Leber's hereditary optic neuropathy after head trauma: a case report

A previously healthy 34-year-old man sustained multiple skull fractures in a traffic accident. Radiological findings and visual field examination did not detect any abnormality. Shortly after the accident, he noticed blurred vision in both eyes. Six months after the accident, he gradually developed disturbance of visual acuity in the right eye. His best corrected visual acuity (BCVA) was 0.8 OD and 1.2 OS and brain MRI did not show any abnormality, while Humphrey visual field analysis demonstrated right homonymous hemianopsia. Two months after the initial presentation, his BCVA showed 0.1 OD and 0.08 OS. Visual field examination suggested that both right homonymous hemianopsia and left blind spot had become enlarged. Mitochondrial DNA analysis demonstrated G11,778A mutation and a diagnosis of Leber's hereditary optic neuropathy (LHON) was made. A few reports have documented mild acute insult to the head or blunt optic trauma as triggers of optic neuropathy in subjects with LHON. Although, the precise mechanism of LHON following trauma remains unknown, it appears that an acute insult may be sufficient to precipitate neuropathy in the optic nerve already compromised by mitochondrial dysfunction. Asymptomatic carriers should be advised to avoid possible precipitating factors such as head trauma.