Under normal circumstances, a four-year-old child should have a normal naked eye vision of 0.5-0.6. If a child is found to have vision that is not in the normal range after a vision test, if it is below 0.5, it is generally considered that there may be refractive error or amblyopia, such as myopia, hyperopia or astigmatism. In this case, the treatment method should be chosen according to the different conditions. Refractive error requires early prescription of glasses to improve vision, while amblyopia requires masking treatment and amblyopia training, and should be treated as early as possible; the earlier the treatment is given, the greater the chance of recovery. If a four-year-old child’s bare eye vision exceeds 0.6, it is generally considered to be a sign of excessive eye development, possibly due to the child’s usual bad eye habits, resulting in rapid eye development, indicating that the child is likely to develop myopia, so this situation should also be noted.