Nasal visual field loss with intracranial lesions of the optic nerve pathways.

Five patients developed nasal visual field defects as a result of involvement of the intracranial portion of the optic nerves. The cause in each patient, respectively, was as follows: (1) dolichoectatic carotid arteries, (2) optochiasmatic arachnoiditis, (3) meningioma of the olfactory groove, (4) pituitary apoplexy, and (5) pituitary chromophobe adenoma. The common factor in these cases was probably impaired circulation in the prechiasmal arterial anastomotic network. The nasal visual field loss present in these cases was characterized by a pattern similar to that seen in glaucoma but with impairment of visual acuity. The superior nasal visual field was usually normal and the lower temporal visual field often defective.