Age-related cataract refers to the clouding of the crystalline lens that occurs in middle-aged and elderly people, and it is the most common blinding eye disease among the elderly, and the prevalence rate increases significantly with age. Cataract blindness not only brings great pain to the life of the elderly, but also brings great burden to the family and society, therefore, it is very important to prevent and treat cataract. For many years, people have been constantly looking for effective drugs to prevent and delay the occurrence and development of senile cataract. However, so far, there are no drugs with certain efficacy at home and abroad. The most effective way to restore sight is still surgery. Through surgery, the vast majority of patients can regain normal vision and lead a normal life. In the 1970s, the most prevalent cataract surgery in China was cryo-extraction. It often brings more complications after surgery, affecting vision and even blindness. In addition, it is necessary to wear highly convex lenses of about 1,000 degrees to replace the crystals removed due to cataract, which is bulky and inconvenient, and has the disadvantages of narrowing the field of vision and distorting the vision, which seriously affects the quality of life. Since the 1980s, cataract surgery has made significant progress due to the application of operating microscopes, microscopic instruments and IOLs. The implantation of artificial lenses has replaced the crystals removed due to cataract, which meets the needs of the physiological conditions of the eye, and there is no need to wear high-convex glasses after the operation, so the effect of restoration of sight has been greatly improved, and the quality of life has been significantly improved. In recent years, the ultrasonic emulsification technique for cataract removal has gradually matured. The operation is performed through a small incision of 2.8~3.2mm, where the ultrasonic emulsification head is inserted into the eye, and ultrasonic waves are used to crush the nucleus of the crystalline lens so that the nucleus is turned into a milky substance and then suctioned out, and then implanted into an artificial lens. This advanced ultrasonic emulsification technology makes cataract surgery more delicate, safer, less damaging, lighter astigmatism, faster recovery, and better efficacy. The procedure is convenient, does not require hospitalization, and can be completed in about 10 minutes on an outpatient basis. So, when to do cataract surgery? Traditional cataract surgery, the appropriate time for cataract development to near maturity or maturity stage, the lens is largely or completely cloudy, the patient’s vision can only distinguish between the index in front of the eyes or manual before surgery. It is not difficult to imagine that during a long period of time waiting for the surgery, the patient suffers from the pain of poor vision, the quality of life is significantly reduced, and even lose the ability to work, and it is difficult to live a fully self-managed life. With the increasing improvement of living standards, people’s demand for quality of life is also higher and higher. In the cataract surgery methods and technology level continues to develop today, many cataract surgeons have put forward the view that the elderly cataract should be operated as early as possible. This is because the sooner the elderly are operated on, the sooner they can gain sight, improve their quality of life and be better engaged in their work. Moreover, the longer the surgery is delayed, the higher the degree of clouding of the lens and the harder the nucleus of the lens, the more difficult and risky the surgery will be. In addition, as the surgery is delayed, the patient gets older, his/her general health condition becomes poorer, and the chances of cardiovascular and cerebrovascular diseases increase or worsen, which also increases the systemic risk of the surgery. Of course, as different patients have significantly different vision requirements. Therefore, it is difficult to accurately determine a vision standard to decide whether or not to operate. However, it is certain that when cataracts cause vision loss and affect work and study, surgery can be performed even if the cataracts have not matured. Since corrected visual acuity of less than 0.3 makes the eye a low vision eye, many doctors consider corrected visual acuity ≤ 0.3 as the time for surgery. In special cases, some visual acuities ≤ 0.5 are amenable to surgery. It is worth mentioning that no matter when the surgery is performed, the patient’s requirements for vision and the patient’s interests should be taken into account, as well as the condition of the hospital’s equipment and the doctor’s skill level.