Surgical refractive procedures now make it possible to permanently eliminate or significantly reduce the need to wear glasses or contact lenses, even for people who require thick corrective lenses. Appropriate surgery can modify the eye to focus light rays properly on the retina. Various operations can reduce or correct nearsightedness, farsightedness, astigmatism, and more. Newly developed intraocular lenses can even correct presbyopia—the reduced ability to focus from far to near that most people begins to experience in their forties.
There are two basic types of corrective refractive surgery. One changes the curvature of the cornea (outer surface of the eye). The other changes the internal optics of the eye, either by replacing the natural lens of the eye or by using an intraocular lens in addition to the natural lens.
American Academy of Ophthalmology