In LASIK, topical anesthesia is applied to the surface of the eye. Next, the surgeon makes a thin, tangential cut through the cornea using a femtosecond laser or mechanical microkeratome. The corneal tissue flap that results from this cut, which looks like a contact lens, is hinged on one side. The surgeon retracts the flap and then uses an excimer laser to treat the exposed corneal tissue beneath the flap, thereby changing its shape in a very precise manner. Once this has been accomplished, the flap is placed back into position where it seals down over the next 12 to 24 hours.
Your surgeon can explain the limits of refractive errors that can be treated by LASIK.
Not every patient is a candidate for LASIK. Patients with thin corneas, progressive ectasia, scars, irregular astigmatism, and a few other pathologies are ineligible. Your surgeon, or one of the optometrists in his or her practice, can determine if you are a suitable candidate during a free screening examination.
LASIK typically takes about 20 minutes to perform per eye and both eyes are usually treated during the same session. LASIK is associated with minimal to mild discomfort while it is being performed. When the topical anesthesia wears off, however, the level of discomfort increases. Most patients develop redness and tearing. There is often stinging and a gritty sensation that lasts 6 to 12 hours. Visual recovery is fast. Most patients see fairly well the next day.
As with any procedure, there is a risk of complications with LASIK, including the possibility of an under correction or over correction. The risks should be discussed with your doctor before you undergo the procedure.
Enhancements are usually performed during the early postoperative period by lifting the flap and applying additional excimer laser treatment to the cornea. Late enhancements can be performed by lifting or re-cutting the flap or by photorefractive keratectomy (PRK).