LASIK is a procedure that is used to correct refractive errors in the eye. Refractive errors are imperfections in the eye’s focusing power, and the procedures used to correct them are, as a group, called refractive surgery. LASIK is one type of refractive surgery. In LASIK, a special laser is used to remove corneal tissue, reshaping the cornea in order to improve its focusing power.
There are three types of refractive errors. These include: astigmatism, hyperopia, and myopia. Astigmatism is a distortion of the image on the retina caused by irregularities in the cornea or lens of the eye. Hyperopia, more commonly known as farsightedness, causes people to have more difficulty seeing objects that are nearer to them, as opposed to objects that are farther. Myopia, or nearsightedness, causes the exact opposite effect. Shortsighted people have a hard time seeing objects that are farther off. Combinations of astigmatism and shortsightedness and astigmatism and farsightedness are quite common, and most people use contact lenses to compensate for these imperfections.
There are also three types of refractive surgery. Aside from LASIK, there is Radial Keratotomy (RK), and Photorefractive Keratectomy (PRK). In RK, an exceptionally sharp knife is used to change the shape of the cornea. The aim of a PRK procedure is to re-shape the cornea as well, but it uses a laser to do achieve this effect. LASIK is quite similar to PRK in this regard. The only difference lies in the how they treat the stroma. In a PRK procedure, the top layer of the cornea is scraped away to expose the stromal layer underneath. In contrast, in a LASIK procedure a flap is cut in this layer and the flap is folded back.
Jeanette Pollock is a freelance author and website owner of eye-care-hq.com . Visit Jeanette's site to learn more about LASIK eye surgery .