We report results using a new stimulus for clinical testing of visually evoked potentials (VEPs). The stimulus was the modulation of the luminance of a large unpatterned field by a temporal pseudorandom binary sequence. The stimulus was similar to Gaussian white noise in that a large number of sinusoidal harmonics were presented concurrently. It has the important advantage that conventional signal averaging techniques can be used to analyze the VEP. Abnormal VEP responses were obtained when the stimulus was applied to patients with minimal macular and optic nerve disease.