Cataract refers to a chronic eye disease in which the lens becomes cloudy, vision slowly decreases, and eventually leads to blindness. Because a round silvery-white or brownish-brown cataract eventually appears in the pupil, the "Secret Eye Medicine Longmu Lun" calls it cataract. This disease is more common in the elderly. It often occurs in both eyes, but there are differences in the occurrence of the disease in sequence or the severity. There are more than ten types of diseases similar to this disease recorded in ophthalmological literature of various dynasties, such as floating cataract, sinking cataract, slippery cataract, jujube flower cataract, yellow heart white cataract, and silver cataract. Although the names are different, they are all turbidity of the lens, but the stage, degree, location, and color of the lesions are different. When the cataract of this disease is old, surgical treatment can restore a certain degree of vision. It is equivalent to senile cataract in Western medicine.