[Case of traumatic chiasmal syndrome]

Traumatic neuropathy of the optic chiasm is a rare finding which occurs after severe blunt head trauma. It is often accompanied by dysfunction of the pituitary gland and hypothalamus and called traumatic chiasmal syndrome. We report a patient with traumatic chiasmal syndrome caused by a severe traffic accident.

A 25 year-old woman was referred for bitemporal visual field defects caused by a traffic accident two months before. Corrected visual acuity was 0.05 in the right eye and 1.2 in the left eye. Bilateral optic atrophy and relative afferent pupillary defect in the right eye were found. Magnetic resonance imaging revealed an enlarged optic chiasm. Computed tomography disclosed many fractures in the skull including the back wall of the sphenoid sinuses. She also suffered from diabetes insipidus and anosmia.

Traumatic optic neuropathy of the optic chiasm is a rare condition which can be differentiated from neuropathy in the optic canal by considering the patterns of visual field defects and their accompanying signs.