Health A-Z

Medical Content Created by the Faculty of the Harvard Medical School


What Is It?

LASIK is an innovative form of eye surgery. It uses a laser to reshape the cornea. LASIK stands for "laser in situ keratomileusis."

The cornea is the clear, round "window" of tissue that allows light to enter the front of the eye. By reshaping the cornea, the surgeon adjusts the focus of light on the retina. (The retina is the layer at the back of the eye responsible for sight.)

LASIK surgery often improves vision in people who have nearsightedness, farsightedness or certain other vision problems.

In LASIK, the eye surgeon first cuts a small, hinged flap of tissue from the front of the cornea. This is done with an instrument called a microkeratome. Once this flap is moved out of the way, a laser is used to reshape the underlying protein fibers (collagen) of the cornea.

This reshaping is based on precise measurements made by the eye doctor during the presurgery exam. When the laser reshaping is done, the corneal flap is moved back into place.

The cornea heals quickly. As a result, many people who have LASIK surgery notice dramatic improvements in vision almost immediately.

LASIK is an outpatient procedure. This means there is no overnight stay in a hospital. It generally takes 10 to 15 minutes for each eye.

Some surgeons work on both the right and left eyes at one sitting. Other surgeons do LASIK on only one eye first. Then, after achieving a good result with the first eye, they do LASIK on the second eye.

LASIK is the most common surgical treatment to correct nearsightedness in the United States. The technique has been used successfully in the U.S. since 1991. However, because the procedure is still relatively new, the long-term effects of LASIK remain unknown. People should have a clear understanding of the potential risks and complications of LASIK surgery.

In addition, most health insurance policies do not cover LASIK surgery. People must pay the entire cost of the procedure themselves. The cost varies, but it usually amounts to several thousand dollars per eye.

Page 1 of 9     Next Page:  LASIK What It's Used For
Click here to to redeem your SparkPoints
  You will earn 5 SparkPoints
From Health A-Z, Harvard Health Publications. Copyright 2007 by the President and Fellows of Harvard College. All rights reserved. Written permission is required to reproduce, in any manner, in whole or in part, the material contained herein. To make a reprint request, contact Harvard Health Publications. Used with permission of StayWell.

You can find more great health information on the Harvard Health Publications website.