lasik (laser in-situ keratomileusis) for nearsightedness

surgery overview

lasik (laser in-situ keratomileusis) is a surgery that flattens the cornea. it's 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. it doesn't damage nearby tissues.

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

what to expect

after surgery, you may wear a patch or contact lens on the eye. you will also get instructions on how to manage your pain. someone must drive you home and then back to the surgeon's office the next day. during this second visit, the surgeon will check 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.

• your eye will feel irritated and scratchy 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.
• avoid vigorous sports, eye makeup, and activities that may get water in the eye for as long as your doctor recommends. you should shower before the surgery and then avoid showering for a day or two afterward.

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.

why it is done

lasik surgery may be used to correct mild to moderate nearsightedness in otherwise healthy eyes. it's also thought to be the best procedure for correcting high nearsightedness (greater than 7 dioptres). but the results of surgery become harder to predict with higher amounts of nearsightedness.

how well it works

over the short term, lasik has been shown to work very well to reduce 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 dioptres, studies showed that after surgery, about:^{footnote 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 dioptres, studies showed that after surgery, about:^{footnote 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.

doctors continue to improve the technique and to study the long-term results.

risks

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 caused by inflammation during healing). this usually goes away on its own. but your doctor may give you medicine or do a procedure to relieve the inflammation.
• night vision problems, such as halos. (these are often described as a shimmering circle around light sources such as headlights or street lamps.)
• glare, or being more sensitive 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. (this is the best possible vision you can achieve using glasses or contact lenses.)
• overcorrection or undercorrection.

serious vision-threatening complications are rare but may include:

• infection of the cornea (keratitis).
• elevated pressure inside the eye (intraocular pressure) leading to glaucoma.