Visual evoked potential: Enhancing its utility

The VEP can be used to assess the contributions of specific neuronal populations to visual processing heretofore evaluable only by microelectrode or psychophysical techniques. The first approach is not feasible in humans. The second is exquisitely sensitive and reliable when trained observers are studied. Psychophysical methods are subjective, requiring subject cooperation and understanding of threshold detection. These studies are often prolonged, with results inconsistent among patients in the clinic. The VEP offers an objective assessment of visual performance and permits quantification of deficits in acuity, contrast, and adaptation (especially when real-time retrieval is used), when one measures more than the latency.