There is also a saying that "since the invention of eye exercises in 1963, the incidence of myopia among teenagers in China is as high as 50%-60%, while in the United States where eye exercises are not carried out, the myopia rate is only 25%." This data can't show that eye exercises are harmful to vision. A large number of studies show that myopia is related to heredity. If both parents are nearsighted, the possibility of children's myopia is as high as 33-60%; If both parents are not nearsighted, the possibility of children being nearsighted is only 6 ~ 15%. Of course, this does not mean that myopia has nothing to do with the environment, because gene expression can not be separated from environmental factors, and some environmental factors (such as reading) may be the cause of myopia.