LASIK
stands for Laser-In-Situ-Keratomileusis, which means "to shape the cornea from within using the laser." Nearsightedness and farsightedness occur because the cornea is too steep or too flat. Therefore, the light that enters the eye is bent by the cornea either too much (in myopia) or not enough (in hyperopia). When light does not focus directly onto the back of the eye (the retina) your vision is blurry.
How Does LASIK Fix This?
During LASIK the laser is used to change the shape of the cornea so that the light entering the eye focuses on the retina, giving you clear vision. The too steep cornea is flattened by the laser in myopes, and the too flat cornea is steepened by the laser in hyperopes.