With the LASIK method, the correction of the refractive anomaly is not done on the surface but inside the cornea. Initially, a thin surface flap of corneal tissue is created, which is not completely cut off but remains attached to the cornea on one side. It is then lifted, revealing the inner layers of the cornea and the Excimer Laser is applied, which achieves sublimation of the corneal tissue, in order to change the curvature of the cornea and correct the refractive error. Finally, the surgeon repositions the flap.

The way in which the flap is created in recent years has evolved into a process of high precision. Until a few years ago, the incision was made only with the use of a mechanical microkeratome (with a blade), which cut the cornea.