Chronic ultraviolet(UV) radiation is considered to be important reason of the senile cataract formation.A large number of epidemiological investigations have shown that cortical and mixed cataracts are subjected to UV radiation.10% to 30% relative risk can be attributed to solar radiation.UV radiation,particularly UVB is an important risk factor for cortical cataract.The lens epithelial cells is not only the most active part of the lens metabolism,but also an important target tissue for UV.The over-apoptosis of lens epithelial cells and the damage of lens protein are closely relevant to the occurrence and development of cataract.