Comprehensive Guide To Special Senses Eyes And Ears Practice Test

The occipital lobe’s visual cortex is supplied mainly by the posterior cerebral artery, so damage in that territory disrupts cortical processing of the opposite visual field. This typically produces a contralateral homonymous visual field defect, often a homonymous hemianopia, and because the macula has extra blood supply from adjacent areas, macular vision is frequently spared in PCA strokes. In contrast, the middle cerebral artery supplies lateral cortical areas and the optic radiations that pass through them, which can cause different, more complex or pie-slice field losses if affected; the anterior cerebral artery focuses on medial frontal regions, and the basilar artery affects brainstem or cerebellar structures. Thus, occipital lobe visual field defects point to involvement of the posterior cerebral artery territory.