Assessment of Magnocellular and Parvocellular Pathways in Early- versus Late-Onset Amblyopes Using Motion and Color VEP

Abstract

Aim: Studies in nonhuman primates indicate that monocular visual deprivation starting at different ages has different effects on the parvocellular and magnocellular pathways. We examined whether subjects with strabismic amblyopia of onset before (early) or after 18 months (late) of age have different electrophysiological responses to motion onset and color appearance stimuli. Method: Motion onset VEPs were recorded in 15 early and 12 late onset strabismic amblyopes and 19 normal subjects using an achromatic 0.8-cpd vertical square wave grating.