Before the development of LASIK, PRK (photorefractive keratectomy) used to be the most common refractive surgery procedure. PRK was invented in the early 1980s although the first FDA approval of a laser for PRK was in 1995.
PRK is performed with an excimer laser, which uses a cool ultraviolet light beam to precisely remove small amounts of tissue from the surface of the cornea. The goal of the laser procedure is to reshape the cornea in order to correct the focusing ability of the eye.
PRK takes just a few minutes and is done under topical anesthesia.
This type of laser vision correction does not require any corneal incision at all. Only the most superficial layer of the cornea is gently removed either with a laser or with a tiny surgical brush. The excimer laser is then used to reshape the deeper layers of the cornea, allowing for correction of nearsightedness, farsightedness and astigmatism. After the laser has completed the reshaping procedure, a protective contact lens is then placed over the treated area to allow for faster healing and less discomfort.
During PRK, less tissue is removed than with traditional Lasik. Patients with thin corneas, dry eyes, large pupils, or those who have had previous vision correction such as RK, may now have laser vision correction safely performed.
PRK is used to safely and permanently correct nearsightedness, farsightedness and astigmatism.
People who are nearsighted have difficulty seeing things at a distance because their corneas are too steep. To treat nearsightedness, the cornea is made flatter by removing tissue from the center of the cornea.
Patients who are farsighted have difficulty seeing things up close and also sometimes at a distance, because their corneas are too flat. To treat farsightedness, the flat cornea is made steeper by removing peripheral tissue in a ring shape on the outer edges of the cornea. This steepens the central visual part of the cornea.
Astigmatism means that the eye has an oval or football shape. Patients with astigmatism have blurred vision both at a distance and up close. The laser reduces the oval shape making the focusing ability clear in all directions. The laser is used to treat astigmatism at the same time as nearsightedness and farsightedness.
Patients generally have had marvelous results with PRK eye surgery. The main benefit of PRK surgery is the removal of less tissue than in traditional LASIK making it an option for patients with very high prescriptions and/or thin corneas.