[Diagnostic value of visual evoked potential in toxic and nutritional optic neuropathies].

BACKGROUND

Toxic/nutritional optic neuropathy (TON) is a diagnosis of exclusion after an extensive work-up. In cases of a non-contributory history or atypical presentation, formal diagnosis can sometimes be difficult and delay management. The goal of this study was to evaluate the diagnostic value of checkerboard visual evoked potentials (VEP) for toxic/nutritional optic neuropathy. The working hypothesis was that, in TON, VEPs are more affected than best corrected visual acuity (BCVA). We assumed that, for BCVA ≥ 1/20 and ≥ 2/10, the 60' and 15' checkerboard VEP responses would be respectively affected.

METHODS

This was an observational, single-center, retrospective study. We collected demographic data, self-declared data on alcohol and tobacco use, data from the ophthalmologic examination, and notably the BCVA as well as the 60' and 15' VEPs. We divided the subjects into two visual acuity groups, one with BCVA ≥ 1/20, for which we reported the 60' VEP results, and the other with BCVA ≥ 2/10, for which we reported the 15' VEP results.

RESULTS

Sixty-five patients were included. For those with BCVA ≥ 1/20, 64.2% of the 60' VEPs were undiscernible from background noise. Similarly, 95.3% of the 15' VEPs were undiscernible for the BCVA ≥ 2/10 group.

CONCLUSION

Our study results indicate that, in TON, VEPs are more affected than the visual acuity would suggest. This may be a diagnostic pattern suggestive of TON.