PRK (photorefractive keratectomy): A kind of laser eye surgery designed to change the shape of the cornea to eliminate (or reduce) the need for glasses and contact lenses. The laser is used to remove the outer layer of the cornea and flatten the cornea. The flattening of the cornea is intended to correct myopia (nearsightedness) and astigmatism (uneven curvature of the cornea that distorts vision). PRK is an ambulatory procedure done in the office with numbing eye drops. It takes about a minute to do and about 3 days to heal. No eye patch need be worn after PRK.