A 19-year-old man developed visual loss in the left eye 1 day following a martial arts kick to the head. Vision worsened over a week, when visual loss was noted in the right eye without further trauma. The fundus was initially normal, but visual field testing showed temporal depression right eye with diffuse depression left eye, and traumatic chiasmopathy was suspected. Magnetic resonance imaging (MRI) of the brain demonstrated an enlarged chiasm with intrinsic signal abnormality, but no enhancement. Treatment with intravenous corticosteroids and hyperbaric oxygen therapy did not result in visual improvement. Ancillary testing for atypical optic neuritis was negative, but testing for LHON was positive for the 11778 mutation. This case raises the question of trauma as a precipitating factor for LHON and illustrates the rare occurrence of intrinsic signal abnormalities of the chiasm in this disorder.
Keywords: Chiasmal enlargement; LHON; MRI abnormality; trauma.