Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Refractive surgery is a surgical operation performed to correct refractive errors such as nearsightedness (myopia), farsightedness (hyperopia), astigmatism or presbyopia. This type of eye surgeries is performed in order to improve vision and reduce the need for glasses or contact lenses. Usually refractive errors are treated, reshaping the cornea with a laser. Learn more about the procedure and various techniques employed to improve vision in this book.