In general, the main causes of congenital nystagmus include visual impairment due to congenital ophthalmoplegia, albinism, cataract, total color blindness, macular damage, etc. Because there is no ability to fixate on the target, the eyes are mostly horizontal type nystagmus, which is called oculogenic nystagmus. In contrast, acquired nystagmus is mainly caused by central nervous system or vestibular lesions, such as cerebellar disease and vestibular nucleus lesions, which are called central nystagmus. In the case of middle ear or inner ear diseases, horizontal or rotational nystagmus may occur due to irritative or inhibitory disorders of the vagus, which is called vagal nystagmus.