Background: A lesion affecting the optic radiations may produce a quadrantanopia based on the topographical arrangement of the geniculocalcarine tract. Objective: To determine the localizing associations of a quadrantic visual field defect. Design: Retrospective study of case records of 41 patients with inferior quadrantanopia and 30 patients with superior quadrantanopia caused by disorders affecting the posterior visual pathway. The responsible lesion was identified with neuroimaging techniques. Setting: Neuro-ophthalmology referral practice in a large multispecialty clinic that: provides primary, secondary, and tertiary medical care. Results: Cerebrovascular disorders accounted for most lesions. The location (and frequency) of lesions causing inferior quadrantanopia was occipital lobe (76%), parietal lobe (22%), and temporal lobe (2%). Other localizing signs were associated with 6%, 89%, and 0% of lesions located in the occipital, parietal, and temporal lobes, respectively. The location (and frequency) of lesions causing superior quadrantanopias was occipital lobe (83%), parietal lobe (3%), and temporal lobe (13%). Other localizing signs were associated with 4%, 100%, and 0% of lesions located in the occipital, parietal, and temporal lobes, respectively. Conclusions: A patient with a neurologically isolated quadrantanopia is likely to have a lesion in the occipital lobe, although, in the case of a superior quadrantanopia, the possibility of a temporal lobe lesion can not be excluded using clinical criteria only. Quadrantanopias caused by lesions of the parietal lobe usually are associated with other localizing signs.
