Device and process for machining the human eye using laser technology
A device for machining the human cornea with focused laser radiation includes controllable components for setting the location of the radiation focus, a control computer for controlling these components, and also a control program for the control computer. The control program contains instructions that have been designed to bring about, upon execution by the control computer, the generation of incisions in the cornea in accordance with a predetermined incision figure, the incision figure defining a corneal bed, a flap situated on the bed and also at least one tissue strip situated in the region of the peripheral edge of the flap between the bed and the flap and extending along the edge of the flap. After the flap has been folded away, the tissue strip has to be removed and enables a creaseless post-ablative close fitting of the folded-back flap against the surface of the bed. In this manner, microstriae which may impair the visual capacity can be avoided.
1. A device for machining the human cornea with focused laser radiation, comprising:
controllable components for setting the location of the radiation focus;
a control computer for controlling these components; and
a control program for the control computer, the control program containing instructions configured to bring about, upon execution by the control computer, the generation of incisions in the cornea in accordance with a predetermined incision figure, the incision figure defining a corneal bed, a flap situated on the bed, and at least one tissue strip situated in the region of a peripheral edge of the flap between the bed and the flap and extending along the edge of the flap, the tissue strip being fully separable from the flap by the focused laser radiation, the tissue strip having a radial width perpendicular to and intersecting with the peripheral direction of the edge of the flap, the radial width also being parallel to the radial direction of the anterior surface of the cornea, the radial width increasing from the most anterior point of the strip towards the deepest surface of the strip.
2. A device according to claim 1 , wherein the tissue strip extends substantially over the entire peripheral length of the edge of the flap.
3. A device according to claim 1 , wherein the tissue strip extends only over a part of the peripheral length of the edge of the flap.
4. A device according to claim 3 , wherein the incision figure defines a plurality of at least two tissue strips which extend along different peripheral regions of the edge of the flap.
5. A device according to claim 1 , wherein the tissue strip is situated completely beneath the anterior surface of the cornea.
6. A device according to claim 1 , wherein the radial width varies in the peripheral direction of the edge of the flap.
7. A device according to claim 1 , wherein the tissue strip has a cross-section that is perpendicular to the peripheral direction of the edge of the flap, the cross-section being wedge-shaped.
8. A device according to claim 1 , wherein the incisions include a first incision, defining the underside of the flap, situated totally deep within the cornea and preferentially extending parallel to the anterior surface of the cornea, and also two second incisions, spaced from one another, preferably running into the first incision in angled manner and delimiting the tissue strip between themselves and the first incision, of which at least one is conducted out to the anterior surface of the cornea.
9. A device according to claim 8 , wherein the two second incisions run into one another beneath the anterior surface of the cornea.
10. A device according to claim 1 , wherein the control computer is configured to access ablation data representative of a corneal ablation profile, the control computer being adapted to determine, on the basis of the ablation data, the incision figure in a manner depending on the peripheral location of the edge of the flap.