Young Ghee Lee, MD PhD

Photorefractive keratectomy (PRK) and LASIK are the two primary procedures for correcting refractive errors using the excimer laser. In PRK, the epithelium is re moved, the exposed stroma is photoablated, and the epithelial defect heals in 2 to 4 days. The LASIK procedure re quires that a hinged flap (consisting of the surface epithelium, Bowman’s membrane and anterior stroma) be created using a microkeratome. The flap is folded back, the exposed stroma is photoablated using an excimer laser, and the flap is then replaced, covering the treated area. After either procedure, flattening of the central corneal curvature from tissue removal results in a decrease in refractive power in myopic correction.