Ablation apparatus for ablating a cornea by laser beam
DCFirst Claim
1. An ablation apparatus for ablating a surface of a cornea to form a transition zone for myopia correction by laser beam, comprising:
- a laser source for emitting a laser beam;
an ablation optical system for ablating the surface of the cornea by the laser beam emitted from said laser source;
ablation area changing means for changing an ablation area on the cornea;
cornea shape forming means for forming a shape of an optical zone of the cornea, the radius of curvature of the shape of the optical zone being larger than the radius of curvature of a pre-operation cornea, by superposing the laser beam through said ablation optical system;
input means for inputting data related to the transition zone, the transition zone to have a shape for smoothly connecting said optical zone with a non-ablation area; and
control means for determining the shape of said transition zone, based on the data and based on a curvature of a pre-operation cornea and a desired post operation cornea, and for controlling movement of said ablation area changing means to achieve the shape of the transition zone.
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Abstract
An ablation apparatus for ablating the surface of a cornea by laser beam having a laser source for emitting a laser beam, an ablation optical system for ablating the surface of a cornea by the laser beam emitted from the laser source, an diaphragm with a variable diameter for changing an ablation area on the cornea, a cornea shape forming device for forming a desired shape of cornea'"'"'s optical zone by superposing the irradiation through the ablation optical system, an input device for inputting a data to determine a transition zone as to be connected the optical zone with a non-ablation area smoothly, and a control device for controlling the diameter of the diaphragm by determining the shape of the transition zone based on the data inputted through the input device.
72 Citations
11 Claims
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1. An ablation apparatus for ablating a surface of a cornea to form a transition zone for myopia correction by laser beam, comprising:
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a laser source for emitting a laser beam; an ablation optical system for ablating the surface of the cornea by the laser beam emitted from said laser source; ablation area changing means for changing an ablation area on the cornea; cornea shape forming means for forming a shape of an optical zone of the cornea, the radius of curvature of the shape of the optical zone being larger than the radius of curvature of a pre-operation cornea, by superposing the laser beam through said ablation optical system; input means for inputting data related to the transition zone, the transition zone to have a shape for smoothly connecting said optical zone with a non-ablation area; and control means for determining the shape of said transition zone, based on the data and based on a curvature of a pre-operation cornea and a desired post operation cornea, and for controlling movement of said ablation area changing means to achieve the shape of the transition zone. - View Dependent Claims (2, 3, 4, 5)
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6. An ablation apparatus for ablating a surface of a cornea by a laser beam comprising:
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a laser source for emitting a laser beam; an ablation optical system for irradiating said laser beam emitted from said laser source onto the surface of the cornea; ablation area confining means for confining an ablation area on the cornea, said confining means being disposed in said ablation optical system; ablation area changing means for changing said ablation area on the cornea confined by said ablation area confining means; means for determining a sectional form of a transition zone based on a curvature of a pre-operation cornea and a desired curvature of a post-operation cornea, the transition zone being formed between said ablation area and a non-ablation area; and ablation area control means for controlling said ablation area on the cornea to obtain a shape of the transition zone and ensure smooth connection of the transition zone with an optical zone and the non-ablation area. - View Dependent Claims (7, 8, 9, 10)
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11. An ablation apparatus for ablating a surface of a cornea by laser beam comprising:
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a laser source for emitting a laser beam; an ablation optical system for ablating the surface of the cornea by the laser beam emitted from said laser source; ablation area changing means for changing an ablation area on the cornea; cornea shape forming means for forming a shape of an optical zone of the cornea, the radius of curvature of the shape of the optical zone being larger than the pre-operation cornea, by superposing the laser beam through said ablation optical system; input means for inputting data related to a transition zone, the transition zone to have a shape for smoothly connecting said optical zone with a non-ablation area; and control means for determining the shape of said transition zone, based on the data and based on a curvature of a pre-operation cornea and a desired post operation cornea, and for controlling movement of said ablation area changing means to achieve the shape of the transition zone, wherein the transition zone has a sectional form comprising two circles having a radius, RT, such that;
space="preserve" listing-type="equation">R.sub.T =(s.sub.T -S)R.sub.1 R.sub.2 /(S.sub.T R.sub.2 -SR.sub.1),where R1 is the radius of the pre-ablation zone, R2 is the radius of a post-ablation zone, S is the width of the optical zone, and ST is the width of the transition zone.
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Specification