LASIK << LAY zihk or LAY sihk >> surgery is a medical procedure used to correct certain eye defects that cause imperfect vision. LASIK stands for laser-assisted in situ keratomileusis. Eye defects called refractive errors prevent the eye from properly focusing light to create images. These defects include myopia (nearsightedness), hyperopia (farsightedness), and astigmatism. People who undergo LASIK surgery can reduce or even eliminate dependency on eyeglasses or contact lenses.
During LASIK surgery, a surgeon cuts a thin flap on the surface of the cornea, the clear tissue that covers the eyeball and focuses light onto the retina at the back of the eye. The flap is folded back to expose the underlying corneal tissue. The surgeon applies a beam from a type of laser called an excimer laser to the eye. The excimer laser beam reshapes the cornea so that it can properly focus light. The doctor then carefully lays the flap back over the exposed cornea.
LASIK surgery is not recommended for people who have thin corneas, unstable vision, or certain medical conditions, such as diabetes. Risks associated with LASIK surgery include infection, diminished vision, dry eyes, glare, or seeing rings or “halos” of light around objects.
See also Eye (Defects of the eye).
