If the lens in the eye becomes cloudy, a cataract will form and vision will be significantly impaired. The current effective treatment is cataract surgery, but the surgery requires that the posterior capsule of the lens be preserved so that an IOL can be placed. After cataract surgery, the remaining lens epithelial cells in the posterior capsule can migrate to the posterior capsule and proliferate and differentiate, creating new lens fibers or fibrosis, leading to the formation of posterior cataract. The current effective treatment is to use YAG laser to perform posterior capsulotomy. After treatment, IOP should be monitored closely to prevent high IOP after treatment. The floating black dots in front of the eyes after treatment are usually not necessary, but if the floating black dots significantly affect the vision, immediate medical attention should be sought.