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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?
Human kidneys will clean about 1 million gallons of blood in an average lifetime.
Did you know?
In 1844, Charles Goodyear obtained the first patent for a rubber condom.
Did you know?
Everyone has one nostril that is larger than the other.
Did you know?
The first oncogene was discovered in 1970 and was termed SRC (pronounced "SARK").