Flash evoked cortical and subcortical potentials in neuro-ophthalmology

Visual evoked cortical and sub-cortical potentials are complementary to the electroretinogram in neuro-ophthalmology. By combining monocular stimulation with recordings from over the visual cortex of each cerebral hemisphere it is possible to accurately locate lesions which are both pre and post chiasmal. Chiasmal lesions can also be correctly identified using these techniques. The visual evoked sub-cortical potential, probably arising from a lateral geniculate or tectal site allows further post chiasmal variation. Flash and pattern reversal stimulation provide different information about the functioning of the visual system including the primary visual cortex and the association areas.