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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.
After a vasectomy, it takes about 12 ejaculations to clear out sperm that were already beyond the blocked area.
Your heart beats over 36 million times a year.
The immune system needs 9.5 hours of sleep in total darkness to recharge completely.
In 2012, nearly 24 milliion Americans, aged 12 and older, had abused an illicit drug, according to the National Institute on Drug Abuse (NIDA).