Electroretinogram and visual-evoked potentials in children with optic nerve coloboma.

The aim was to evaluate alterations in Visual-Evoked Potentials (VEP) and Electroretinogram (ERG) and discover whether these tests are useful for determining residual visual acuity in cases where a patient is unable to collaborate. Flash and, when possible, Transient Pattern Reversal Visual-Evoked Potentials and Maximal Response ERG were recorded in 8 children (under three years old) affected by different aspects of optic nerve coloboma. None of them had visual acuity evaluated because of poor collaboration. All examinations were carried out using skin electrodes. Amplitude of the a and b component of ERG, amplitude, morphology and latency of the major components of Flash VEP and amplitude and latency of P100 Pattern Reversal VEP were evaluated. Four of the patients were examined three years later and visual acuity was compared with the previous electrofunctional results. Alterations in ERG were found only in the case of significant retinal anomalies (great coloboma, retinal detachment), huge alterations were found in both Flash VEP and in Pattern Reversal VEP. The retrospective study of VEP traces and visual acuity showed a good correlation between electrofunctional data and visual capability. Electrofucntional examinations can identify important conductive retinocortical anomalies. The possibility of correlating electrophysiological results with residual visual acuity is important for rehabilitative management in such optic disc malformations.