Which of the two laser-surgery procedures to correct myopia is considered to be better? Each method has its cheerleaders.

C.L.

The two procedures to which you refer are called photorefractive keratectomy (PRK) and laser in-situ keratomileusis (LASIK). Both procedures take about 10 minutes per eye, and, in both, doctors use a cool laser to reshape the cornea, thereby correcting a patient's vision. The difference between the two operations lies in where the corneal tissue is removed. In PRK, the laser is used to remove tissue from the surface of the cornea. With LASIK, the surgeon makes a flap in the cornea and then lifts the flap up so the laser can remove underlying corneal tissue. After the laser treatment is completed, the flap is repositioned.

PRK and LASIK both provide excellent results with very low risks of complications. With both procedures, about 95 percent of people will end up with vision good enough to legally drive a car without glasses (20/40 vision). The main difference is that the recovery period with PRK lasts three to seven days, while most people who undergo LASIK experience dramatic improvements in vision within 24 hours.

In patients with extreme nearsightedness (high myopia), PRK does pose a greater risk than LASIK for complications that can lead to corneal haze and decreased vision (about 1 percent of such patients). Therefore, many doctors recommend LASIK over PRK for people with high myopia. So, if you are severely nearsighted and are considering laser-vision correction, it's important to discuss your options with a surgeon who is familiar with the pros and cons of both procedures.