Congruous quadrantanopia and optic radiation lesion.

Homonymous visual field defects are rare in patients with MS and are usually caused by large lesions in the white matter of the posterior optic radiations and visual cortex. The postulate of Holmes and others, early this century, that optic radiation lesions could produce quadrantic defects has recently been questioned. We report the full recovery of a patient with probable MS who presented with congruous quadrantanopia from a small white matter lesion in the contralateral trigone area.