PURPOSE: To report longitudinal retinal nerve fiber layer (RNFL) thickness measurements using optical coherence tomography (OCT) in a patient with traumatic optic neuropathy. DESIGN: Observational case report. METHODS: A 14-year-old boy with severe optic nerve trauma had repeated OCT scans of the peripapillary retinal nerve fiber layer at 3 days, 20 days, 40 days, and 70 days after injury. RESULTS: There was gradual loss of nerve fibers as shown by the OCT color-coded map, RNFL thickness profile, and RNFL thickness measurements around the optic disk. At 70 days of follow-up, severe thinning of the RNFL was observable. CONCLUSIONS: These findings suggest that OCT is able to assess and monitor axonal loss after traumatic optic neuropathy.