Laser in-situ Keratomileusis is a procedure used to correct or reduce moderate to high levels of myopia (between -6 to -15.0 diopters or over +4.5 diopters). In LASIK, the surgeon combines the use of a keratome and the excimer laser to remove a thin layer of tissue from the center of the cornea. By removing the tissue, the central cornea is flattened and myopia is reduced.

First, the surgeon creates a 160 micrometers thick flap in the cornea using a surgical instrument called a microkeratome. Then he uses the laser to remove a micro-thin layer of tissue from the exposed corneal surface. Finally, the flap is replaced without the need for sutures. Usually the operated eye is protected with a contact lense for day or so.