Study of Visual Evoked Potentials in Schoolchildren: A Promising Aid to Pediatric Ophthalmology.

Abstract

Background Visual evoked potential (VEP) is a noninvasive investigation conducted to identify abnormalities in the visual system. It is especially suitable for young children who are unable to express visual symptoms or participate in conventional vision tests. This study was undertaken to examine the VEP among schoolchildren to assess the functionality of their optic pathway. Methodology This short-term observational study was performed in the Clinical Neurophysiology Unit of the Physiology Department of a rural medical college. The study population consisted of 60 schoolchildren aged 7-12. Both eyes were examined for transient pattern reversal VEP recordingsusing a Recorders & Medicare Systems Electromyography-Evoked Potential recorder (RMS EMG-EP MARK-II Pvt. Ltd., Chandigarh, India). Results VEPs were analyzed for latency and amplitude of the main components, namely P100, N70, and N155. The results showedmarkedly extended P100 latency in33.33%, i.e., eight outof 24 eyes of standard (std.) III children. Similar latency prolongation was obtained in 36.36% (eight out of 22)eyes of std. IV, 30% (six of 20 eyes) of std. V, 13.63% (three of 22 eyes) of std. VI, and 50% (eight of 16 eyes) in std. VII and VIIIchildren. A markedly reduced P100 amplitude was observedin two of 20 eyes (10%) of std. V, two of 16 eyes (12.5%) in std. VII and VIIIchildren, amounting to a P100amplitude abnormality in5%eyesin toto. The interocular differences in all VEP parameters amongthe subjects were statistically insignificant. Conclusion In schoolchildren in whom normal latencies and amplitudes were obtained, the presence of reproducible VEPs indicated the normal functionalstatus of their visual pathway. On the other hand,in those children where alteredVEP findings were found, it hinted towardcomplementary informationthat they may have underlying ocular disordersthat were yet to be diagnosed. Hence, this study provides insight into the assessment of visual system function, which is primarily difficult in young children.