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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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More than 4.4billion prescriptions were dispensed within the United States in 2016.
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About 3% of all pregnant women will give birth to twins, which is an increase in rate of nearly 60% since the early 1980s.
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It is believed that humans initially contracted crabs from gorillas about 3 million years ago from either sleeping in gorilla nests or eating the apes.
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The familiar sounds of your heart are made by the heart's valves as they open and close.