Laser assisted in situ keratomileusis, or LASIK, is a refractive procedure that uses an automated blade and a laser to permanently reshape the cornea. The reshaped cornea helps focus light directly onto the retina to produce clearer vision.

LASIK is usually performed as an outpatient procedure using topical anesthesia with drops. The procedure itself generally takes about fifteen minutes. The surgeon creates a flap in the cornea with a microkeratome. The flap is lifted to the side and the cool beam of the excimer laser is used to remove a layer of corneal tissue. The flap is folded back to its normal position and sealed without sutures. The removal of corneal tissue permanently reshapes the cornea.

A shield protects the flap for the first day and night. Vision should be clear by the next day. Healing after surgery is often less painful than with other methods of refractive surgery since the laser removes tissue from the inside of the cornea and not the surface. If needed, eyedrops can be taken for pain and usually are only needed up to one week.

Some people experience poor night vision after LASIK. The surgery may result in undercorrection or overcorrection, which can often be improved with a second surgery. More rare and serious complications include a dislocated flap, epithelial ingrowth and inflammation underneath the flap. Most complications can be managed without any loss of vision. Permanent vision loss is very rare.

The ideal candidate for LASIK has a stable refractive error within the correctable range, is free of eye disease, is at least eighteen years old and is willing to accept the potential risks, complications and side effects of LASIK.