Isolated bitemporal hemianopsia due to traumatic chiasmal syndrome.

A 20-year-old man presented with complaints of inability to see the outer half of objects and blurred near vision while reading. His complaints began one year ago after a motor vehicle accident that caused cranio-orbital fractures. Ocular examination revealed complete bitemporal hemianopsia and slight exotropia. Central visual acuity was 20/20 in both eyes. Radiologic studies demonstrated fractures in the fronto-ethmoid and sphenoid bones and thinning of the optic chiasm. No hypothalamic-pituitary abnormality was detected. Clinical findings remained unchanged during follow-up. Although rare, blunt head trauma may cause an isolated damage to the chiasmal crossing nerve fibers, resulting in a complete, bitemporal hemianopsia associated with normal visual acuity. Traumatic chismal syndrome should be considered in the differential diagnosis of patients presenting with bitemporal hemianopsia.