The traditional diagnostic criteria for amblyopia are: no obvious organic lesions in the eye, visual impairment caused mainly by functional factors, and best corrected visual acuity below 0.8. Due to the different visual development of children of different ages, the new diagnostic criteria for amblyopia have supplemented and improved the old criteria, taking into account the developmental characteristics of children of different ages, and the new diagnostic criteria for amblyopia are: no obvious organic lesions in the eye, visual impairment caused mainly by functional factors, and best corrected visual acuity below normal for the age group. The best corrected visual acuity is lower than the normal visual acuity of the age group. Specifically, amblyopia is diagnosed if the best corrected visual acuity is less than 0.5 in children under 3 years old, less than 0.6 in children 4-5 years old, less than 0.7 in children 6-7 years old, or if the best corrected visual acuity of both eyes differs by more than two lines. Amblyopia occurs in childhood and seriously affects the child’s learning and life, and even threatens the child’s safety. Amblyopia occurs when the most sensitive part of the eye, the macula, is unable to receive sufficient visual stimulation due to eye abnormalities. The causes of amblyopia in children include the following five categories: strabismic amblyopia, refractive amblyopia, refractive error amblyopia, form deprivation amblyopia, and congenital amblyopia. Strabismic amblyopia is the most common, with a predilection for monocular constant strabismus. The number of children with amblyopia in China is estimated to be more than 10 million, which should attract our great attention. Parents should pay attention to their children’s vision condition and detect possible vision abnormalities early. Children with visual anomalies may have a tendency to see things close together, squint at TV, squint at objects, strabismus, nystagmus, etc. Severe binocular vision anomalies may be manifested as the phenomenon of “blindness”, i.e., not looking at the target and not turning the eyes with the movement of people or objects. Parents should have high suspicion of vision abnormalities once they find the above, and go to the hospital for early examination. For children with monocular amblyopia, if there are no obvious abnormalities in the outer eye, they are not easily detected by parents. Therefore, vision examinations after the age of 3 when the child can cooperate with the examination can detect vision abnormalities early and provide early treatment. There are many treatment methods for amblyopia, and the effect of treatment is closely related to the age of the child, the degree and type of amblyopia, and the younger the age of starting treatment, the better the effect. Amblyopia should be treated before the age of 8, that is, before the development of visual function is complete, if the treatment is done after the age of 8, the effect will be deviated, and the effect will be worse if it is over 12 years old, so once amblyopia is detected, it should be treated early. There are many ways to treat amblyopia, including: masking, posterior image therapy, visual stimulation therapy, red consideration light tablet therapy, suppression therapy and drug therapy developed in recent years. Training methods include amblyopia therapy devices, computer software (CD-ROM or internet), etc. Different methods include basic training methods. For monocular amblyopia or those with a large difference in binocular vision, traditional masking therapy is very important. The specific methods of masking are: 1. Correct optometry and prescription; 2. Covering the healthy eye or the one with better vision. Masking can be divided into complete masking (full-day masking) and partial masking (daily masking for a few hours), and the masking is best complete and thorough so that the child cannot peek, and the eye patch is best covered over the eye. The effect of masking is not as good as masking on the eyes, and the mask can also be homemade, with black cloth as the outer layer and red cloth as the inner layer; 3. To train the amblyopic eye, amblyopia therapy devices, CD-ROMs or internet training can be used, together with vivid and interesting fine visual work such as threading needles, wearing small beads or drawing pictures, to ensure that the macula of the amblyopic eye has sufficient visual stimulation, so as to improve visual acuity. In addition to checking the visual acuity of the amblyopic eye, we should also pay attention to the visual acuity of the healthy eye to prevent amblyopia from occurring in the healthy eye, especially in younger children. The improvement of vision in the amblyopic eye of the child is a slow process, and the masking and vision training requires patient persistence of the child and patient supervision of the parents, as well as regular follow-up visits, usually once every six months. Amblyopia seriously affects the healthy growth of the child and should be highly valued by parents, who should care about their children’s visual health, discover the existence of visual abnormalities early and treat them as soon as possible in order to restore a bright and clear pair of eyes to the child.