Acronym for laser in-situ keratomileusis, which is a variety of surgery of the EYE used to correct severe myopia (short-sightedness – see REFRACTION; EYE, DISORDERS OF). A thin flap of the cornea is lifted, the area underneath reshaped using an EXCIMER LASER, and the flap is then returned to its place, the altered contour of the cornea improving the patient's sight.