Walsh & Hoyt: Congenital Nystagmus

Congenital nystagmus is usually diagnosed during infancy, but occasionally presents during adult life when it may create a diagnostic problem, especially if the patient has other symptoms, such as headaches or dizziness. Certain clinical features usually differentiate congenital nystagmus from other ocular oscillations. It is almost always conjugate and horizontal, even on up or down gaze. A small torsional component to the nystagmus is probably common, but is difficult to dentify clinically. Only rarely is congenital nystagmus purely vertical. Congenital nystagmus is usually accentuated by the attempt to visually fixate an object and by attention or anxiety. Eyelid closure and convergence usually suppress it, but occasionally congenital nystagmus is evoked by viewing a near target. Its intensity may also be influenced by viewing the vertical lines of an optokinetic tape. Congenital nystagmus often decreases when the eyes are moved into a particular position in the orbit, called the ""null"" region. In some patients, the direction of the nystagmus spontaneously reverses direction during sustained viewing of a fixation point. The direction of the nystagmus may also be influenced by which eye is viewing, with the nystagmus beating away from the covered eye; this is similar to latent nystagmus.