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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.
On average, someone in the United States has a stroke about every 40 seconds. This is about 795,000 people per year.
The heart is located in the center of the chest, with part of it tipped slightly so that it taps against the left side of the chest.
Although puberty usually occurs in the early teenage years, the world's youngest parents were two Chinese children who had their first baby when they were 8 and 9 years of age.
Nearly 31 million adults in America have a total cholesterol level that is more than 240 mg per dL.