When testing the eyesight of children aged 3-6 years old, the distance of the test is determined by the design of the vision chart. Some are designed for 2.5m, some for 3m, and some for 5m. It is recommended to use a 5m meter for accuracy, because 5m produces an adjustment of 0.2D, while 2.5m produces an adjustment of 0.4D. A child with 50 degrees of nearsightedness will tend to have normal vision when looking at a 2.5m meter, while 25 degrees of nearsightedness will tend to have normal vision when looking at a 5m meter. When looking at a 5 meter meter, 25 degrees of myopia will only tend to normalize when looking at the visual acuity meter. The use of a 2.5m meter may increase the error rate of the test and result in a high visual acuity. Therefore, a 5m meter is recommended for children’s eyesight testing, which is relatively more accurate.