Cataracts are most commonly caused by the clouding of the crystalline lens as we age. Age related cataracts form due to a buildup of protein on the lens. Cataracts may cause light sensitivity, difficulty seeing at night, loss of color intensity, halos around lights, and frequent changes in eyeglass prescriptions. As cataracts mature, vision becomes increasingly impaired.
The picture below shows an example of how cataracts can manifest.