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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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The human body produces and destroys 15 million blood cells every second.
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The most destructive flu epidemic of all times in recorded history occurred in 1918, with approximately 20 million deaths worldwide.
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People about to have surgery must tell their health care providers about all supplements they take.
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More than 150,000 Americans killed by cardiovascular disease are younger than the age of 65 years.