First, the naked eye vision should be checked, if the naked eye vision does not meet the minimum vision standard for the corresponding age group, for example, not less than 0.5 for children aged 3-5 years old, and not less than 0.7 for children aged 6 years old and above. second, the examination of the eyes, including the cornea, the lens, and the fundus of the eyes do not show any obvious abnormality, in this case, it is necessary to do a dilatation of the pupil optometry examination. children under the age of 10 years old need to dilate their pupils with the chronic pupil dilatant atropine cream, and between 10 years old and 18 years old need to dilate the pupils with rapid pupil dilatation tolphenamide. Between the ages of 10 and 18, the pupil dilation is performed with the fast dilating agent tropicamide. An amblyopic eye is diagnosed when the corrected visual acuity, i.e., the visual acuity with eyeglasses, is still not 0.8.