A decrease in visual acuity, typically in one eye, resulting from abnormal visual experience during early childhood. It is caused by factors that interfere with normal binocular vision development, such as strabismus, anisometropia, or visual deprivation (e.g., congenital cataract). The affected eye appears normal, but the brain favors the other eye, leading to reduced visual acuity. Early detection and treatment are crucial for the best visual outcomes.