According to the latest diagnostic criteria for amblyopia developed by the Strabismus Group of the Chinese Medical Association’s Ophthalmology Branch in 2010, amblyopia is defined as an abnormal visual experience caused by the presence of strabismus, uncorrected refractive error and high refractive error, as well as form deprivation and other abnormal visual experiences, with best corrected visual acuity in one or both eyes below the lower limit of visual acuity for the corresponding age, or with a difference in visual acuity of more than 2 lines between the eyes, occurring during visual development. The best corrected visual acuity for each age group is below the lower limit of visual acuity for the respective age group. The lower limits of best corrected visual acuity for each age are 0.5 for children under 3 years old, 0.6 for children between 4 and 5 years old, and 0.7 for children between 6 and 7 years old.