A large difference between the reading obtained after dilation and the reading obtained before dilation is due to the presence of accommodation spasms. Adjustment spasm, which occurs in children and adolescents, is caused by prolonged close eye use and persistent spasm of the ciliary muscle after excessive contraction, which can lead to pseudomyopia. Pseudomyopia can be ruled out by using medication to paralyze the spastic ciliary muscle and eliminate the accommodation spasm. If there is a large difference between the results before and after dilating the pupils, it means that there is ciliary muscle spasm as well as true myopia, which is mixed myopia. The degree of myopia that disappears after pupil dilation is pseudomyopia, and the degree that is retained is true myopia, which requires glasses and is based on the results obtained after pupil dilation. At the same time, we should pay attention to the scientific use of eyes and try to avoid visual fatigue.