Background Congenital nystagmus is an involuntary, rhythmic, pendulum-like or pulsating oscillation of the eye that can be manifested in dominant, recessive, or dominant-implicit states. Dominant nystagmus: nystagmus is present whether one eye is covered or not, or both eyes are opened at the same time, and the amplitude and frequency of nystagmus are usually the same in both eyes. Occult nystagmus: nystagmus occurs when one eye is covered, while nystagmus is reduced or even indistinguishable with the naked eye when both eyes are open at the same time. The incidence of congenital nystagmus is about 0.005-0.286%, which is common in males. Dominant congenital nystagmus is rarely detected at birth, usually at 3 to 4 months of age. It tends to decrease with growth and development. The causes of nystagmus can be classified as sensory deficient or motor deficient. Clinical manifestations and consequences 1. Nystagmus or oscillation: involuntary continuous, relatively regular nystagmus or oscillation in both eyes or in one eye. 2. Vision loss and amblyopia: Patients with nystagmus are unable to gaze steadily at external objects, resulting in a decrease in the quality of vision in both eyes, especially in childhood, which adversely affects the normal development of vision and causes more severe amblyopia. 3, compensatory head position: About 80% of patients have compensatory head position, mainly manifested as left and right deflection of the face, only a few cases show the lower collar up or inward, the head left and right tilt. The purpose of compensatory head position is to obtain better vision than the front at a certain gaze angle, to make the gaze time as long as possible and to reduce visual fatigue, but this brings impact on their appearance and even causes asymmetry of facial development. 4, strabismus: strabismus is one of the common complications, about 20% of patients combined with strabismus. 5. No shifting sensation: Although the eyes of patients with congenital nystagmus are in constant motion, there is no shifting sensation (self-perception of surrounding objects moving in a certain direction). The nystagmus may decrease or even disappear with age. Early diagnosis Some cases of nystagmus are caused by abnormalities in the eyes, so early detection and diagnosis is especially important. When nystagmus is detected, it is important to go to the hospital to rule out organic eye diseases such as congenital cataract, congenital glaucoma, and treatable diseases such as pediatric hereditary fundus disease. To restore the clarity of visual pathways and promote visual development in infants and children during the critical period of visual development (before age 2). Early treatment Treatment Objectives of treatment: Early treatment of primary diseases, active treatment of amblyopia, and improvement of visual acuity; the objectives of surgical treatment of congenital nystagmus mainly include improving compensatory head position and/or improving binocular visual quality (reducing nystagmus amplitude). The improvement of visual quality for nystagmus patients mainly includes the improvement of binocular and monocular visual acuity and the expansion of the range of visual field of attention. 1.Etiological treatment: symptomatic treatment Congenital cataract, congenital glaucoma and fundus disease should be operated as early as possible. 2.Improve visual acuity: for congenital nystagmus, the focus is on improving visual acuity and preventing the primary lesions that lead to amblyopia Those with refractive error need to wear glasses to prevent the formation of severe amblyopia. 3. Non-surgical treatment: Negative spherical lens overcorrection can stimulate the regulatory collection and suppress the nystagmus when looking at distance to improve visual acuity; it can also be equipped with appropriate prisms to eliminate compensatory head position and improve visual acuity. 4. Surgical treatment: congenital nystagmus with motor defects can be operated on. The surgery for congenital nystagmus is a complex surgery, and different surgical methods should be designed according to different patients. The degree of nystagmus can be traced by nystagmography before and after surgery. Nystagmography is more accurate than visual observation and can detect weak nystagmus that cannot be detected with the naked eye and provide various parameters such as type, frequency, amplitude, rhythm, duration, and speed of nystagmus for computer analysis. In cases of combined strabismus, simultaneous or staged surgical correction is possible.