Children’s eyes are in the stage of growth and development, and the anatomy and physiology of the visual system and the types of eye diseases in children, pathogenesis, timing of treatment, and purpose of treatment are many different from those of adults. During the sensitive period of visual development (especially before the age of 3 years), any factors that affect visual development can affect the development and establishment of visual acuity and binocular vision. The effectiveness of treatment for many childhood eye diseases is closely related to the age of treatment; the younger the age, the better the outcome and the higher the cure rate; some diseases cannot be cured if treatment is missed. That is why early detection of vision problems is the key to treatment. So how to detect abnormal vision in children at an early stage? First of all, parents should observe their children carefully, which can be judged by the following aspects: 1. Young children’s eyes cannot catch the light, or cannot gaze at the object of interest. 2. The child does not respond when one eye is covered, and cries when the other eye is covered. 3.Squints, tilts head, frowns or likes to move towards the TV. 4.Looking at writing work too close, incorrect posture or preferring to close one eye in the sunlight, etc. 5.Various kinds of strabismus, eye swaying, eyelid drooping, white pupil area, etc. All of these may be signs of low vision and possible eye disorders, which must be checked early at the hospital. Early vision examinations are very important for the early detection of vision problems. Vision examinations are extremely important for the correct diagnosis and prognosis of various childhood eye diseases, especially in the screening of amblyopia in children and the prevention and treatment of myopia in adolescents. In general, most children over the age of 3 can cooperate with vision examinations after training, so children over the age of 3 should have their vision checked at least twice a year in order to detect problems and treat them in a timely manner.