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(Laser-Assisted In Situ Keratomileusis)

En Español (Spanish Version)

Click here to view an animated version of this procedure.


LASIK is a surgery that uses a laser to reshape the cornea of the eye. This reshaping changes focusing power and usually corrects vision. Surgery may be performed on both eyes, either at the same time or on separate occasions.

Cornea of the Eye

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Parts of the Body Involved

LASIK is performed on the cornea of the eye.

Reasons for Procedure

LASIK is done in hopes of eliminating the need for glasses or contact lenses.

Risk Factors for Complications

  • Pre-existing eye disease (such as glaucoma ) or abnormalities in the shape of the cornea (such as keratoconus)
  • Persistent eye infections (such as blepharitis )
  • Dry eyes
  • Autoimmune disease (such as rheumatoid arthritis or lupus ), immunodeficiency, and other conditions or use of medications that alter wound healing
  • Changing eyesight due to medication use or medical conditions (such as pregnancy or breast-feeding)
  • Diabetes
  • Any other form of fluctuating vision

What to Expect

Prior to Procedure

Your doctor will likely do the following:

  • Complete eye exam
  • Review of medications

In the days leading up to your procedure:

  • It is best to stop wearing your contact lenses at least 2 to 4 weeks before your preoperative eye evaluation and surgery. The length of time depends on the type of contact lenses and your surgeon’s preference.
  • Arrange for a ride to and from the procedure.
  • Do not wear lotion, cream, make-up, or perfume the day before or day of surgery.
  • You may be asked to scrub your eyelashes and/or use eye drops before the surgery.

During Procedure

Topical anesthesia (numbing eye drops) will be applied. A sedative may be given as well.


Drops are given to numb the surface of the eye. You may be given an oral sedative.

Description of the Procedure

You are positioned on your back in a reclining chair. The area surrounding your eye is cleaned, numbing drops are given, and the eyelid is held open with a special device. A ring is placed on the eye and pressure is applied to create suction. A blade is then attached to the suction ring. The doctor uses the blade to cut a flap in the cornea, and the ring and blade are removed. The doctor folds back the flap.

You look into a light (not the laser). The doctor directs the laser to remove a specific amount of corneal tissue. The laser makes a ticking sound as it reshapes the cornea. At this point, some patients report a smell similar to burning hair. Once the laser is finished, the corneal flap is gently placed back into position, antibiotic drops are put into the eye, and a shield is placed over the eye. Your doctor will likely remove this shield at your first visit, which is usually the day after your surgery.

There are other ways to perform laser vision correction surgery. One includes using a laser to make the flap in the cornea. The other includes removing the top layer of the cornea with a special device or chemical, and then performing the laser, without ever making a flap. Ask your doctor which procedure is best for you.

After Procedure

You'll wear a shield to protect your eye from injury or pressure, even while sleeping.

How Long Will It Take?

The procedure takes less than 30 minutes.

Will It Hurt?

You'll likely feel some discomfort when the suction ring is applied. And just after the procedure, expect a burning or itching sensation, or the feeling that there is a foreign object in your eye. Your eye may tear, and may be red and bloodshot. You will most likely have a loss of vision at times during the procedure, which is normal.

Possible Complications

LASIK eye surgery has a relatively low complication rate, but they can occur. Possible complications include, but are not limited to:

  • Infection
  • Under-or over-correction of the refractive error
  • Scarring
  • Fuzzy or blurry vision
  • Poor night vision
  • Seeing halos or sunbursts around light/glare
  • Long-term dryness, scratchiness, or pain
  • Correction may not last
  • The corneal flap may become dislodged
  • Permanent decrease or loss of vision that cannot be corrected with glasses nor contact lenses
  • Need for additional laser or surgery

Average Hospital Stay

There is no hospital stay required for this procedure.

Postoperative Care

  • Do not rub your eyes.
  • Vision may be hazy or cloudy; you may see starbursts or halos around lights.
  • Take pain medication as recommended by your doctor.
  • Use eye drops prescribed by your doctor to prevent infection and decrease inflammation.
  • Do not put a contact lens or anything else in the operative eye unless instructed by your surgeon.
  • Do not use cream, lotion, or make-up near the eye until allowed to do so by your ophthalmologist (usually at least two weeks).


Vision changes and redness should gradually improve over several days. However, it may take up to six months for your vision to completely stabilize. Your doctor will schedule follow-up visits.

Your physician will tell you when you are allowed to return to normal activities. Most people can return to work within several days, once cleared by their ophthalmologist. Patients can often return to noncontact sport activities within several days but must avoid strenuous contact sports for at least several weeks. Do not swim or sit in a hot tub or whirlpool until cleared by your doctor (usually at least 1 to 2 months).

Additional surgery may be necessary to further correct or enhance vision. If more surgery is needed, wait until your eyesight has stabilized. It is usually considered to be stable when you have consistent measurements on at least two consecutive exams several months apart.

Most people who get LASIK will still need reading glasses at middle age and beyond to correct for presbyopia (decreased ability to focus due to age). Be sure to discuss presbyopia with your doctor prior to getting LASIK so that you understand how it will affect your vision.

Call Your Doctor Immediately If Any of the Following Occurs

  • Pain
  • Vision worsens
  • Signs of infection, including fever and chills
  • Redness, swelling, increasing pain, bleeding, or discharge from the eye
  • Any other problems or concerns


Eye Surgery Education Council

LASIK Surgery
US Food and Drug Administration


Health Canada


American Academy of Ophthalmology website. Available at: .

US Food and Drug Administration (FDA) website. Available at: .

Last reviewed March 2008 by Alexander J. Anetakis, MD

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.

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