Amblyopia is the result of insufficient effective stimulation of visual cells during visual development due to abnormal visual experiences (monocular strabismus, refractive error, high refractive error and form deprivation), resulting in lower best corrected visual acuity in one or both eyes than in normal children of the same age, with no organic pathology on general ophthalmic examination. Some patients can be cured with timely and appropriate treatment. The current prevalence of amblyopia in the population is 2-4%. Children’s vision and binocular vision have a gradual process of formation, refinement, and consolidation, which is a process of visual function development, accompanied by some degree of structural refinement. After birth, as with other systems and organs of the body, the visual system is not fully functional and there is a functional developmental stage between incompetence and soundness. This developmental process requires a normal eye structure as a foundation, appropriate visual stimulation, and the proper functioning of the visual system to obtain adequate training. The critical period of visual development in children is from 0 to 3 years old, the sensitive period is from 0 to 12 years old, and binocular visual development matures from 6 to 8 years old. The visual acuity of children at different stages of development varies. What should be the normal visual acuity of a child? In order to determine whether a child’s vision is developing normally, it is important to know the normal range of visual acuity at different ages. According to the published literature on the use of different methods (OKN, VEP, PL) to determine the visual acuity of mammary children, most experts believe that the visual acuity of normal newborns and children in the first month of life is photopic to immediate manual, 2 months is immediate manual to 0.01, 3 months is 0.01 to 0.02, 4 months is 0.02 to 0.05, 6 months is 0.06 to 0.08, and 8 months is 0.06 to 0.08. 0.08, 0.1 at 8 months, 0.2 to 0.3 at 1 year, 0.5 to 0.6 at 2 years, and may reach about 1.0 at 3 years. However, there are also studies that point out that there are differences in visual development, some earlier, some later, but most scholars believe that normal adult vision does not develop until after 6 years of age (or even 10 years). Because it is impossible to know the exact visual acuity of a child, especially before the age of 3 years, it is more important to examine qualitatively than quantitatively, and it is more convenient and valuable to determine whether there are differences in the visual acuity of the two eyes than to know the visual acuity of each eye. Children after the age of 3 years are more likely to be able to cooperate with visual acuity examinations, and the lower limit of normal visual acuity is 0.5 for children aged 3 to 5 years, and 0.7 for children aged 6 years and older. The difference in visual acuity between the two eyes on the Snellen visual acuity chart should not exceed two lines. The visual function of young children is not yet mature by the age of 6, and the visual function is not yet sound and consolidated, which is a plastic and changeable stage. Amblyopia is a treatable visual deficiency disease. Amblyopia can be detected through eye screenings in early childhood and can be cured if detected early and treated promptly. Therefore, early detection of eye diseases affecting children’s visual development through eye health education, vision assessment and screening of related eye diseases, and early correction can protect and promote the normal development of children’s visual function.