eye disorders
Surgery for Refractive Errors
Photorefractive Keratectomy (PRK)
PRK is used primarily to correct nearsightedness, astigmatism, and farsightedness. PRK requires use of an excimer laser to reshape the cornea. Unlike LASIK, no flap is created. The cells on the surface of the cornea are removed at the start of the procedure. As in LASIK, computer-controlled pulses of highly focused ultraviolet light remove small amounts of the cornea and thus change its shape to better focus light onto the retina and improve vision without eyeglasses or contact lenses. A contact lens is placed on the eye after the surgery and acts as a bandage (called a bandage contact lens). It helps the surface cells grow back and helps relieve pain. This procedure usually takes 5 minutes per eye. Complications include possible haze formation (causing blurred or cloudy vision) if a large amount of corneal tissue is removed. Also, people need to use corticosteroid eye drops for several months after surgery. Use of corticosteroid eye drops may cause Glaucoma . Therefore, doctors closely monitor people who are using corticosteroid eye drops. Severe, vision-threatening infection of the cornea is also a rare complication. Although there is more discomfort and longer healing time with PRK than with LASIK (because the removed surface cells need to grow back), PRK can sometimes be done on people who cannot have LASIK, such as those with a loose corneal surface layer or slightly thin corneas. 