ABSTRACT

Objectives:

To compare the results of pattern reversal visual evoked potentials (VEP) in the fellow eye of patients with unilateral non-arteritic anterior ischemic optic neuropathy (NAION) and in the eyes of age-and sex-matched healthy control group.

Materials and Methods:

Fellow eyes of 30 patients (study group) with unilateral NAION and 30 age-and sex-matched healthy controls (control group) were included in the study. Pattern VEP was recorded and the p100 latencies and amplitudes were obtained. Differences between groups were statistically evaluated using t-test.

Results:

In the study group, there were 16 (53.3%) men and 14 (46.7%) women, whereas there were 17 (56.7%) men and 13 (43.4%) women in the control group. Mean age of the patients in the study and control groups was 57.9±9.06 and 56.7±9.23 years, respectively. There was not any statistically significant difference regarding mean best-corrected visual acuity between the two groups (p=0.261). The mean P100 latency was 112.4±16.7 ms in the study group and 101.9±1.6 ms in the control group (p=0.03). P100 amplitudes were decreased in the study group compared with the control group (7.03±3.85 μV versus 9.63±2.6 μV) (t-test, p=0.003).

Conclusion:

In our study, we determined that P100 latencies were prolonged and P100 amplitudes were decreased in the fellow eyes of patients with unilateral NAION compared with the healthy control subjects. These data could suggest axon loss due to ischemia, influenced visual cortex response, or subclinical involvement of the fellow eye. These findings could also give a clue to predict the risk of contralateral involvement.