Electrodiagnosis in paediatric ophthalmogenetics.

In the present overview, practical application of the visual evoked potential (VEP) in paediatric neuro-ophthalmology is described across a wide range of ophthalmogenetic disorders, including albinism, Pelizaeus-Merzbacher disease and spastic paraplegia. The VEP approach is based on a four parameter subdivision of the electrophysiological response which includes, (1) amplitude (microV), (2) latency (ms), (3) waveform (component specificity), and (4) topography (potential distribution across the electrode array). In the case studies presented, evoked potential measures provide clinically useful and even at times invaluable insights concerning the presence, extent and type of visual pathway compromise. The four parameter subdivision along with age matched normative standards provides a sensitive and reliable means to facilitate detection and diagnosis of sensory anomalies in the developing visual system. The non-invasive electrophysiological assessment of visual function and its maturational course also provides early identification of affected family members as well as an objective measure of various treatment regimes which, particularly for the pre-verbal and non-verbal child, is critical for effective patient care.