Impairment of visually evoked eye movements with a unilateral parieto-occipital lesion.

A 65-year-old woman had reduced and slowed visually guided saccades contralateral to a parieto-occipital tumour, contrasting with normal voluntary saccades. Ipsilateral pursuit movements were also impaired. These findings suggest that the parieto-occipital region may be critical for generating all visually evoked eye movements. The full-field pursuit was more impaired than the foveal pursuit; this unusual dissociation may occur when the lesion involves more the interhemispheric than the intrahemispheric occipito-parietal connecting fibres.