Visual evoked potential estimation of visual activity with a Laplacian derivation.

Visual acuity was estimated with visual evoked potentials in 13 healthy subjects. A Laplacian derivation of 5 electrodes was used to improve the signal-to-noise ratio and to enhance striate cortical activity selectively. In 6 subjects, the Laplacian derivation gave a more reliable estimation of visual acuity than did a single midline derivation. In the other 7 subjects, the quality of both estimations was comparable.