Criteria for risk factors in amblyopia screening developed by the American Academy of Pediatric Ophthalmology and Strabismus: 1. Refractive aberration (spherical or columnar) greater than 1,5D; 2. Any dominant strabismus; 3. Any meridional hyperopia greater than 3,5D; 4. Any meridional myopia greater than 3,0D; 5. Media clouding greater than 1mm; 6. Astigmatism greater than 1,5D in the 90° or 180° direction and oblique axial astigmatism greater than 1,0D; 7. 0D; 7, ptosis; 8, children aged 3-5 years with visual acuity less than 0,2 and difference in visual acuity between the two eyes greater than 2 lines, and children aged 6 years with visual acuity less than 0,67 and difference in visual acuity between the two eyes greater than 2 lines. The best time for screening: infants and toddlers have extremely unstable visual development before the age of 1 year, and basically stable after the age of 1 year, so this age is the most ideal time for screening.