It is the uncontrollable and involuntary movement of the eye. It could be horizontal, vertical, rotative, oblique or in any combination.

Nystagmus is associated to a malfunctioning of some portions of the brain wich are responsable for controling movements. Nevertheless, it is unknown the exact nature of this anomalies.

Patients with nystagmus often turn their heads in a not common position to increase their vision, trying to reduced the eye movements effect .