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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.
Vampire bats have a natural anticoagulant in their saliva that permits continuous bleeding after they painlessly open a wound with their incisors. This capillary blood does not cause any significant blood loss to their victims.
On average, the stomach produces 2 L of hydrochloric acid per day.
The National Institutes of Health have supported research into acupuncture. This has shown that acupuncture significantly reduced pain associated with osteoarthritis of the knee, when used as a complement to conventional therapies.
People with high total cholesterol have about two times the risk for heart disease as people with ideal levels.