According to the different causes of amblyopia can be divided into the following 1, strabismic amblyopia: patients have strabismus or had strabismus, accompanied by amblyopia, but no fundus abnormalities. 2, refractive parallax amblyopia: due to the large difference between the refractive error of both eyes, so that the macula of the two eyes formed by the image clarity is not equal, even if the refractive error is corrected, the refractive parallax caused by the size of the image is still not equal, resulting in the image of both eyes is not easy or can not be fused into one, the visual cortical center can only inhibit the refractive error of the larger eye image, so the development of amblyopia over time. 3, form deprivation amblyopia: in infancy, due to corneal clouding, congenital cataract, or ptosis obscuring the pupil and other organic lesions resulting in light stimulation can not fully enter the eye, depriving the macula of the opportunity to receive normal light stimulation, resulting in functional impairment of amblyopia. 4, congenital amblyopia: the pathogenesis is not yet clear. Foreign scholars speculate that newborns often have retinal or optic pathway hemorrhage, which may affect the normal development of visual function. Some congenital amblyopia is secondary to nystagmus. Refractive amblyopia: mostly bilateral, occurs in patients with high refractive error who have not worn corrective glasses. The visual acuity of both eyes is equal or similar. Refractive amblyopia is mostly seen in people with hyperopic refractive error.