aspheric and toric components.
1 . An intraocular lens (IOL), comprising
an optic comprising an anterior surface and a posterior surface,
a plurality of diffractive zones disposed on one of said surfaces,
wherein said surface having the diffractive zones exhibits a base profile characterized by a combination of asphericity and toricity.
2 . The IOL of claim 1 , wherein said optic provides a far focus and a near focus.
3 . The IOL of claim 2 , wherein said far focus provides an optical power in a range of about 16 D to about 32 D.
4 . The IOL of claim 3 , wherein said near focus provides an add power in a range of about 1 D to about 6 D.
5 . The IOL of claim 1 , wherein said anterior surface comprises said diffractive structures and said asphericity and toricity.
6 . The IOL of claim 1 , wherein a profile of said surface is characterized by the following relation:
sag(R avrg ,r ,θ)=diffractive(R ave ,r )+toric(R ave ,r ,θ)+asph(R ave ,r ),
wherein,
sag represents a sag of the surface along an optical axis of the optic at a radial distance r from a center of the surface at a meridian angle θ, where R avrg represents a base radius of curvature of average meridian, and
wherein,
diffractive(R avrg ,r )= z rad −√{square root over (R rad 2 −r 2 )},
wherein,
z rad and R rad denote, respectively, a radius of curvature of a diffractive zone extending through the radial distance r and an axial location of a curvature center of that zone, and
wherein,
toric
(
R
avrg
,
r
,
θ
)
=
(
c
x
cos
2
θ
+
c
y
sin
2
θ
)
r
2
1
+
1
-
(
1
+
k
x
)
c
x
2
r
2
cos
θ
2
-
(
1
+
k
y
)
c
y
r
2
sin
2
θ
,
wherein,
c x and c y represent toric curvatures along two principal meridians of the surface and k x and k y represent toric conic constants along the two principal meridians, and
wherein,
asph
(
R
avrg
,
r
)
=
cr
2
1
+
1
-
(
1
+
k
)
c
2
r
2
,
and
wherein
c
=
1
R
avrg
,
and
wherein k represents a spherical conic constant.
7 . The IOL of claim 6 , wherein z rad is defined in a Cartesian coordinate (x,y,z), where z is along the optical axis, in accordance with the following relation:
z
rad
=
x
in
2
+
z
in
2
-
x
out
2
-
z
out
2
2
(
z
in
-
z
out
)
,
wherein x in and z in represent, respectively, x and z coordinates of an inner boundary of the diffractive zone and x out and z out represent, respectively, x and z coordinates of an outer boundary of the diffractive zone.
8 . The IOL of claim 7 , wherein R rad is defined in the Cartesian coordinates in accordance with the following relation:
R rad =√{square root over (( z in −z rad ) 2 +x in 2 )}.
9 . The IOL of claim 8 , wherein a magnitude of R avrg is in a range of about 12 mm to about 120 mm.
10 . The IOL of claim 9 , wherein a magnitude of c x is in a range of about 0.008 mm −1 to about 0.08 mm −1 and a magnitude of c y is in a range of about 0.008 mm −1 about 0.08 mm −1 .
11 . The IOL of claim 10 , wherein kx is in a range of about −3000 to about −12 and k y is in a range of about −3000 to about −12.
12 . The IOL of claim 11 , wherein k is in range of about −3000 to about −12.
13 . The IOL of claim 1 , wherein said diffractive zones comprise a plurality of diffractive structures separated from one another by a plurality of step heights.
14 . The IOL of claim 13 , wherein a radius of curvature of a diffractive zone along a meridian characterized by an angle θ (R d θ ) and a radius of curvature of a base profile associated with that diffractive zone (R b θ ) are related in accordance with the following relation:
(
n
1
-
n
2
)
(
1
R
d
θ
-
1
R
b
θ
)
=
Constant
.
15 . The IOL of claim 14 , wherein said Constant is in a range of about 0 D to about 4 D.
16 . The IOL of claim 1 , wherein said anterior surface includes said diffractive zones.
17 . The IOL of claim 16 , wherein said posterior surface exhibits a spherical profile.
18 . A diffractive ophthalmic lens, comprising
an optic having an anterior surface and a posterior surface,
wherein at least one of said surfaces exhibits a profile characterized by a combination of diffractive, aspheric and toric components.
19 . The ophthalmic lens of claim 18 , wherein said lens provides a far-focus optical power in a range of about 16 D to about 32 D.
20 . The ophthalmic lens of claim 19 , wherein said lens provides a near-focus power characterized by an add power in a range of about 1 D to about 6 D.