Definition
LASIK is eye surgery that permanently changes the shape of the cornea (the clear covering on the front of the eye) in order to improve vision and reduce a person's dependency on glasses or contact lenses.
See also: Corneal surgery
Alternative Names
Laser-Assisted In Situ Keratomileusis; Laser vision correction
Description
For clear vision, the eye's cornea and lens must bend (refract) light rays properly, so that images are focused on the retina. If the light rays aren't clearly focused on the retina, the images you see are blurry.
This blurriness is referred to as a "refractive error." It is caused by an imperfectly shaped eyeball, cornea, or lens. LASIK uses an Excimer Laser (an ultraviolet laser) to precisely remove corneal tissue to correct the shape for better focusing.
A complete eye examination will be done before surgery to make sure your eyes are healthy. Other tests will be done to measure the curve of the cornea, the size and position of the pupils, the shape of the eyes (to make sure LASIK is an option), and the thickness of the cornea (to make sure you will have enough cornea tissue left after surgery).
A signed informed consent form is needed before the procedure, confirming knowledge of the risks, benefits, alternative options, and possible complications.
LASIK is an outpatient surgical procedure and will take 10 to 15 minutes for each eye.
The only anesthetic used is an eye drop that numbs the surface of the eye. The procedure is done with the person awake. LASIK may be done on one or both eyes during the same session.
During LASIK, a special knife (a microkeratome) is used to cut a hinged flap of corneal tissue off the outer layer of the eyeball. The flap is lifted out of the way and a special laser is used to reshape the underlying corneal tissue.
The calculation for how much tissue is removed by the laser is done ahead of time. Once the reshaping is done, the surgeon replaces and secures the flap. No stitches are needed. An eye shield or patch will be placed over the eye to protect the flap and to help prevent rubbing or pressure on the eye until it has had enough time to heal.
In LASIK surgery, the eye is held...
How is Lasik surgery done?
