LASIK is the acronym for laser in situ keratomileusis, sometimes referred to as laser-assisted in situ keratomileusis. The name refers to the use of a laser to reshape the cornea without invading the neighboring cell layers. In situ is Greek for "in the natural or normal place." Medically, in situ means confined to the site of origin without invasion of neighboring tissues. Kerato is the Greek word for cornea and mileusis means "to shape."
LASIK is a type of refractive eye surgery that may reduce a person's dependency on glasses or contact lenses by permanently changing the shape of the cornea (the delicate clear covering on the front of the eye).
Refractive eye surgery is a surgical procedure that changes the way the eye refracts light. As light rays enter the eye, the cornea and lens bend (refract) the rays to focus them on the back of the eye, the retina. If a patient has a refractive error, the eye is shaped in such a way that light rays are not sharply focused on the retina.
The cornea is the part of the eye that helps focus light to create an image on the retina. Usually the shape of the cornea and the eye are not perfect and the image on the retina is out-of-focus (blurred) or distorted. These imperfections in the focusing power of the eye are called refractive errors.
There are three primary types of refractive errors: myopia, hyperopia and astigmatism. Persons with myopia, or nearsightedness, have more difficulty seeing distant objects as clearly as near objects. Persons with hyperopia, or farsightedness, have more difficulty seeing near objects as clearly as distant objects. Astigmatism is a distortion of the image on the retina caused by irregularities in the cornea or lens of the eye. Combinations of myopia and astigmatism or hyperopia and astigmatism are common. LASIK surgery is most commonly used to correct myopia.
LASIK eye surgery was developed in 1990 by doctors Lucio Buratto and Ioannis Pallikaris. It is a refinement of an earlier procedure, photorefractive keratotomy (PRK), which also uses ultraviolet laser light to disrupt tissue in the cornea for removal or reshaping to achieve sharper vision. LASIK has been performed internationally for approximately ten years. It was first performed in clinical trials in the United States in 1995. The United States Food and Drug Administration provides a complete listing of the approval status of excimer lasers in the US on their LASIK website.
Astigmatism, cornea, excimer laser, eye surgery, hyperopia, laser-assisted in situ, laser epithelial keratomileusis, laser vision correction, LASIK, keratomileusis, myopia, photorefractive keratotomy (PRK), refractive eye surgery, refractory surgery, vision correction.