Photorefractive keratotomy (PRK), also spelled keratectomy, is a surgical procedure used to correct common vision problems, including nearsightedness, farsightedness, and astigmatism. During PRK eye surgery, an optometrist uses a low-intensity laser beam to carefully ablate tiny pieces of tissue from the cornea, the clear membrane surrounding the eye. The cornea is reshaped to improve its ability to focus light into the retina. PRK eye surgery is not performed as often as it was in the past because newer technologies and procedures provide shorter healing times and a higher success rate. PRK is still used, however, when patients are not good candidates for other types of surgical procedures for various reasons.
Specialists have been performing PRK eye surgery since the early 1990s. The procedure helps a vast majority of patients achieve near perfect eyesight without the aid of glasses or contact lenses. Before PRK eye surgery, a patient is usually given a sedative and eye drops containing a local anesthetic. The surgeon uses a machine that emits ultraviolet light pulses to delicately burn away parts of the cornea in order to make it round, smooth, and angled appropriately.
Farsighted patients generally have corneas that are too flat, so PRK is used to make them steeper. The opposite is true for nearsighted patients. Astigmatisms that warp the shape of the cornea can also be corrected. In most cases, the procedure can be performed in less than one hour and the patient can leave the surgical center the day of the operation. Light sensitivity, eye pain, and headaches are common for several days following PRK surgery.
By taking prescription medications and following the doctor's orders about proper eye care, a patient can expect to start feeling better in about one week. Vision may be blurry for several more weeks as the corneas continue to heal. In most cases, side effects completely wear off within two months and vision becomes sharp.
Years of research and clinical trials have produced what many optometrists consider a more efficient form of laser eye surgery known as laser-assisted in situ keratomileusis (LASIK). LASIK differs from PRK eye surgery in that the surgeon creates a small opening in the cornea, and removes tissue underneath instead of on the surface. In general, LASIK procedures are quicker to perform, cause less discomfort, and provide a much shorter recovery time. Many patients have normal vision after two or three days, compared to two or three months with PRK eye surgery.
During an initial consultation with an optometrist, he or she can determine if the patient is a better candidate for LASIK or PRK. People who have especially thin corneas generally benefit more from PRK, as cutting into the cornea could result in accidental damage to the underlying tissue. In addition, PRK is often preferred when astigmatism severely misshapes the cornea. A doctor can explain the risks and benefits of each procedure in detail during a consultation.