Chances are you have probably heard of LASIK eye surgery unless you have been living under a rock for the past 20 years. LASIK stands for Laser-Assisted In Situ Keratomileusis and is the best known and most commonly performed procedure to correct vision problems so you no longer need to wear eyeglasses or contact lenses.
LASIK is refractive surgery that actually changes the shape of your cornea. This is done to correct your vision. The retina is a layer at the back of the eye which contains cells that are sensitive to light. In a normal eye images are in clear focus due to the light rays being properly bent but when the light rays are not properly bent the light ends up being focused elsewhere which results in blurry vision.
Traditionally contact lenses or glasses have been used to refract or bend the light rays and how that is accomplished is based upon weather you have hyperopia or myopia. These are the fancy words for being farsighted or nearsighted.