Although you may not be a candidate for LASIK, the most popular refractive procedure performed today, you may be a candidate for a procedure known as photorefractive keratectomy, or PRK. This procedure delivers the same visual outcomes as LASIK and has dramatically improved the vision of millions of patients unable to undergo the LASIK procedure.
What is PRK?
Like LASIK, PRK is a refractive surgical procedure which uses a laser to reshape the cornea. However, rather than creating a flap and then reshaping the deeper corneal layers, PRK uses the same excimer laser to sculpt directly on the surface layers of the cornea. You can think of PRK as LASIK without the flap. For mild to moderate myopia, only 5 to 10 percent of the thickness of the cornea is removed; for extreme myopia, about 30% of cornea thickness is removed. If you were to measure this tissue, its thickness would be that of 1-3 human hairs. The major benefit to PRK is that the structure of the corneal dome is retained.
The PRK procedure also goes by several other names: LASEK (pronounced LAS-ECK), epi-LASIK, and surface ablation.
History of PRK
PRK was introduced in 1987 and was approved by the U.S. FDA in 1995. Instead of a microkeratome being used to create a corneal flap, with PRK Dr. Kornmehl uses the laser to accurately sculpt the cornea one microscope layer at a time. As awareness of LASIK grew, PRK became less popular, because of the increased discomfort and more rapid recovery of vision that LASIK offered.
In the last decade, a newer generation of excimer lasers, along with refined techniques, have minimized the risks of PRK. And patients today have an easier recovery. As a result, PRK has become a viable option for a variety of patients whose needs are not met by LASIK.
Who Is a Candidate for PRK?
Most people who are candidate for LASIK are also candidates for PRK. The PRK procedure is an especially good fit for people with mild to moderate nearsightedness, farsightedness, and/or astigmatism. Individuals with thin corneas may be better candidates for PRK than for LASIK. As with any laser surgery, your corneas should be healthy and your vision should be stable for at least 1 year prior to the procedure. Also, except in certain situations, you need to be at least 18 years of age to undergo this procedure.