PRK (photo-refractive keratectomy) is a laser vision correction procedure which predates LASIK. It corrects the vision by reshaping the cornea in essentially the same way that LASIK does but without first creating a flap of tissue. In PRK, on the other hand, the Excimer laser correction is applied directly to the surface after gently debriding the outer layer known the epithelium. Since there is no protective flap, a bandage contact lens is placed on the cornea until it is healed, usually within four to seven days. For this reason, it takes a bit longer for the vision to clear and for the irritation to resolve. PRK is used when patients are not candidates for LASIK and include patients who have dry eyes, thin corneas, irregularity of the surface layers, or occupational reasons (martial artists, corrections officers, certain law enforcement or military). Your surgeon will determine if you are a candidate for LASIK or PRK and advise you accordingly.