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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?
There are over 65,000 known species of protozoa. About 10,000 species are parasitic.
Did you know?
Approximately 500,000 babies are born each year in the United States to teenage mothers.
Did you know?
There are more nerve cells in one human brain than there are stars in the Milky Way.
Did you know?
Excessive alcohol use costs the country approximately $235 billion every year.