Various causes, such as aging, genetics, local nutritional disorders, immune and metabolic abnormalities, trauma, poisoning, radiation, etc., can lead to metabolic disorders of the lens, causing the denaturation of lens proteins and resulting in cloudiness; this is called cataract. Cataracts can be divided into congenital and acquired. Congenital cataracts, also known as developmental cataracts, are divided into anterior polar cataracts, posterior polar cataracts, nuclear cataracts, and total cataracts. Acquired cataracts are divided into senile cataracts, complicated cataracts, traumatic cataracts, metabolic cataracts, radiation cataracts, and those related to medications and poisoning.