Computer control for bio-mechanical alteration of the cornea

摘要

A system and method for altering the shape of a lamina of transparent material (e.g. the cornea of an eye), as it is being subjected to a transverse pressure differential, requires a computer controlled laser unit. In accordance with specified input parameters, the computer directs the laser unit to perform LIOB over predetermined surfaces within the lamina. This weakens the material for a desired reshaping of the lamina in response to the pressure differential. With respect to a perpendicular axis that is defined by the lamina, surfaces parallel to the axis (e.g. cylindrical surfaces) are separated from each other by about two hundred microns. For surfaces perpendicular to the axis, the separation is about ten microns. In each instance, the cuts that result from LIOB are only about two microns thick.

主权项

1. A method for controlling a laser beam to perform an intrastromal ophthalmic surgical procedure to alter the shape of a transparent lamina in an eye, the method comprising the steps of:
electronically connecting a computer with a laser unit; identifying an axis substantially perpendicular to the lamina, wherein the axis establishes a reference datum for movement of the laser beam; creating a predetermined computer program for directing the laser unit to make a first surface enclosed within the lamina in accordance with requirements of the surgical procedure and a second surface unconnected with the first surface, wherein the surfaces are substantially parallel, and are defined relative to the axis to weaken the lamina; determining cutting parameter coordinates for each of the surfaces; entering the cutting parameter coordinates into the computer, wherein the cutting parameter coordinates are defined relative to the axis; generating a laser beam with the laser unit; focusing the laser beam to a focal spot in the lamina; and moving the focal spot in accordance with the cutting parameters, to perform Laser Induced Optical Breakdown (LIOB) over each defined surface inside the lamina, and wherein said first surface and said second surface each have a thickness of approximately two microns to weaken the lamina and alter the shape of the lamina in response to forces imposed on the eye parallel to the axis.