Age-related cataract refers to the opacity of the lens that begins to occur in middle-aged and elderly people. The prevalence increases significantly with age. Because it mainly occurs in the elderly, it was previously called senile cataract. Its occurrence is related to many factors such as environment, nutrition, metabolism and genetics. All kinds of reasons such as aging, genetics, local nutritional disorders, immune and metabolic abnormalities, trauma, poisoning, radiation, etc. can cause lens metabolism disorders, leading to lens protein denaturation and turbidity, which is called cataract. At this time, the light is blocked by the turbid lens and cannot be projected on the retina, so objects cannot be seen clearly. From the perspective of group blindness prevention and treatment, the World Health Organization classifies the lens as denatured and turbid, becoming opaque, and affecting vision, and those with corrected vision of 0.7 or below as cataracts.