Nearsightedness (Myopia)

Feeling a little flat? Things a little unfocused? Twenty-five percent of all Americans have the eye condition called myopia--commonly known as nearsightedness. It runs in families, and females and males are equally affected.

When you are myopic, the globe of your eye is not shaped like it should be for optimal vision. Instead it is flattened out, making it too long from front to back. This causes a problem in focusing--what eye-care specialists refer to as a "refractive" defect.

When light rays enter the eye, they are bent by the cornea (lens) and focused on the back of the eye (retina). When the eyeball is flattened, however, light from faraway objects focus in front of the retina, rather than on it. That makes them blurry. If you are nearsighted, you will need to hold reading materials close to your eyes to see them, and to sit up close to the television or computer screen. Usually nearsightedness appears by school age, so children may have trouble seeing the blackboard.

Eyeglasses or contact lenses easily correct the problem by refocusing the image on the retina. They do so with a concave lens that is shaped to compensate for the exact vision defect.

In recent years, eye surgery has also become an option for correcting nearsightedness. LASIK, which stands for "laser in situ keratomileusis," has been performed in the United States since the early 1990s. It uses a tiny laser beam to "shave" off a minute amount of eye tissue to correct the vision

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