Photorefractive keratectomy (PRK), is a refractive procedure in which a laser is used to help correct the vision. An excimer laser is used on the cornea to help correct the refractive error or decrease the dependency on glasses or contacts. The PRK rescuplts the shape of the cornea so that the light can reach the retina. During PRK the epithelium, the top layer of the cornea, is removed. With the epithelium removed, a laser can be directed at the underlying corneal tissue which then can be remodified to correct nearsightedness, farsightedness, and/or astigmatism. Once the cornea has been changed a contact is placed over the eye so healing can take place. It normally takes up to a week for the cornea to heal.