As the pace of life accelerates and the amount of information increases, the proportion of myopic people is getting higher and higher. At present, according to the preliminary survey of the research project on the prevention and treatment of myopia in children conducted by China, the United States and Australia, the incidence of myopia in our population is 33%, and the number of myopic eyes in the country is nearly 400 million, which is 1.5 times of the world average (22%). The prevalence of myopia among adolescents, a group with a high prevalence of myopia, is as high as 50 to 60 percent. China has become one of the countries with the highest prevalence of myopia in the world, and the number of myopic eyes is the highest in the world. Myopia can be divided into mild, moderate and high myopia according to the degree. Usually 3.00D (300 degrees) or less is called mild myopia; 3.00D ~ 6.00D (300 degrees ~ 600 degrees) is moderate myopia; 6.00D (600 degrees) or more is accompanied by eye axis prolongation, fundus retina and choroidal atrophy and other degenerative pathologies as the main characteristics of refractive error for high myopia, also known as pathological myopia. High myopia is prone to many serious complications and even blindness, and is one of the common causes of blindness in adults, accounting for 10% to 20% of myopia in China and ranking 6th in terms of blinding diseases. Common symptoms and complications of high myopia Clinically, in addition to poor distance vision, high myopia usually has symptoms such as poor night vision, flying mosquitoes, floating objects in front of the eyes, flashing lights, etc. It is also accompanied by degenerative pathologies such as prolongation of the eye axis, retinal and choroidal atrophy in different degrees, and the risk of retinal detachment, macular hemorrhage and neovascularization is much higher compared to normal people. The main complications of high myopia are cataract, glaucoma, posterior scleral chylomalacia, retinal atrophic degeneration, hemorrhage and fissure, and retinal detachment. Causes of high myopia prone to complications of cataracts Myopia (especially high myopia) is a cause of early-onset cataracts and a high incidence cause. The Ministry of Health’s Myopia Focused Laboratory has shown that less than 10% of cataracts are caused by high myopia, but currently about 39% of cataracts are caused by high myopia, which means that on average, 4 out of every 10 cataract patients have high myopia. Although this figure is unbelievable, it shows that high myopia is indeed more prone to cataract complications. The main reason why high myopia is prone to cataracts is because of the abnormal nutrient metabolism in highly myopic eyes, which leads to changes in the permeability of the lens capsule membrane, the gradual clouding of the lens due to nutrient disorders and metabolic malfunction, and the gradual loss of vision, resulting in complications of cataracts. This type of cataract is characterized by early onset and slow development, mild to moderate clouding of the lens, mainly nuclear clouding and posterior capsule clouding, and in some patients, the clouding is very significant with brown, tan or even black lens and may be accompanied by relaxation of the suspensory ligament or incomplete dislocation of the lens. As with other cataract treatments, surgery is the only effective treatment for high myopia cataracts, which are often treated by cataract ultrasonic emulsion extraction combined with IOL implantation. However, patients with high myopia have longer eye axes and fragile lens suspensory ligaments, and the chance of postoperative posterior capsule rupture and retinal detachment is slightly higher than that of patients with normal eye axes, especially in older patients with long eye axes. Therefore, the surgical treatment of high myopia with cataract should pay attention to the following two aspects: (1) For patients, it is important to get out of the misconception that “high myopia has problems in the fundus and should not be treated surgically” and to achieve “early detection and early treatment” of cataract complications. This can not only reduce the occurrence of complications, but also achieve safe, convenient and low-cost treatment of high myopia by implanting suitable crystals to treat cataract at the same time. (2) For doctors, they need to accurately measure the patient’s eye axis, understand the patient’s lens, vitreous and fundus before surgery, and fully communicate with the patient and family to have reasonable expectations of the postoperative effect; they should operate delicately during surgery to reduce the damage to the capsule and suspensory ligament, etc.; they should recommend the patient to have regular fundus examination after surgery, and explain in detail the postoperative precautions. Patients with high myopia, especially super high myopia, have much thinner corneas than normal people and are no longer suitable for vision correction through laser keratomileusis, so implanting an IOL with a certain number of degrees will be the only way to treat and correct high myopia at present. This is done by implanting an IOL in the anterior chamber (or posterior chamber) of the patient’s crystalline eye to maintain the natural adjustment function of the lens while adjusting the refraction. Clinical studies have shown that in the treatment of cataracts complicated by high myopia, ultrasonic cataract extraction combined with human folding IOL implantation has the advantages of small incision, low corneal astigmatism, high safety, good predictability, fast postoperative healing, and few complications. Moreover, it can treat high myopia that has plagued patients for years while removing the cataract by ultrasound emulsification, because the implanted IOL already has a specific degree equivalent to the effect of glasses. This two-in-one treatment reduces the pain of secondary surgery and saves some of the cost of treatment.