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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.
The first documented use of surgical anesthesia in the United States was in Connecticut in 1844.
The most common childhood diseases include croup, chickenpox, ear infections, flu, pneumonia, ringworm, respiratory syncytial virus, scabies, head lice, and asthma.
When blood is exposed to air, it clots. Heparin allows the blood to come in direct contact with air without clotting.
Illicit drug use costs the United States approximately $181 billion every year.