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Astigmatism is the most common vision problem. It may accompany nearsightedness or farsightedness. It is usually caused by an irregularly shaped cornea, but sometimes it is the result of an irregularly shaped lens. Either type can be corrected by eyeglasses, contact lenses, or refractive surgery.
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This year, an estimated 1.4 million Americans will have a new or recurrent heart attack.
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Asthma cases in Americans are about 75% higher today than they were in 1980.
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After a vasectomy, it takes about 12 ejaculations to clear out sperm that were already beyond the blocked area.
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There are more nerve cells in one human brain than there are stars in the Milky Way.