Causes of Cataracts: It's not precisely understood why people get cataracts. Aging is a known risk factor (ARC) Others include: Smoking Excessive use of alcohol Diabetes Trauma to the eyes Extended use of corticosteroids Prolonged radiation or sun exposureIt’s not precisely understood why people get cataracts. Aging is a known risk factor (ARC). Others include: Smoking Excessive use of alcohol Diabetes Trauma to the eyes Extended use of corticosteroids Prolonged radiation or sun exposure Causes of Cataracts: