Strabismic amblyopia : is monocular amblyopia. It occurs in monocular strabismus, and binocular alternating strabismus does not form strabismic amblyopia. Due to the abnormal binocular interaction caused by the strabismus, the different objects received by the macular sulcus of the strabismic eye (confusion) are suppressed, resulting in a decrease in the best corrected visual acuity of the strabismic eye. Refractive parallax: Refractive parallax between two eyes (1.5DS for hyperopic spherical lens and 1.0DC for column lens) can cause amblyopia to form in the higher refractive eye. Refractive parallax amblyopia is caused by two factors: abnormal interaction between the two eyes and form deprivation. Refractive amblyopia: This is a binocular amblyopia that occurs in patients with high refractive error who have not worn refractive correction glasses. It is mainly seen in patients with high hyperopia or astigmatism in both eyes, and the best corrected visual acuity is equal or similar in both eyes. It is generally accepted that hyperopia ≥ 5 DS, astigmatism ≥ 2.0 DS, and myopia ≥ 10.0 DS increase the risk of amblyopia. Lineal deprivation amblyopia: Amblyopia is more likely to develop during the critical visual period due to refractive interstitial clouding (corneal leukoplakia or cataract), complete ptosis, resulting in decreased visual acuity in that eye, and monocular form deprivation.