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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.
In 1844, Charles Goodyear obtained the first patent for a rubber condom.
More than 2,500 barbiturates have been synthesized. At the height of their popularity, about 50 were marketed for human use.
Most fungi that pathogenically affect humans live in soil. If a person is not healthy, has an open wound, or is immunocompromised, a fungal infection can be very aggressive.
The Romans did not use numerals to indicate fractions but instead used words to indicate parts of a whole.