What is PRK?
PRK (photorefractive keratectomy) is a type of refractive surgery to correct myopia (nearsightedness), hyperopia (farsightedness) and astigmatism.
PRK was the first type of laser eye surgery for vision correction and is the predecessor to the popular LASIK procedure. Though PRK recovery takes a bit longer than recovery from LASIK eye surgery, PRK is still commonly performed and offers advantages over LASIK for some patients.
Like LASIK and other types of laser eye surgery, PRK works by reshaping the cornea using an excimer laser, allowing light entering the eye to be properly focused onto the retina for clear vision.
The main difference between PRK and LASIK is that in LASIK surgery a thin, hinged flap is created on the cornea to access the treatment area, whereas in PRK the cornea’s entire epithelial (outer) layer is removed to expose the area and no flap is created. For both PRK and LASIK, the excimer laser then sculpts the stromal layer of the cornea to correct your refractive error.
A variation of PRK, called LASEK, also is available. Instead of removing the outer epithelial layer of the cornea as with PRK, LASEK involves lifting the epithelial layer, preserving it during surgery and then replacing it on the eye’s surface at the end of the procedure.
LASEK has decreased in popularity due to the slower recovery of vision compared with PRK, as the replaced epithelial layer takes longer to recover in LASEK than the growth of a new epithelial layer in PRK.
The final results of PRK surgery are comparable to LASIK outcomes, but initial PRK recovery is slower because it takes a few days for new epithelial cells to regenerate and cover the surface of the eye.
There also is a slightly increased risk of eye infection and haziness of vision in the first few days after surgery. LASIK patients generally have less discomfort, and their vision stabilizes more quickly, whereas vision improvement with PRK is gradual and the final outcome can take several weeks.
This is of particular benefit if the cornea is too thin for LASIK or if you have undergone LASIK previously and therefore have a thinner residual cornea. There also is no risk of flap complications, and the risk of removing too much of the cornea with the excimer laser is reduced.
PRK laser eye surgery has been performed overseas since the 1980s and in the United States since 1995 and has a very high success rate. It has undergone significant advancements during this time and remains the treatment of choice in certain circumstances.
PRK and LASIK results are similar. Most people achieve 20/20 vision after PRK surgery, and nearly all patients achieve 20/40 visual acuity or better. Some patients may still need to wear eyeglasses or contact lenses, but the prescription will be significantly lower than before the procedure.