|
|
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.
Blood is approximately twice as thick as water because of the cells and other components found in it.
Not getting enough sleep can greatly weaken the immune system. Lack of sleep makes you more likely to catch a cold, or more difficult to fight off an infection.
Nearly 31 million adults in America have a total cholesterol level that is more than 240 mg per dL.
Most childhood vaccines are 90–99% effective in preventing disease. Side effects are rarely serious.

