The best corrected visual acuity of one or both eyes caused by monocular strabismus, uncorrected refractive error, high refractive error and form deprivation during visual development is amblyopia; or the visual acuity of both eyes differs by more than 2 lines, and the visual acuity of the lower eye is amblyopia. 1, the clinical work should avoid two kinds of error tendency: 1, when diagnosing children’s amblyopia, must first carry out a systematic examination to exclude ocular organic changes; at the same time should find the relevant factors leading to amblyopia, not only based on visual acuity 1 index that is diagnosed amblyopia. 2. According to the law of children’s visual development, for children aged 3-7 years, the diagnosis of amblyopia should not be based on visual acuity lower than 0.9, but should refer to the lower limit of the normal value of visual acuity for the corresponding age. The lower limit of normal value of visual acuity for children of different ages The lower limit of normal value of visual acuity for children aged 3 to 5 years is 0.5, and the lower limit of normal value of visual acuity for children aged 6 years and above is 0.7. Classification of amblyopia 1. Strabismic amblyopia: amblyopia formed by monocular strabismus. 2. Refractive amblyopia: amblyopia formed in the eye with higher refractive error when the difference in refractive error between binocular hyperopic spherical lenses is 1.50DS or column lenses is 1.00DC. Refractive error amblyopia: mostly occurs in patients with high refractive error who are not wearing refractive error correction glasses. The refractive error is mainly high hyperopia or astigmatism in both eyes, and the best corrected visual acuity in both eyes is equal or close. Hyperopic refraction ≥5.00DS and astigmatism ≥2.00DC can increase the risk of amblyopia, which is usually diagnosed after 3-6 months of wearing refractive error correction glasses. 4, form deprivation amblyopia: due to refractive interstitial clouding, ptosis and other form deprivation factors caused by amblyopia, can be monocular or binocular, monocular form deprivation amblyopia is more serious than binocular amblyopia consequences. Different visual acuity tables should be used for children of different ages. For children younger than 3 years old, the visual acuity can be checked by selective viewing (PL), nystagmus (OKN), visual evoked potential (VEP), or using the children’s visual acuity chart; for children aged 3 years and above, the international standard visual acuity chart currently used in China can be used to check visual acuity. Qualitative examination of the difference in visual acuity between the two eyes of children should be emphasized clinically, and poorer gaze function and lower visual acuity in the eye can be diagnosed as amblyopia after excluding organic pathology.