Age is one of the most important factors in determining the distribution of refractive errors. Only a small percentage of infants are born with myopia, and a large proportion of these are associated with genetics and premature birth of the infant. Infants have only a very low prevalence of myopia, and even when they reach school age 6 years, few are still myopic. In the next 6 to 8 years, low to moderate myopia predominates, and for juvenile myopia, the age of onset is mostly 7 to 14 years, and myopia stops at the age of 14 to 15 years for females and 15 to 16 years for males. After that, except for adult myopia, the refractive state tends to be stable and the length of the eye does not change significantly.