Bilateral strokes are rare and should be considered when patients present with bilateral visual field loss characterized by patterns consistent with right and left-sided homonymous visual field defects. Perimetry, dilated funduscopy, and immediate neuroimaging are mandatory for diagnosis, because patients may present with vague symptoms. These cases reflect the retinotopic features of the striate cortex.
The purposes of this study were to describe the unusual presentation of bilateral homonymous visual field defects in three patients with bilateral ischemic strokes and to discuss the clinical and neuroanatomical correlations.
Neuro-ophthalmological examination including perimetry and brain magnetic resonance imaging (MRI) was performed in three patients with bilateral homonymous scotomas. Two of three patients presented with superior altitudinal hemianopia, resulting from right and left homonymous superior quadrantanopia due to bilateral occipital strokes below the calcarine fissure. A 57-year-old man (patient 1) with a history of atrial fibrillation presented with driving difficulties. Perimetry revealed bilateral superior altitudinal hemianopia. Brain MRI demonstrated a subacute right occipital stroke and a chronic left occipital stroke, both inferior to the calcarine fissure. An 83-year-old woman (patient 2) presented with reading disorders. Perimetry showed a left incomplete homonymous hemianopia and a right horizontal wedge-shaped homonymous scotoma. Brain MRI showed a chronic ischemic stroke in the left occipital lobe and acute ischemia in the right thalamus. A 40-year-old man (patient 3) was referred with headache, disorientation, and bilateral blurry vision. Perimetry showed bilateral superior altitudinal hemianopia, and MRI demonstrated acute bilateral occipital ischemia. Patients 1 and 2 suffered sequential bilateral strokes and were not aware of the initial scotoma, whereas patient 3 presented with bilateral concurrent strokes.
Bilateral homonymous visual field defects due to bilateral strokes are rare. Patient history, a careful neuro-ophthalmological examination, and correlation of visual field defect patterns with neuroimaging should prompt the clinician to the presence of this unique entity.