| 摘要 |
PCT No. PCT/US94/11572 Sec. 371 Date Apr. 25, 1997 Sec. 102(e) Date Apr. 25, 1997 PCT Filed Oct. 12, 1994 PCT Pub. No. WO95/17145 PCT Pub. Date Jun. 29, 1995A method and device for benign, non-surgical external shaping of corneal tissue to compensate, by refractive correction, for deviations from normal focussing. Corneal tissue is externally gently removed by erosion to a maximum 30% depth, within several seconds, by an imperceptibly felt, highly controlled and limited area, isotonic water jet, exerting a total force of at most several ounces. The jet is directed to erode corneal tissue to provide an increase in curvature to correct for far-sightedness i.e., to refocus a perceived image from beyond retina onto the surface of the retina. To correct for near-sightedness and to refocus a perceived image from in front of the retina onto the surface of the retina, the jet is directed to flatten out by eroding, a central portion of corneal tissue, to decrease curvature. The jet is either applied by a nozzle or array of nozzles. The jet is applied and directed, in a computer controlled, raster or similar type movement, until the desired diopter change is effected. Since there is no heating of the cornea, with concomitant wound healing induced deviations, correction can be effected within a deviation range from normal of 0.25 diopters, comparable to that of corrective lenses and contact lenses. |
