Amblyopia is a condition in which vision is low in one or both eyes and corrective lenses do not improve vision, but vision can be partially or fully restored with masking therapy at an early age. Amblyopia is a condition associated with both eyes and is the result of an imbalance in the input of visual stimuli to both eyes early in visual development, with the dominant being the dominant eye and the inferior becoming the inferior eye, or low vision in one or both eyes caused by visual deprivation. Amblyopia is divided into five major categories, namely strabismus, refractive error, refractive error, form deprivation and congenital amblyopia. 1, strabismic amblyopia: after the occurrence of strabismus, the visual axis of both eyes is not parallel, and the object image of the same object falls on the non-corresponding point of the retina of both eyes, thus causing diplopia. Another object image, which is completely different from the macula of the strabismic eye, will fall on the macula of the strabismic eye, and these two clear and different object images cannot be fused, thus causing visual confusion. The double vision and visual confusion caused by strabismus, especially the latter, make the patient feel extremely uncomfortable, so the visual cortex actively inhibits the visual impulse input from the macula of the strabismic eye, and the macular function of the eye is inhibited for a long time, thus forming amblyopia. 2. Refractive parallax amblyopia: The refractive inequality of both eyes is called refractive parallax. Because the refractive aberration is too large, the clarity of the object image on the macula of both eyes is not equal. Even if the refractive aberration is corrected, the size of the resulting image is still unequal, making it difficult or impossible for the two eyes to fuse into one, and the visual cortex has to suppress the image from the eye with the larger refractive error. Unilateral high hyperopia is particularly common in children with unilateral high myopia. In hyperopic refractive error cases, the shallow hyperopic eye can obtain a clearer image, while the same object cannot be further adjusted by the deeper hyperopic eye, so the image is blurred and amblyopia develops over time. However, patients with high myopia often use one eye with deeper myopia to see near and one eye with shallower myopia to see far, so that both eyes can get clear images, which can not cause amblyopia. Unilateral astigmatism can also produce amblyopia. 3, refractive amblyopia: mostly occurs in highly refractive cases that have not worn corrective glasses, especially in highly hyperopic. Due to the limitation of adjustment, patients can see near and far are blurred, can not get a clear image and form amblyopia. Highly myopic patients can’t see far, but can get a clear image near, so they don’t have amblyopia. Refractive amblyopia is mostly bilateral, with similar or equal visual acuity in both eyes and no binocular fusion disorder, so it does not cause central brain inhibition and has a good prognosis, and after wearing suitable corrective glasses, visual acuity can be improved, but it takes longer. If the visual stimulation therapy can be carried out, the course of treatment can be greatly shortened. 4, form deprivation amblyopia: deprivation amblyopia can be caused by congenital cataract, corneal clouding, ptosis, etc., which cover the affected eye for a long time during infancy or by covering the healthy eye for amblyopia treatment. This is due to insufficient light entering the eye, depriving the macula of the opportunity to form a clear image and resulting in amblyopia. The prognosis for this type is more severe than for other clinical types. Morphological deprivation amblyopia can be unilateral or bilateral, with unilateral cases being more severe. Pseudo-deprivation amblyopia can also occur in infancy and early childhood, even if the eye is briefly masked unilaterally. These types of amblyopia differ in terms of their pathogenesis. In strabismic, refractive amblyopia and refractive error amblyopia, the macula of both eyes is involved in the visual development process to some extent, and the light stimuli entering both eyes are equivalent, forming images in the macula and peripheral retina, so the prognosis is better and all three types of amblyopia are reversible with appropriate treatment at an early age (during the plastic phase of visual development). On the contrary, in deprivation amblyopia, monocular or binocular in infants and children whose vision has not yet developed to a perfect or mature stage, the retina does not receive enough light stimulation to participate in the visual development process, so the prognosis is poor. Diagnosis: Refractive examination: examination under atropine ciliary muscle paralysis. ingram’s study noted that amblyopia and internal strabismus are likely to occur if the refractive error is shallow in one eye with +2.00 to +2.75 spherical lenses. The greater the refractive error, the greater the likelihood of amblyopia, and the greater the degree of amblyopia. The incidence of amblyopia is significantly higher in patients without internal strabismus who have a spherical lens difference of 1.00 to 1.75 or a column lens difference >1.00 in both eyes. Amblyopia is likely to occur in patients with internal strabismus who also have refractive aberrations. Treatment of amblyopia The key to amblyopia treatment is accurate optometry, children also need to dilate the pupil for optometry, wear appropriate glasses, on this basis for treatment, the methods mainly include the following: (1) traditional masking method + fine visual homework: cover the eye with good vision, force the amblyopic eye (eye with poor vision) to see, while doing fine visual homework. This method is simple and easy to implement and is suitable for strabismic amblyopia and refractive amblyopia with reliable results. (2) Amblyopia therapy instrument treatment. (3) Visual stimulation therapy (i.e. CAM stimulator): the use of contrasting bars with different spatial frequencies as a stimulation source to stimulate the amblyopic eye to improve visual acuity. This method is simple and easy to implement, each treatment time is short, the effect is fast, especially for refractive amblyopia. （For amblyopia caused by strabismus, congenital cataracts and ptosis, surgery should be actively used to treat these eye diseases, and the child needs to be examined in time after surgery to determine whether to wear glasses. In particular, after congenital cataract surgery, glasses are needed to solve the adjustment problem of seeing far and near, and glasses are worn for life. Amblyopic children with combined strabismus should be treated first for amblyopia and then for strabismus. For those with congenital strabismus is surgery to correct the strabismus first, followed by amblyopia training. For amblyopia with combined high number strabismus, amblyopia is treated first for a period of time, and then the strabismus is surgically corrected after the visual acuity is partially improved and the eye position is corrected before continuing to treat the amblyopia. Amblyopia treatment takes a long time and requires the active cooperation of the child and parents, otherwise not only half the effort is needed, but also half the effort may be lost. Parents’ concern and active cooperation are related to the success or failure of amblyopia treatment.