Background: Previous reports have suggested that most cases of homonymous hemianopia (HH) are caused by occipital stroke. However, these reports have not always been supported by brain imaging.
Methods: We reviewed the medical records of all patients seen in our unit between 1989 and 2004 who had HH documented by formal perimetry or confrontation visual fields and had undergone brain imaging. HHs were divided into those caused by stroke and by non-stroke conditions. The clinical and visual field characteristics were compared in the two groups.
Results: Among 850 patients with 902 HHs, 629 (69.7%) resulted from stroke, of which 531 (84.4%) were from infarction and 98 (15.6%) from primary intraparenchymal hemorrhage. Non-stroke causes included head trauma (123), brain tumor (102), neurosurgical procedures (22), multiple sclerosis (13), and miscellaneous conditions (13). Occipital lesions most commonly resulted from stroke. The configuration of the HH did not predict where in the retrochiasmal visual pathway the responsible lesion lay.
Conclusions: Ischemic stroke causes most HHs from lesions in the occipital lobe that generally do not produce other neurologic manifestations. The configuration of the HH does not predict the location of the lesion within the retrochiasmal visual pathway.