Visually evoked response. Use in neurologic evaluation of posttraumatic subjective visual complaints

Evaluation of subjective visual complaints unassociated with objective signs is a frequent problem in neurologic and ophthalmic practice. The visually evoked response (VER) is an important tool for separating the functional from the organic in patients claiming visual disturbance. In visual complaints associated with late posttraumatic epileptic activity, the VER can demonstrate an abnormality even in asymptomatic intervals. In complaints due to concussion, it demonstrates disorganized evoked responses initially and later a return of the normal resonse. It shows an abnormality in the occipital lobes during and after transient compression of the vertebral artery. A normal VER excludes all but trivial involvement of the visual system, symptomatic claims of the patient notwithstanding.