Myopia prevention and control is done in two main ways. One, myopia prevention, that is, reducing the risk of myopia onset. Second, it is the control to control the progression of the degree of children who have developed myopia. The main reason why myopia prevention and control is necessary is that the incidence of myopia in China is very high, especially among adolescents, and once myopia occurs in adolescents, the degree of myopia is often unstable and is likely to grow especially fast. This can even lead to retinal detachment. If high myopia is prolonged, it can easily cause retinal atrophy or neovascularization, resulting in a persistent and irreversible loss of vision. Children who are not yet myopic need to delay the onset of myopia as early as possible to reduce the likelihood of high myopia. The risk of myopia in low myopia is generally not great, and the risk of myopia in high myopia can be great, so prevention and control of myopia is very necessary.