Refractive errors mainly include myopia, hyperopia and astigmatism. The human eye is like a modern camera. This function is determined by its physiological characteristics. The eye has both refractive and regulatory functions. When parallel light is refracted by the refractive system (cornea, atrium, lens, vitreous humor) without adjustment, the focal point falls exactly on the retina, which means the eye is orthoopic. If the focal point falls in front of the retina, the eye is myopic. If it falls behind the retina, the eye is farsighted. The occurrence of refractive error is related to both genetic and environmental factors. A large number of population surveys and twin studies have shown that refractive error is an eye disease that is closely related to genetics. What are the manifestations and hazards of refractive error? 1. Loss of vision is the main symptom of refractive error. Nearsightedness, farsightedness and astigmatism have a direct impact on vision in different degrees. 2, visual fatigue is another common discomfort of refractive error. It is mostly related to the imbalance of the adjustment set. 3, refractive error long-term uncorrected will also cause strabismus amblyopia. Myopia and hyperopia have the tendency to form exotropia and endotropia respectively. 4. In addition, high myopia can cause fundus changes. In addition to the tendency to form internal strabismus and amblyopia, hyperopia also causes glaucoma, etc. Age distribution of refractive errors Statistics show that low vision before the third grade is often caused by hyperopia, astigmatism, and congenital myopia. The proportion of myopia increases after the fourth grade, and low vision among high school students is often caused mainly by myopia. Most of the children and adolescents with vision loss first occur at the age of 10-15, and more than half of them are concentrated at the age of 12-15. However, in recent years, with the improvement of people’s living conditions and the popularity of TV and computers, the age of myopia onset has tended to be earlier. Simple myopia tends to stabilize around the age of 20. Refractive error prevention There is no way to completely avoid the occurrence of refractive error. For myopia, prevention is the main focus, and efforts can be made to reduce the onset of myopia or slow down the progression of myopia by reducing close working hours, paying attention to eye hygiene, and improving the visual environment. For children and adolescents with true myopia, hyperopia and astigmatism, the main treatment at this stage is mainly glasses. The aim is to improve the corrected visual acuity and treat amblyopia and partial strabismus by wearing suitable glasses.