Children over the age of three, with parental training, can basically read the E-type vision chart, which is the same as the vision chart used for adult examinations. As long as the level of cooperation is good, the test results are relatively accurate. It is important to note that a child’s vision does not develop to normal, like an adult’s, until the age of 8-9, which is 1.0 or 1.2. Until the age of 8-9, vision is a gradual growth process and cannot be considered abnormal if it is lower than 1.0, which is determined in conjunction with age. The lower limit of visual acuity is 0.5 for three-year-olds, 0.6 for four-year-olds, 0.7 for five-year-olds, and 0.8 for seven-year-olds and above. only if the results of the visual acuity tests for each age group are lower than the lower limit of visual acuity required by the age group can we determine that there is a problem with visual development. At this time, further examination at the hospital is needed to clarify the cause and whether the loss of vision is due to myopia, hyperopia or amblyopia, or other eye diseases.