gms | German Medical Science

Vascular strokes of occipital cortex are mostly of ischemic origin. Vascular occlusions involve the calcarine artery or a more proximal part of the posterior cerebral artery. Anatomic variations explain cortical lesions after occlusion of the parieto-occipital branch of middle cerebral artery, branch of internal carotid artery. In 20% of cases, cortical lesions are consequences of intracerebral or subarachnoid hemorrhage.

Vascular strokes of occipital cortex result in complete or incomplete homonymous hemianopsia, invariably congruous and usually associated with macular sparing and preservation of temporal crescent. These characteristics are related to the retinotopic organization of the visual pathways. Lesions are uni or bilateral. Visual field defects are preferentially explored with cinetic campimetry allowing a complete analysis.Automatized perimetry is useful only to study the macular sparing in the central visual field. Defects may be misleading when associated with pathologies such glaucoma, high myopia and age related maculopathy. Improvement of the visual field defect is incomplete, occurring when defects have sloping margins, mostly in hemorrhagic lesions. Unilateral homonymous homianopia induce a variable handicap, well compensated by developpement of oculomotur and cephalomotor strategies.