Positional vertical opsoclonus: A transient phenomenon in normal healthy twins

Opsoclonus is characterized by rapid bursts of involuntary, multidirectional, saccades without an intersaccadic interval. Three types of opsoclonus that occur in infancy have been identified, 2 of which are associated with a systemic or neurologic condition. The third is a benign condition that occurs transiently in healthy neonates and preterm babies. We report a case of 2 healthy twins who presented with transient opsoclonus, which was confined only to the vertical plane and manifested only in a supine position. Opsoclonus disappeared when the cheek was tapped. These eye movements began at 3 months and completely resolved by 6 months of age.