Excimer laser keratomileusis is a procedure that corrects refractive error by removing a certain thickness of corneal tissue through laser cutting and changing the shape of the cornea (flattening or steepening). The excimer laser currently used in laser myopia surgery photochemically vaporizes the cornea, but has no effect on the surrounding tissue. The excimer laser used to treat myopia is a “cold laser” that does not burn the eye, is weakly penetrating, cuts only 0.25um per pulse, and is very precise, does not penetrate the human cornea, and does not damage the fundus.