PRK was FDA approved in 1995, with initial treatments in 1989.

“the treatment in 89 was part of clinical trials missed for sure it was part of the club so let's explain what prk does right before lasik yeah so the way it works is that you uh you have the cornea again like the glass on a watch the thing a contact lens would sit on and let's say that the person is nearsighted the cornea in that person is a little bit too steep to focus the light perfectly on their retina another way of looking at it is that then again the cornea is about two millimeters thick now the coin's got a half a millimeter thick it's about 500 microns maybe a little more um so either the cornea is a little too steep”