Myopia, is one of the most common eye diseases worldwide. The prevalence in China is also high, and myopia has become one of the important elements for parents to pay attention to their children’s healthy growth. Myopia is a condition in which the eye is adjusted so that parallel light rays pass through the refractive system of the eye and form a focal point in front of the retina, so that seeing far is blurred. In general, the front and back eye axes of myopic eyes of teenagers are longer than those of normal teenagers, so the focus of light falls in front of the retina, and a concave lens needs to be worn in front of the eye to disperse the light so that the focus falls exactly on the retina, i.e. a clear image is formed. 1, analysis of the causes of myopia, no more than the following: (1) genetic factors: mostly seen in patients with high myopia. (2) Developmental factors: When a normal child is an infant, the eye is small and physiologically farsighted. As the eye grows older, the tissues of the eye increase accordingly and some children’s retina overdevelops and the eye axis elongates, which forms myopia. (3) Adjustment factors: Nowadays, primary and secondary school students have a lot of homework, and their eyes are close to books for a long time, which makes the ciliary muscle overly tense, the lens becomes convex, and the distant point moves closer, so the distant object becomes a blurred image. In the long run, this leads to true myopia. This is the main factor in the formation of most myopia today. Therefore, usually should pay attention to eye hygiene, reading, writing, eyes and books should be kept at a certain distance, lighting brightness should be selected incandescent, can reduce the flicker and reflection of fluorescent lamps. When reading close to an hour, you should rest for a few minutes or look into the distance to relax the ciliary muscle. The incidence of myopia has increased rapidly in the past 20 years or so. Genetics and excessive eye development are some of the factors, but the most important reason is the continuous long-time close eye use. According to the survey statistics, children who eat more sweets have a greater increase in myopia than those who eat less or no sweets. Therefore, it is recommended that young children eat less sweets, especially chocolate, candy, ice cream, etc. 2, to distinguish between true or pseudomyopia: suffering from myopia, do not blindly go to the optician’s computerized optometry after prescription lenses, it must be noted that students under 12 years of age, the application of 5% tropicamide eye drops to dilate the pupil, such as ciliary muscle relaxation after the optometry, in order to exclude the possibility of pseudomyopia, to avoid unnecessary prescription lenses. (1) Pseudomyopia is caused by excessive use of the eye at close range, and the ciliary muscles in the eye are adjusted by contraction to move the focal point closer, and over time, the phenomenon of transient myopia is manifested. (2) In true myopia, the eye axis is elongated due to genetics or excessive development, and myopia does not change after using pupil dilation medication. In the case of pseudomyopia, glasses are not needed and the symptoms will be reduced after the eyes rest and relax. True myopia requires glasses. The principle of prescription: choose the lens with the lowest prescription that allows the patient to obtain the best visual acuity. Here, students are advised; they should pay attention to nutrition, increase carotene and calcium appropriately, and eat less sweets to make the eye axis less likely to elongate and reduce the degree of myopia development each year. And follow up regularly on the degree of vision and myopia to adjust the appropriate glasses lenses in time.