High myopia is a refractive error characterized by myopia greater than 400-600 degrees, with prolongation of the eye axis and degenerative lesions such as retinal and choroidal atrophy in the fundus of the eye. The etiology and pathogenesis of high myopia and its treatment and prevention are different from those of general myopia. In China, high myopia is autosomal recessive. It is characterized by the onset of myopia in children of preschool age, a progressive increase in myopia, and a progressive increase in retinal chorioretinopathy in the fundus of the eye, resulting in many serious complications. Therefore, high myopia is also known as pathological myopia, malignant myopia, degenerative myopia, progressive myopia, and genetic myopia. The prevalence of high myopia in the population is high, about 1%. High myopia can have many serious complications, most of which can lead to blindness, and is one of the common causes of blindness in adults, accounting for the sixth highest number of blinding diseases in China. The main complications are: 1. Posterior scleral staphyloma: the incidence is 77.1%. It mainly manifests as posterior expansion of the posterior pole of the eye, degenerative atrophy of the optic nerve and the retina around the macula, and decreased corrected visual acuity. The higher the degree of myopia, the higher the incidence of posterior scleral staphyloma. 2. Retinal atrophy and degeneration, hemorrhage and fissure: Due to factors such as elongation of the eye axis and posterior scleral staphyloma, highly myopic patients are prone to retinal degeneration and fissure, causing hemorrhage and retinal detachment, leading to blindness. 3. Subretinal neovascularization: the incidence is 5%-40%. It is manifested as subretinal neovascularization in the posterior pole, causing hemorrhage and affecting visual acuity. Retinal detachment, cataract, glaucoma: Due to scleral dilatation and retinal degeneration, the chance of retinal detachment is 7-8 times higher in highly myopic patients than in non-highly myopic patients. High myopia also has a higher chance of cataract and glaucoma complications than normal people. Some of these complications need to be treated promptly, and others, such as retinal degeneration and fissures, require preventive laser treatment to prevent blindness. Therefore, patients with high myopia should visit the hospital frequently to check the fundus and intraocular pressure in order to make early detection and early treatment.