Nystagmus 1, Congenital, X-linked

Congenital nystagmus is a feature of numerous ocular and systemic disorders.  Isolated idiopathic congenital nystagmus (CN), however, refers to a diverse group of abnormal eye movements which are identified usually in the first 6 months of life when no other ocular abnormalities are present.  Horizontal eye movements are typical, but vertical and rotary eye movements have also been reported.  If the nystagmus is horizontal, the eye movement is usually "to-and-fro".   In general, as the patient gets older, the amplitude of the nystagmus decreases and the frequency of the nystagmus increases, particularly when the patient tries to fixate or look directly at an object. This nystagmus can increase in size and frequency when the patient is tired, sick, or fatigued.  Some very young patients are noted to have head nodding or head shaking, but these usually disappear over time. Vision is reduced and varies through the day. Balance may also be affected.  Many patients have a "null point" where the eye movement is reduced and vision is improved.  They may alter their head position in an effort to maximize their acuity.

Strabismus and amblyopia often develop.