Congenital or infantile nystagmus is a clinical sign that may take many different forms. Involuntary, rhythmic eye movements are characteristic, as they are in acquired nystagmus. Waveform, amplitude, and frequency can vary with changes in focal distance, direction of gaze, and under monocular or binocular viewing conditions.
Oscillations are usually horizontal in direction but may be primarily vertical, torsional, or any combination of these three. Infantile nystagmus often is associated with other ocular conditions that impair visual acuity and occasionally can herald life-threatening conditions. Prompt assessment by an ophthalmologist with knowledge of infantile nystagmus to establish the need for and urgency of additional evaluation is extremely important.