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Did you know?
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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It is difficult to obtain enough calcium without consuming milk or other dairy foods.
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The immune system needs 9.5 hours of sleep in total darkness to recharge completely.
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A seasonal flu vaccine is the best way to reduce the chances you will get seasonal influenza and spread it to others.