Folding back the top layer and reshaping tissue underneath
LASIK, Laser-Assisted In Situ Keratomileusis, is a refractive laser procedure used to treat nearsightedness, farsightedness, and astigmatism. Since its invention in the early 90s, LASIK has been the most popular surgical treatment method to correct refractive errors. Like other laser eye surgeries, LASIK treats vision defects by reshaping the cornea to correct the way light is focused on the back of the eye.
With LASIK, a surgeon creates a sliver of tissue, essentially making a flap, at the front of the eye to expose the inner layers of corneal tissue to the laser. Surgeons will either use a mechanical instrument, called a microkeratome, or a femtosecond laser, for this step. When a femtosecond laser is used, the procedure is called Femto-LASIK. Once the flap is folded away, an excimer laser shapes the cornea by removing the exposed tissue. The Femto-LASIK/LASIK procedure is completed when the surgeon closes the flap, returning it to its original position.