LASIK (Laser In-Situ Keratomileusis) for Nearsightedness

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LASIK (Laser In-Situ Keratomileusis) for Nearsightedness

Surgery Overview

LASIK (laser in-situ keratomileusis) is the most common laser surgery for correcting nearsightedness (myopia) and astigmatism. LASIK makes a small flap in the cornea and removes some of the tissue exposed by the flap. The laser removes tissue from the cornea very accurately without damaging nearby tissues.

What To Expect After Surgery

LASIK is an outpatient procedure. It is done under local anesthesia in a surgeon's office or a same-day surgery center. The operation on one eye takes about 10 to 15 minutes. The entire process usually takes less than 2 hours, including preparation time, care right after the surgery, and paperwork.

After surgery, you may wear a patch or contact lens on the eye and get a prescription for pain medicine. Someone must drive you home and then back to the surgeon's office the next day. During this second visit, the surgeon will examine your eye and prescribe eyedrops to prevent infection and reduce inflammation. More follow-up visits are required, usually the next week and then throughout the first year after surgery.

  • You will feel irritation and scratchiness in the eye on the day of surgery. Your eyes may water a lot.
  • Recovery is usually quick, with only mild discomfort. You may return to your normal activities within a few days.
  • Dry-eye symptoms are common but usually temporary.
  • You may need to wear an eye shield for a few days after surgery.
  • Your vision may be hazy or blurry for a few days or a week after surgery. Do not drive until your vision has cleared.
  • Your doctor may prescribe eyedrops to reduce inflammation and the risk of infection. You may need to use them for several months after surgery.
  • For 2 weeks after surgery, avoid vigorous sports, eye makeup, and activities that may get water in the eye. The surgeon may recommend that you shower before the surgery and then avoid showering for a day or two afterward to keep from getting water in the eye.

LASIK usually requires very little recovery time. Most people who have the surgery see quite well the next day. There is little or no pain after LASIK, unlike photorefractive keratectomy (PRK).

Why It Is Done

LASIK surgery may be used to correct mild to moderate nearsightedness. It is also thought to be the best procedure for correcting high nearsightedness (greater than 7 diopters), although the results of surgery become harder to predict with higher amounts of nearsightedness.

In general, for correcting nearsightedness over 3 diopters, both LASIK and PRK are better than radial keratotomy (RK).

LASIK is an elective, cosmetic procedure that is done to correct nearsightedness in otherwise healthy eyes.

The procedure may not be done for people who:

  • Have not had stable vision for at least 1 year.
  • Are younger than age 18.
  • Are pregnant or breast-feeding.
  • Have a disease or abnormality of the cornea, such as keratoconus or corneal edema.
  • Have an uncontrolled autoimmune or connective tissue disease.

How Well It Works

Over the short term, LASIK has been shown to be very effective in reducing mild to moderate nearsightedness (myopia). Almost everyone notices improvements in their vision. But not everyone gets perfect 20/20 vision.

For people with myopia of less than 6 diopters, studies showed that after surgery, about:1

  • 67 to 72 out of 100 had 20/20 vision or better.
  • 95 to 96 out of 100 had 20/40 vision or better.

For people with myopia between 6 and 12 diopters, studies showed that after surgery, about:1

  • 48 to 64 out of 100 had 20/20 vision or better.
  • 89 to 94 out of 100 had 20/40 vision or better.

Little is known about the long-term outcomes of LASIK. Doctors continue to improve the technique and to study the long-term results.


The risk of complications from LASIK surgery is low and decreases with a more experienced surgeon. Look for a corneal specialist or surgeon who does the surgery often.

Complications and side effects from LASIK may include:

  • Clouded vision (clouding of the cornea as a result of healing). This clouding can be caused by an inflammation under the flap of cornea tissue. The inflammation usually goes away with medicine. But your doctor may need to do a procedure to relieve the inflammation.
  • Night vision problems, such as halos (often described as a shimmering circle around light sources such as headlights or street lamps).
  • Glare, or increased sensitivity to bright light.
  • Double vision (diplopia), usually in one eye.
  • New astigmatism caused by wrinkling in the corneal flap or other flap complications.
  • Loss of best corrected vision, which is the best possible vision you can achieve using glasses or contact lenses.
  • Overcorrection or undercorrection.
  • Dry-eye symptoms starting or getting worse.

Serious vision-threatening complications are rare but may include:

  • Infection of the cornea (keratitis).
  • Elevated pressure inside the eye (intraocular pressure) leading to glaucoma.

LASIK is considered safe. LASIK has been approved by the U.S. Food and Drug Administration (FDA) since 1995. No deaths have been reported as a result of the operation. And serious complications are rare. But the procedure may have long-term side effects or complications that experts do not yet know about.

What To Think About

If you are thinking about having surgery to improve nearsightedness, consider all the options (including LASIK, PRK, epi-LASIK, corneal ring implants, intraocular lens implants, and radial keratotomy), and discuss them with your doctor. Ask your doctor the questions that you have about surgery (for example, what are the risks, benefits, and possible outcomes), so that you understand your options and can make the best decision.

LASIK is being done more frequently than PRK, largely because of the good results and the quicker visual recovery that LASIK offers. There is no agreement about whether LASIK is superior to PRK or vice versa for people with mild to moderate nearsightedness.

It is important to keep a record of your original eye measurements from this procedure (your doctor can give them to you), in case you need cataract surgery in the future. This is helpful in calculating future implants after cataract surgery. To learn more, see the topic Organizing Your Medical Records.

LASIK is a cosmetic procedure. The cost of refractive surgery varies in different locations, but it can be a significant expense. Most insurance companies do not cover the cost of refractive surgery.

Click here to view a Decision Point.Nearsightedness: Should I Have Laser Surgery?

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  1. Sakimoto T, et al. (2006). Laser eye surgery for refractive errors. Lancet, 367(9520): 1432–1447.


ByHealthwise Staff
Primary Medical ReviewerKathleen Romito, MD - Family Medicine
Specialist Medical ReviewerChristopher J. Rudnisky, MD, MPH, FRCSC - Ophthalmology
Last RevisedJune 24, 2011

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