Method and device for producing curved cuts in a transparent material
The invention relates to a method for forming curved cuts in a transparent material, in particular in the cornea, by the creation of optical perforations in said material using laser radiation that is focused in the material. The focal point is displaced three-dimensionally to form the cut by lining up the optical perforations. The focal point is displaced in a first spatial direction by a displaceable lens and said focal directions, in such a way that it follows the contours of the cut, which lie on a plane that is substantially perpendicular to the first spatial direction.
1. A method of producing a three dimensional curved cut in an interior of transparent material of an eye, the method comprising:
defining a 3D shape of the curved cut relating to a natural topography of a front face of the eye;
immobilizing the eye by pressing a contact glass onto the front face of the eye, wherein the contact glass deforms the front face of the eye;
determining a change in topography of the front face caused by the contact glass deforming of the front face;
defining 3D focus positions on basis of the 3D shape of the curved cut related to the natural topography of the front face of the eye and the change in topography between the natural topography of the front face of the eye and the topography of the front face of the eye as deformed by the contact glass;
focusing laser radiation to a focus point in the interior of the material;
3D shifting the focus point over the focus positions;
generating optical breakthroughs in the material during the 3D shifting to produce the three dimensional curved cut from a series of optical breakthroughs.
2. The method according to claim 1 , further comprising selecting the transparent material to be a cornea of the eye.
3. The method according to claim 1 , further comprising selecting the 3D shape of the curved cut relating to the natural topography to be spherical ellipsoidal or toroidal.
4. The method according to claim 1 , further comprising making the series of optical breakthroughs follow a spiral, at least in sections of the cut.
5. The method according to claim 4 , further comprising making distances between adjacent path lines of the spiral substantially constant.
6. The method according to claim 4 , further comprising making distances between adjacent path lines of the spiral constant within a tolerance of plus or minus about ten percent.
7. The method according to claim 1 , further comprising selecting the contact glass to comprise a spherical contact surface which is pressed onto the front face of the eye.
8. The method according to claim 1 , further comprising selecting the contact glass to comprise a contact surface of known shape which is pressed onto the front face of the eye and wherein determining the change in topography of the front face caused by the contact glass deforming of the front face comprises taking known shape of the contact surface as shape of the front face deformed by the contact glass.
9. The method according to claim 8 , wherein determining the change in topography of the front face caused by the contact glass deforming of the front face further comprises determining a transformation of coordinates relating to the natural and un-deformed front face of the eye into coordinates relating to the front face deformed by the contact glass.
10. The method according to claim 9 , further comprising selecting the contact surface to be spherical and describing the transformation by φ′=φ, α′·R′=α·R, and R G −R′=R Cv −R, wherein R, φ, α are spherical coordinates relating to the natural and un-deformed front face of the eye, R′, φ′, α′ are spherical coordinates relating to the contact surface, R Cv is a radius of curvature of the cornea, and R G is a radius of curvature of the spherical contact surface.
11. The method according to claim 1 , further comprising:
defining a desired correction of visual deficiencies of the eye, and
determining a volume to be removed from the eye required to obtain the desired correction,
wherein defining the 3D shape of the curved cut comprises defining the cut such that it circumscribe the volume and prepares the volume for extraction from the eye.
12. The method according to claim 11 , further comprising determining the volume to be located fully below the front face of the eye.
13. The method according to claim 12 , further comprising extracting of the volume thereby changing a curvature of the front face of the eye.
14. A method of eye treatment comprising producing a three-dimensional curved cut in an interior of transparent material of an eye, the method comprising:
defining a 3D shape of the curved cut relating to a natural topography of a front face of the eye;
immobilizing the eye by pressing a contact glass onto the front face of the eye, wherein the contact glass deforms the front face of the eye;
determining a change in topography of the front face caused by the contact glass deforming of the front face;
defining 3D focus positions on basis of the 3D shape of the curved cut related to the natural topography of the front face of the eye and the change in topography between the natural topography of the front face of the eye and the topography of the front face of the eye as deformed by the contact glass;
focusing laser radiation to a focus point in the interior of the material;
3D shifting the focus point over the focus positions;
generating optical breakthroughs in the material during the 3D shifting to produce the 3D shaped cut from a series of optical breakthroughs,
wherein the cut circumscribes a volume which is located fully below the front face of the eye so that the volume that is circumscribed is removable from the eye, and
further comprising removing the volume from the eye by pulling the volume from the eye after the cut has been generated.
15. The method according to claim 14 , further comprising selecting the transparent material to be a cornea of the eye.
16. The method according to claim 14 , further comprising selecting the 3D shape of the curved cut relating to the natural topography to be spherical ellipsoidal or toroidal.
17. The method according to claim 14 , further comprising making the series of optical breakthroughs to follow a spiral, at least in sections of the cut.
18. The method according to claim 17 , comprising making distances between adjacent path lines of the spiral to be substantially constant.
19. The method according to claim 17 , further comprising making distances between adjacent path lines of the spiral to be constant within a tolerance of plus or minus about ten percent.
20. The method according to claim 14 , further comprising selecting the contact glass to comprise a spherical contact surface which is pressed onto the front face of the eye.
21. The method according to claim 14 , further comprising selecting the contact glass to comprise a contact surface of known shape which is pressed onto the front face of the eye and wherein the step of determining the change in topography of the front face caused by the contact glass deforming of the front face comprises taking known shape of the contact surface as shape of the front face deformed by the contact glass.
22. The method according to claim 21 , wherein determining the change in topography of the front face caused by the contact glass deforming of the front face further comprises determining a transformation of coordinates relating to the natural and un-deformed front face of the eye into coordinates relating to the front face deformed by the contact glass.
23. The method according to claim 22 , further comprising selecting the contact surface to be spherical and describing the transformation by φ′=φ, α′·R′=α·R, and R G −R′=R Cv −R, wherein R, φ, α are spherical coordinates relating to the natural and un-deformed front face of the eye, R′, φ′, α′ are spherical coordinates relating to the contact surface, R Cv is a radius of curvature of the cornea, and R G is a radius of curvature of the spherical contact surface.
24. The method according to claim 14 , further comprising:
defining a desired correction of visual deficiencies of the eye, and
determining a volume to be removed from the eye required to obtain the desired correction,
wherein the step of defining the 3D shape of the curved cut comprises defining the cut such that it circumscribe the volume and prepares the volume for extraction from the eye.
25. The method according to claim 24 , further comprising describing the volume to be located fully below the front face of the eye.
26. The method according to claim 25 , further comprising extracting the volume thereby changing a curvature of the front face of the eye.