Traumatic chiasmal syndrome associated with midline basilar skull fractures.

We studied two young males who had visual field defects consistent with optic chiasmal injury after blunt frontal head trauma. One patient also had a unilateral optic neuropathy. Long-term follow-up disclosed complete bi-temporal hemianopsias in these patients. Both patients had midline basilar skull fractures that traversed the midclivus through the sella turcica floor, dorsum sellae, and sphenoid sinus. Magnetic resonance images did not identify intrachiasmal hemorrhage as the cause of the visual field defect. We believe this fracture pattern, in conjunction with the magnetic resonance image findings, suggests tearing of the optic chiasm on a microscopic, if not macroscopic, scale as the cause of the complete bitemporal hemianopsia.