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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.
The eye muscles are the most active muscles in the whole body. The external muscles that move the eyes are the strongest muscles in the human body for the job they have to do. They are 100 times more powerful than they need to be.
The familiar sounds of your heart are made by the heart's valves as they open and close.
Eat fiber! A diet high in fiber can help lower cholesterol levels by as much as 10%.
Vaccines prevent between 2.5 and 4 million deaths every year.