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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?
More than 2,500 barbiturates have been synthesized. At the height of their popularity, about 50 were marketed for human use.
Did you know?
On average, the stomach produces 2 L of hydrochloric acid per day.
Did you know?
During pregnancy, a woman is more likely to experience bleeding gums and nosebleeds caused by hormonal changes that increase blood flow to the mouth and nose.
Did you know?
Most childhood vaccines are 90–99% effective in preventing disease. Side effects are rarely serious.