Visual evoked potentials during surgery

Abstract

Publisher Summary This chapter explores that the visual evoked potential (VEP) recorded from the occipital scalp reflects the activation of fibers arising from the area 8–10o central to the macular region of the retina. It reviews that VEPs are sensitive to vascular insults that affect the visual pathway. Transient ischemic episodes involving the carotid artery are associated with amplitude reductions of a flash-evoked VEP to the ipsilateral eye. The chapter discusses that VEP demonstrating a complete absence of an occipital response, despite the presence of a normal electroretinogram (ERG), indicates the damage of the optic nerve or conduction pathway. VEPs have been used for many years to compare preoperative and postoperative visual function. It reviews the further strengthening of decompression theory, studies have also shown that VEP changes were reversible by filling the space occupied by the excised lesions. Testing of visual pathway function in severely injured patients or even during craniomaxillofacial reconstructions, using VEPs and ERGs has been shown to be a reliable method of verifying the presence or absence of visual pathway function regardless of any pathology. The chapter concludes that there is evidence to suggest that the visual system can be successfully evaluated with VEPs between the preoperative and postoperative stages. More importantly, postoperative improvements in VEPs correlate directly with the improvements in visual function.