photorefractive keratectomy (PRK) /-refrak″tiv/ , a surgical procedure in which an excimer laser is used to reshape the human cornea to improve the refractive properties of the eye and reduce or eliminate the need for eyeglasses. The excimer laser does not require that incisions be made in the cornea. Rather than cutting, the laser shaves off preprogrammed outer layers of corneal tissue. The excimer laser is programmed to emit a measured and concentrated light beam to reshape a small part of the central cornea. It allows for correction of myopia of up to −10.0 diopters. Compare radial keratotomy. See also refractive keratotomy.
