People with diabetes are predisposed to cataracts. Sorbitol, a byproduct of excess glucose, can accumulate within the lens, attracting water and clouding the lens. People with diabetes develop cataracts at a younger age than persons without diabetes. When cataracts appear, they quickly progress. Cataracts may also be associated with aging, genetic factors, smoking, hypothyroidism, exposure to radiation or ultraviolet sunlight, retinal detachment, electrical shock, eye trauma, glaucoma surgery, and long-term corticosteroid use.