PRK (Photorefractive Keratectomy)
DURING THE PRK PROCEDURE
PRK or Photorefractive Keratectomy was actually the first Excimer laser procedure approved for the correction of nearsightedness in the mid 1990’s. It is presently used for the correction of nearsightedness (myopia), farsightedness (hyperopia), and astigmatism. Like LASIK, PRK uses the laser to gently reshape the surface of the eye providing clearer vision. Unlike LASIK, PRK does not involve the creation of a surface flap.
With LASIK, a Femtosecond Laser is first used to create a thin flap in the cornea (the front windshield of the eye). This flap is then retracted out of the operative field and laser is applied to the underlying corneal tissue. The flap is subsequently replaced into its original position. PRK, however, has no flap. The Excimer Laser reshaping treatment is instead applied directly onto the surface of the eye to perform the visual corrections. Since there is no flap to replace over the treated surface, a contact lens is placed on the eye to promote healing and to provide comfort. This lens requires no maintenance and is usually removed after several days by your doctor. PRK typically provides excellent results for patients with low to moderate myopia, astigmatism and hyperopia.
PRK vs. LASIK
PRK has advantages over LASIK. For example, while rare, the possibility of a flap complication with LASIK procedures does exist. However, since there is no flap with PRK, there is no risk of this problem. PRK is also an option for many patients who cannot have LASIK due to significant dry eye problems or if the cornea is too thin for LASIK.
The surface usually takes 3-6 days to heal sufficiently for the contact lens to be removed. Visual recovery then takes an additional period of time from days to weeks. This is in contrast to LASIK where visual recovery is measured in hours or a few days. One other disadvantage of PRK is the need to use eyedrops for a longer period of time, sometimes several months versus a few days for LASIK. However the visual results with PRK are excellent and provide a viable alternative to LASIK for some patients.