LASIK eye surgery can be an alternative to glasses or contact lenses done for the correction of certain common vision problems.

LASIK (laser-assisted in situ keratomileusis) is a type of laser refractive surgery — the best known and most commonly performed. In general, a special type of cutting laser is used to precisely change the shape of your cornea — the dome-shaped transparent tissue at the front of your eye — to improve vision.

WHY IS IT DONE?

LASIK surgery may be an option for the correction of one of these vision problems: Nearsightedness (myopia). When your eyeball is slightly longer than normal or when the cornea curves too sharply, light rays focus in front of the retina and blur distant vision. You can see objects that are close fairly clearly, but not those that are far away. Farsightedness (hyperopia). When you have a shorter than average eyeball or a cornea that is too flat, light focuses behind the retina instead of on it. This makes near vision, and sometimes distant vision, blurry. Astigmatism. When the cornea curves or flattens unevenly, the result is astigmatism, which disrupts focus of near and distant vision.

LASIK is usually not advisable if you:

Have an eye disease called keratoconus, or if you have a family history of it

Have fairly good overall vision

Have severe nearsightedness

Have very large pupils or thin corneas

Have age-related eye changes that cause you to have less-clear vision (presbyopia)

Participate in contact sports that may be associated with blows to the face

Results

LASIK often offers improved vision without the hassle of glasses or contact lenses. In general, you have a very good chance of achieving 20/25 vision or better after refractive surgery.

More than 8 out of 10 people who've undergone LASIK refractive surgery no longer need to use their glasses or contact lenses for most of their activities.

Your results depend on your specific refractive error and other factors. People with a low grade of nearsightedness tend to have the most success with refractive surgery. People with a high degree of nearsightedness or farsightedness along with astigmatism have less predictable results. In some cases, the surgery might result in undercorrection. If this happens, you might need another surgery to achieve the proper correction.

Rarely, some people's eyes slowly return to the level of vision they had before surgery.This might happen due to certain conditions, such as abnormal wound healing, hormonal imbalances or pregnancy. Sometimes this change in vision is due to another eye problem, such as a cataract. Talk with your doctor about any vision changes.