⑴ Young children may not have any symptoms, older children may complain of blurred vision, and parents may find some abnormalities in visual behavior, such as squinting, head deflection, and like to put the object in front of them when looking at near objects.

⑵ Patients may have congenital cataract, corneal scar, congenital blepharoptosis, etc.

⑶ Vision is low and cannot be corrected. Since most patients with amblyopia are children, it is very important to choose appropriate visual acuity evaluation methods.

(4) Light perception changes. Placing a medium density filter in front of amblyopia does not reduce vision, while the presence of organic lesions will reduce vision. In dim and weak light, the vision of amblyopic eyes changes little.

(5) Congestion occurs. The recognition ability of a single font is much higher than that of fonts of the same size but arranged in rows.

(6) Stereoscopic vision declines or disappears.

(7) The adjustment amplitude of amblyopia decreases.

(8) Accompanied by exotropia, nystagmus, etc.

(9) The contrast sensitivity (CS) function of amblyopia decreases at medium and high spatial frequencies, accompanied by the left shift of the peak.

(10) There are two kinds of gaze properties in amblyopia, namely, central gaze and eccentric gaze. Gaze at a point outside the fovea is eccentric gaze, which is divided into paracentric gaze, paramacular gaze and peripheral gaze.

(11) Amblyopia children show the decrease of visual cortex evoked potential (VEP) amplitude and the extension of peak time. This change of amblyopia is more obvious at medium and high frequencies.