To obtain clear vision when light enters the eye from the outside, it must focus directly on the center of the retinal or fovea. If light falls anywhere except the fovea, there is a refractive error. If light focuses in front of the fovea, there is myopia or nearsightedness. If light focuses behind the fovea, there is hypopia or farsightedness. Astigmatism scatters the light at a certain angle. Glasses, contact lens or LASIK helps to move the out-of-focus light back onto the fovea using optics.