Introduction:
The aim of the work is to compare the visual evoked potentials in patients with acute optic neuritis.

Material and methods:
A retrospective review of 49 patients (53% of women, median age: 32 yrs ± 13) who had history of sudden unilateral visual loss was carried out. The patients were divided into three groups: retrobulbar optic neuritis associated with multiple sclerosis, retrobulbar neuritis without demyelinating disease and optic disc edema. The control group comprised healthy, young adults. Comparison of the P100 wave latencies and amplitudes among affected eyes and the control group, and between the affected and the unaffected eye in every patient was statistically analyzed by the U Mann-Whitney test and the Wilcoxon test. The statistically significant p value < 0.05

Results:
64 affected eyes and 34 control eyes were evaluated. The mean P100 latency was the most prolonged in the first group (optic neuritis with confirmed multiple sclerosis). There were no statistically significant differences of amplitudes among the three groups. The P100 values differ significantly (p < 0.01) between the affected eyes and the control eyes. Inter-ocular differences in peak latencies (for both stimulus check size 1° and 15’) were significantly increased in the group with multiple sclerosis (respectively p = 0.005; p = 0.026).

Conclusions:
VEPs can be used to demonstrate prolonged P100 latency in patients affected by acute optic neuritis related to demyelination, but VEP only is not sufficient to clearly define the etiology of the optic neuropathy. Prolonged VEP latencies are a more accurate indicator of an inflammatory disorder of the optic nerve than P100 ampli-tudes.