Implant and method for altering the refractive properties of the eye

1 . A method of changing the refractive properties of an eye, comprising the steps of

separating the cornea to form a first layer and a second layer, said first layer facing in a posterior direction of the eye and said second layer facing in an anterior direction of the eye, said first and second layers remaining attached at an area at the main optical axis,

inserting an implant between said first and second layers, said implant including a first portion having a first index of refraction and adapted to change the refractive properties of a first portion of the eye, a second portion having a second index of refraction and adapted to change the refractive properties of a second portion of the eye, and a third portion having a substantially arcuate edge adapted to be positioned adjacent the area attached at the main optical axis.

2 . A method according to claim 1 wherein

said implant is substantially ring-shaped and said first portion forms a substantially ring-shaped portion located at the periphery of said implant.

3 . A method according to claim 1 , wherein

said implant is substantially ring-shaped and shaped third portion substantially surrounds said area attached at the main optical axis.

4 . A method according to claim 1 , wherein

said first index of refraction is higher than said second index of refraction.

5 . A method according to claim 1 , wherein

said third portion has a third index of refraction, said third index of refraction being lower than said second index of refraction.

6 . A method according to claim 5 , wherein

said third index of refraction is substantially the same as the corneal index of refraction.

7 . A method according to claim 6 , wherein

said third portion is a transition zone, which flattens the cornea adjacent the area attached at the main optical axis.

8 . A method according to claim 1 , wherein

said step of separating the cornea includes forming a flap in the corneal stroma.

9 . A method according to claim 1 , wherein

said step of separating the cornea includes forming an epithelial flap.

10 . A method according to claim 1 , further comprising the step of

ablating a surface of the cornea overlying the area attached at the main optical axis.

11 . A method according to claim 10 , wherein

said surface overlying the main optical axis is a surface exposed by at least one of a corneal flap and a stromal flap.

12 . An implant for changing the refractive properties of an eye, comprising:

a body adapted to be implanted between layers of the cornea offset from the main optical axis, thereby changing the refractive properties of the eye, the body including

a first portion having a first refractive power and configured to change the refractive properties of a first area of the cornea by changing the corneal curvature thereof; and

a second portion having a second refractive power, said second refractive power configured to change the refractive properties of a second area of the cornea and 4 compensate for error at said second area caused by said first portion.

13 . An implant according to claim 12 , wherein

said first portion is configured to have a first refractive index; and

said second portion is configured to have a second refractive index, said second refractive index being lower than said first index.

14 . An implant according to claim 12 , wherein

said body is substantially ring-shaped and said first portion is a substantially ring-shaped portion located at the periphery of said body portion.

15 . An implant according to claim 13 , wherein

said body further includes a third portion having a third refractive index, said third refractive index being less than said second refractive index and being substantially the same as the refractive index of the cornea.

16 . An implant according to claim 15 , wherein

said third portion is a transition zone configured to flatten a predetermined portion of the cornea.

17 . An implant for changing the refractive properties of an eye, comprising:

a first semi circular body portion adapted to be implanted between layers of the cornea offset from the main optical axis, thereby changing the refractive properties of the eye, the first semi circular body portion including

a first portion having a first refractive power and configured to change the refractive properties of a first area of the cornea by changing the corneal curvature thereof; and

a second portion having a second refractive power, said second refractive power configured to change the refractive properties of a second area of the cornea and compensate for error at said second area caused by said first portion; and

a second semi circular body portion adapted to be implanted between layers of the cornea offset from the main optical axis, thereby changing the refractive properties of the eye, the second semi circular body portion including

a third portion having a third refractive power configured to change the refractive properties of a third area of the cornea by changing the corneal curvature thereof; and

a fourth portion having a fourth refractive power, said fourth refractive power configured to change the refractive properties of a fourth area of the cornea and compensate for error at said second area caused by said third portion.

18 . A method of changing the refractive properties of the an eye, comprising the steps of

separating the cornea to form a first layer and a second layer, said first layer facing in a posterior direction of the eye and said second layer facing in an anterior direction of the eye, said first and second layers remaining attached at an area at the main optical axis,

inserting a first semi-circular implant between said first and second layers, said first implant including a first portion having a first index of refraction and adapted to change the refractive properties of a first portion of the eye, and a second portion having a second index of refraction and adapted to change the refractive properties of a second portion of the eye; and

inserting a second semi-circular implant between said first and second layers, said second implant including a third portion having a third index of refraction and adapted to change the refractive properties of a third portion of the eye, a fourth portion having a fourth index of refraction and adapted to change the refractive properties of a fourth portion of the eye.

19 . A method according to claim 18 , further comprising the step of

positioning the first and second implants such that they are aligned with an astigmatic axis of the eye.

20 . A method according to claim 19 , wherein

the step of separating the cornea to form a first corneal layer and a second corneal layer includes separating the cornea to form a substantially circular flap that is coupled to the cornea at substantially the center thereof and disconnected at substantially all of the periphery thereof.

21 . A method according to claim 20 , wherein

the step of separating the cornea to form a first corneal layer and a second corneal layer includes allowing a portion of the flap to remain attached at the periphery thereof, said portion of the flap remaining attached to the periphery and the area attached at the main optical axis are configured to be aligned with the astigmatic axis of the eye.