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A cataract is a clouding of the eyes' natural lens. As we age, some clouding of the lens may occur. The first sign of a cataract is usually blurry vision. Although glasses and other visual aids may at first help a person with cataracts, surgery may become inevitable. Cataract surgery is very successful in restoring vision, and it is the most frequently performed surgery in the United States.
Over time, chronic hepatitis B virus and hepatitis C virus infections can progress to advanced liver disease, liver failure, and hepatocellular carcinoma. Unlike other forms, more than 80% of hepatitis C infections become chronic and lead to liver disease. When combined with hepatitis B, hepatitis C now accounts for 75% percent of all cases of liver disease around the world. Liver failure caused by hepatitis C is now leading cause of liver transplants in the United States.
It is widely believed that giving a daily oral dose of aspirin to heart attack patients improves their chances of survival because the aspirin blocks the formation of new blood clots.
Malaria was not eliminated in the United States until 1951. The term eliminated means that no new cases arise in a country for 3 years.
Warfarin was developed as a consequence of the study of a strange bleeding disorder that suddenly occurred in cattle on the northern prairies of the United States in the early 1900s.