Both LASIK and PRK utilize the same excimer laser treatment, therefore, giving the same potential visual outcome. The difference is primarily how the eye is prepped for the laser.
During LASIK, a special device creates a hinged flap of thin corneal tissue, and the flap is gently folded away. The laser reshapes the underlying tissue, and the surgeon replaces the corneal flap over the treated area, where it bonds securely with time. Functional vision returns very rapidly, with the majority of patients seeing well enough to drive the next day without glasses or contact lenses.
PRK, unlike LASIK, does not require a cornea flap to be made. During treatment, the outermost layer of cells, the epithelium, is removed from the surface of the eye. An excimer laser beam then flattens and sculpts the surface to the precise level to produce your personal best vision. It is not to be confused with the older RK surgery which used a knife to make actual cuts around the cornea.
After treatment, a protective contact lens is placed on the eye to make it more comfortable during the healing process. Usually, within five days, the epithelium has fully resurfaced the cornea and the lenses are then removed by your surgeon. You should expect some moderate discomfort for the first 24-48 hours following surgery. You will be given instructions on how to manage the discomfort as well as eye drops to speed healing and prevent infection. The PRK healing time is slightly longer than LASIK. Though you do have “functional” vision after surgery, it is usually somewhat blurred while the epithelium is smoothing out. Your full visual results may not be recognized for four to eight weeks. Patience is key with PRK!
To be a good candidate for LASIK, the cornea must be of sufficient thickness to allow for the flap to be made. PRK may be recommended over LASIK for patients who have thin corneas or who show signs of cornea abnormalities.
To summarize the primary differences between LASIK and PRK are that LASIK offers patients less if any, post-operative discomfort and a quicker return to functional vision although there is an extended corneal flap healing period. On the other hand, PRK is the safest procedure due to the lack of having a corneal flap thus reducing chances of having any complications and having a faster healing time. However, because PRK has a larger surface area to re-grow tissue, there is often more discomfort during the healing process. Although you do have “functional” vision after surgery, it usually takes 4-8 weeks after surgery to achieve your FULL visual outcome.
Even if you see great after surgery, you may still need reading glasses once over the age of 40. This is because the eye’s natural lens stiffens as you age, a condition called presbyopia. Your distance vision should remain crisp, but seeing up close will be more difficult. NOTE: You may need reading glasses after either LASIK or PRK even if you did not wear them before.