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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?
The average adult has about 21 square feet of skin.
Did you know?
The ratio of hydrogen atoms to oxygen in water (H2O) is 2:1.
Did you know?
It is believed that humans initially contracted crabs from gorillas about 3 million years ago from either sleeping in gorilla nests or eating the apes.
Did you know?
Today, nearly 8 out of 10 pregnant women living with HIV (about 1.1 million), receive antiretrovirals.