What is photorefractive keratectomy?
Photorefractive keratectomy (PRK) is a corneal modification procedure to reduce and/or correct nearsightedness (myopia). An excimer laser is used to make the modifications. It produces a uniform, concentrated beam of high energy ultraviolet light that can be precisely focused onto the cornea (the clear outside surface of the eye). This flattens the surface of the cornea and changes its focusing power. The procedure reduces nearsightedness by moving the focus of the image closer to the retina.
What is nearsightedness?
In an eye with 20/20 vision, the cornea helps to focus light rays on the retina (the back inside surface of the eye). In the nearsighted eye, light rays are focused in front of the retina, resulting in blurred distance vision.
How is PRK performed?
PRK is done as an outpatient procedure and generally only one eye is done at a time. Before PRK, patients get anesthetic eye drops. During the procedure, the excimer laser’s ultraviolet light energy is focused on the cornea. It is converted into chemical energy which evaporates molecules of corneal tissue in very precise amounts. Following the procedure, the doctor puts antibiotics in the patient’s eye and an eye patch or bandage contact lens is applied. The first follow-up visit is scheduled for the day after the procedure. Continued follow-up is required for three to four months.
Who is a candidate for PRK?
Photorefractive keratectomy may be considered to decrease dependence on spectacles or contact lenses for cosmetic, occupational or recreational reasons. Patients who are interested in PRK should first have a comprehensive eye examination by their optometrist to evaluate their eye health and determine their vision needs.
Candidates for PRK should be age 21 or older with stable vision and no abnormalities of the cornea or external eye. PRK is currently approved for people with low to moderate nearsightedness with low amounts of astigmatism.
Patients should understand the benefits, risks and complications of the procedure before undergoing PRK.
How effective and safe is PRK?
U.S. Food and Drug Administration clinical studies have shown PRK to be generally safe and effective, but the long-term effects of the procedure on eye health and vision are unknown and continue to the studied. Effects of the procedure include discomfort, glare sensitivity especially at night, distorted or fluctuating vision and undercorrection or overcorrection of nearsightedness.
PRK does not eliminate the need for lens correction for presbyopia, the loss of near focusing ability that occurs as people age (usually after age 40).
Where can patients get more information about PRK?
Patients who are considering PRK should consult Dr. Reeves. She can advise them about PRK and other available treatments and can provide appropriate patient care and treatment.