Anterior subcapsular and cortical cataracts occurred in most mice.

Cortical cataracts are due to opacification of the lens cortex (outer layer).

The cataract linked to ultraviolet exposure is the cortical cataract and forms in the outer layer of the lens.

"Our data suggest that for every 10 percent increase in ultraviolet B radiation, there will be a 6 percent increase in cortical cataracts," he said.

Myotonic dystrophy patients may have a cortical cataract with a blue dot appearance, or a posterior subcapsular cataract.

Studies are suggestive of an association between ocular cortical cataracts and UV-B exposure, using crude approximations of exposure and various cataract assessment techniques.

Nuclear cataracts, to which cigarette smoking was found to contribute, form in the center of the lens, while the most common type, cortical cataracts, occur in the periphery of the lens and impair sight less often.

American Journal of Epidemiology: "Model of Risk of Cortical Cataract in the US Population with Exposure to Increased Ultraviolet Radiation due to Stratospheric Ozone Depletion."

"If you think of the lens as a peach, nuclear cataracts involve the stone of the peach, cortical cataracts involve the flesh, and posterior subcapsular cataracts involve the skin," Dr. Taylor said.