Saccades

Saccades are fast, in the clinical sense conjugated eye movements. Their pu rpose is to bring the fovea to the visual targets. Different types of sacca des can be distinguished. Thescientific discussion is mainly focussed on fo llowing questions: how does the brain do the necessary transformation of th e retinal coordinates into craniotopic coordinates and whether the saccadic eye movements are primarily conjugated or disconjugated. The growing knowl edge about the function of these structures allows topographic diagnosis to be applied to disorders of saccadic eye movements. In general, cortical di sorders are distinguished by a prolonged saccadic reaction time. Frontal co rtical lesions are specifically characterised by loss of suppression of unw anted saccades arid disruption of saccades to remembered targets; parietal cortical lesions by disruption in the calculation of preceding saccades. Ce rebellar lesions - posterior vermis and caudal fastigial nucleus - become m anifest as dysmetric, hypermetrics saccades. Lesions of the pontine brainst em manifest as ipsiversive saccade paresis and slowing.