Intra ocular lens
The invention relates to a intra lens ( 1 ) comprising a posterior surface and an anterior surface, said posterior surface having a curvature which is optimized for providing a minimal spherical aberration, wherein said curvature is optimized using the posterior chamber depth of an eye in which the IOL is to be inserted.
1. An intra ocular lens (IOL) comprising:
an anterior surface and a posterior surface, said posterior surface having a curvature defined as or equivalent to
z
=
r
2
/
R
2
1
+
1
-
(
1
+
k
)
r
2
/
R
2
,
with
k
=
n
2
R
3
n
1
2
(
1
R
-
1
PCD
)
2
(
n
1
+
n
2
PCD
-
n
2
R
)
+
8
R
3
n
1
-
n
2
σ
,
in which equations the used parameters are
k=−e 2 conic constant,
R Radius of curvature,
r radial distance from optical axis,
z height or sagitta of refracting surface,
n 1 refractive index of the material of the IOL,
n 2 refractive index of the vitreous body of the eye,
PCD Posterior chamber depth, and
σ Coefficient specifying additional spherical aberration
to have a specified amount of spherical aberration.
2. The IOL according to claim 1 , wherein the conic constant is given by
k
=
n
2
R
3
n
1
2
(
1
R
-
1
PCD
)
2
(
n
1
+
n
2
PCD
-
n
2
R
)
to have zero spherical aberration.
3. The IOL of claim 1 , wherein said curvature is optimised by ray-tracing using the PCD as a parameter.
4. The IOL of claim 1 , wherein the PCD is obtained using a biometric measurement on an eye from which values relating to the size of the measured eye can be derived.
5. The IOL of claim 1 , wherein the PCD is obtained using a predetermined relation between PCD values determined for persons in a population and calculated power for the IOL for the persons of that population.