Pattern visual evoked potentials in traumatic optic neuropathy.

To evaluate the characteristics of pattern visual evoked potentials (PVEPs) in traumatic optic neuropathy (TON) compared with optic neuritis (ON), we retrospectively studied 47 patients with TON and 64 patients with unilateral ON. PVEPs elicited by the stimulation with 3 reversals/s were recorded in all patients. A PVEP could be recorded in 29.8% of the TON patients and 49.6% of the ON patients at their first visit. In the 14 patients with TON and recordable PVEPs, the mean amplitude ratio (affected/fellow eye) was 0.29 +/- 0.03 (SE) and the mean delay of the peak latency was 17.9 +/- 2.9 ms. In the 30 patients with ON and recordable PVEPs, the mean amplitude ratio was 0.48 +/- 0.04 (SE) and the mean delay of the peak latency was 23.5 +/- 2.5 ms. The amplitude ratio was significantly lower in patients with TON than in those with ON.