The eye is one of the most radiation sensitive organs. Laboratory studies show that chronic UVB exposure is a major factor of cataract formation. This occurs over time due to absorbed UV radiation by the lens in the eye. Specifically, a photochemical process occurs, causing denaturation of the lens proteins. As the lens becomes more opaque, blindness results.
Cataract formation is the major preventable cause of blindness worldwide.
People in tropical areas and young children are most susceptible. The reason of child susceptibility is due to their less well developed pigmentation of the eye. Exposure of the eye to UV can also induce melanoma of the eye and photokeratitis. Photokeratitis is also known as sun blindness or welder's flash, and is basically a painful burn on the surface of the eye. Protection from these disorders is via sunglasses, although ironically exposure to the UV radiation may be enhanced by sunglasses that poorly absorb UV because the pupil opens wider to compensate for the reduced visible light.