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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.
Did you know?
This year, an estimated 1.4 million Americans will have a new or recurrent heart attack.
Did you know?
On average, the stomach produces 2 L of hydrochloric acid per day.
Did you know?
The horizontal fraction bar was introduced by the Arabs.
Did you know?
More than nineteen million Americans carry the factor V gene that causes blood clots, pulmonary embolism, and heart disease.