Geriatric cataract is the most common eye disease among the elderly and the number one cause of blindness in China. Currently, the main treatment method is surgery to surgically remove the cloudy lens and implant an artificial lens to improve vision. Since cataract surgery is an elective surgery, many elderly people are confused about the timing of surgery. Some people say that cataracts should be opened when they can no longer see, while others say that it is better to open cataracts earlier, so what kind of timing should be chosen for surgery? The later the stage, the harder the cataract nucleus will be. Before the popularization of cataract ultrasound emulsification, the main method of cataract surgery was called ECCE, which required the complete delivery of the nucleus of the lens. If we compare the nucleus of the lens to a piece of tofu, the mature nucleus is like a piece of frozen tofu because it is harder and can be easily removed completely, while the immature nucleus is softer, like young tofu, and cannot be easily removed. Therefore, the old view was that cataracts should be opened only when they are mature. Nowadays, the method we use for cataract surgery is called cataract ultrasound emulsification, which uses an ultra-emulsifying tip to enter the eye, crush and emulsify the nucleus in the eye, and then suck it out. Therefore, the current view is that cataract does not need to wait until you can’t see and then open. In general, cataract surgery can be performed when the corrected visual acuity is lower than 0.4.