Clinical aspects of the visually evoked potential.

The visually evoked potential (VEP) was studied in normal and abnormal human subjects, and in Rhesus monkeys. A relatively simple protocol for clinical VEP testing is described. The monkeys showed similar but smaller VEP responses compared to those obtained from human subjects. Central, but not paracentral or peripheral photocoagulation retinal lesions were associated with VEP abnormalities. The second, smaller wave of the response complex to 10 Hz flash stimuli corresponds to the primary evoked response, and is closely related to visual acuity. It was possible to recognize visually this VEP waveform and subjectively interpret the record correctly in 85% of eyes with regard to visual acuity. Therefore, the clinician can "read" the VEP record in response to non-patterned flash stimuli. This test was further validated in a series of patients with opacities of the ocular media. VEP promises to become a procedure of diagnostic and prognostic value in ophthalmology.