in-situ keratomileusis (LASIK) is a method
of vision correction which uses the excimer
laser to precisely remove corneal tissue from
beneath a protective corneal flap. By removing this
tissue, the curvature of the cornea, and therefore its
focusing power, is changed. Myopia or nearsightedness,
hyperopia or farsightedness, and astigmatism can be
corrected with LASIK.