Vergence deficits in cerebellar lesions

The cerebellum is part of the cortico-ponto-cerebellar circuit for conjugate eye movements. Accordingly, cerebellar lesions cause smooth pursuit deficits and saccadic dysmetria. In contrast, the role of the cerebellum for disconjugate, i.e. vergence eye movements in humans is still unknown. The aim of this study was to investigate whether cerebellar lesions affect vergence eye movements. Similar to conjugate eye movements, vergence can be separated into two different components: vergence to step targets (fast vergence) and vergence to ramp and sinusoidal targets (slow vergence). Eye movements (fast and slow verg…