How effective is LASIK or laser eye surgery for the correction of nearsightedness? What are the risks?

Charlene

Laser vision correction today is a very effective procedure for reducing myopia (nearsightedness). It is estimated that over 800,000 people will have laser vision correction in the United States during 1999. There are two main procedures: PRK and LASIK. Both use a cool laser beam that reshapes the surface of the eye. Both take approximately 10 minutes per eye and are generally safe procedures, but like any surgical procedure, they both involve risks.

PRK stands for photo refractive keratectomy. This procedure uses an excimer laser to precisely reshape the surface of the cornea (the transparent, dome-shaped lens on the front of the eye). Since people who are nearsighted generally have steep corneas, the laser flattens the cornea, changing the angle of the lens to reduce or eliminate the myopia. Vision slowly improves over three to four days.

LASIK stands for laser-assisted in-situ keratomileusis. This surgery begins by making a flap in the cornea. The thin corneal flap is opened to reveal the "bed" of the cornea. The excimer laser than reshapes the corneal bed, and the flap is brought back into place. The flap seals down tightly without the need for stitches. Although the eye may feel scratchy over the first few hours after LASIK, patients generally do not complain of any further discomfort. Recovery time is faster than with PRK.

These two approaches produce similar results at three months and one year after surgery. Ninety-five percent of patients end up able to drive a car legally without glasses (20/40 vision), and 65-75 percent of patients gain even better improvement, to 20/20 vision.

Laser vision correction does have risks. Many patients will develop a "dry eye" condition that lasts weeks or months. The symptoms of dry eye include a scratchy feeling and mild blurring of vision. Dry eye is easily treated with artificial tears, and it improves over time. A small percentage of patients report a more bothersome condition -- a worsening of vision as well as ghosting or glare symptoms while driving at night. Most of these symptoms will gradually fade over many months, but some patients will have permanent changes in their vision. The most serious complication is fortunately the most uncommon -- infection or severe inflammation of the cornea. Both the infection and inflammation are treatable, but some patients experience permanent loss of vision.