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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.
In inpatient settings, adverse drug events account for an estimated one in three of all hospital adverse events. They affect approximately 2 million hospital stays every year, and prolong hospital stays by between one and five days.
Human stomach acid is strong enough to dissolve small pieces of metal such as razor blades or staples.
After a vasectomy, it takes about 12 ejaculations to clear out sperm that were already beyond the blocked area.
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.