n. an operation in which a part of the cornea is removed, usually a superficial layer. This procedure is now frequently done by an *excimer laser, either to correct refractive errors (myopia, hypermetropia), by reshaping the surface of the cornea (photorefractive keratectomy; PRK), or to remove diseased corneal tissue (phototherapeutic keratectomy). See also automated lamellar keratectomy.
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