What are the main causes and risk factors of cataract?

Age. Age, as you get older cataracts develop. Other causes can be trauma, steroid usage, prior eye surgery, genetics. Risk factors are UV sun exposure, steroids, smoking.
Risks for cataracts. Cataract cause: Cataract occur from change in lens proteins which cause whitening/clouding of clear lens composition: can be due to an infection or inflammation from birth (ie, rubella), old age/genetics, steroid use, trauma, poor diet; smoking & Diabetes increases risk. More info: eyedoc2020@blogspot.com.
Aging. Most cataracts develop slowly as a result of aging. They may occur more rapidly in people with a history of an eye injury, uveitis or diabetes. Some are associated with genetic diseases. Cataracts can also occur as a side effect of radiation therapy or steroid drugs.