Photorefractive Keratectomy (PRK)
If a person is not a candidate for LASIK surgery—due to factors such as having chronically dry eyes or thin corneas—Photorefractive Keratectomy (PRK) is another option. In the PRK procedure, the eye surgeon removes the epithelium, which is the outermost layer of the cornea. A cool laser beam is applied to the cornea, and a soft contact lens is applied to act as a bandage during the healing process. This lens will be taken out within five to seven days of the procedure.
The recovery period typically lasts one to two weeks, and patients may experience blurry vision and mild to marked discomfort during this time. Most of the improvement in vision is noticed throughout the first month after surgery, but gradual improvement continues over the course of a year following the procedure. PRK patients may also have wavefront-guided or custom laser correction, sometimes called "advanced surface ablation."
What is the Expected Outcome of PRK surgery?
Clinical trials have indicated that PRK is a safe and highly effective treatment for mild to high myopia, hyperopia, and astigmatism. FDA studies using a 6.00 mm zone of photoablation have shown that of 341 eyes studied at six months following surgery, 95 percent were corrected to 20/40 or better without glasses or contact lenses, and 66 percent to 20/20 or better without glasses or contact lenses.
Who is a Good Candidate for Excimer PRK Surgery?
Under current FDA guidelines, candidates for this type of refractive surgery should be 21 years of age or older with a stable refraction of myopia, hyperopia, or astigmatism. PRK should not be performed on people with a history of autoimmune disease (such as lupus erythematosis) because it has been shown that these patients may heal poorly following treatment and have an uncontrolled reaction to the surgery. This procedure is not recommended for pregnant women who often have unstable myopia, nor should it be offered to individuals with a history of corneal dystrophy (inherited degenerations of the cornea), or past viral infection by herpes simplex or herpes zoster (shingles).