A cataract is a clouding of the lens, an area just behind your eye pupil. The lens works like a camera by focusing the incoming light onto the retina.
Age is definately a major factor in devfeloping cataracts. Nobody want to avoid aging! So far it is unclear why, as we grow older, the protein starts to clump in the lens. Of course not everyone experiences having cataracts, so to just write it down to age is not correct.
Many studies suggest that exposure to ultraviolet light is associated with the development of cataracts. This is one of the reasons why many eyecare specialists recommend wearing sunglasses and a wide brimmed hat. A 2005 study conducted in Iceland suggests that airline pilots have a higher risk of developing nuclear cataract than non-pilots, and that the cause may be exposure to cosmic radiation. A similar theory suggests that astronauts, too, are at risk from cosmic radiation.
It has also been suggested that people with diabetes or people who use steroids, diuretics and major tranquilizers are at risk for developing a cataract.
Other risk factors are: cigarette smoke, air pollution and heavy alcohol consumption. Several studies found lead exposure to be a risk factor. However this research was not extensive enough to determine whether lead can definitely put you at risk, and if so, whether the risk is from a one-time dose at a particular time in life or from chronic exposure over years.