The Visual Evoked Response a New Tool in Vision Research∗

The minute electrical discharges which occur in the visual cortex upon brief stimulation of the eye by light can be monitored by topical scalp electrodes and, aided by computer summation techniques, their waveform can be extracted and displayed for study. Various factors, both external and internal to the human subject, have been shown to influence the character of a given response. The visual evoked response (VER) has already been employed in laboratory investigations of such varied visual factors as amblyopia, color vision, intensity‐time relationships, metacontrast, dark adaptation and foveal characteristics. A relationship between the contrast of borders in the retinal image and the character of a specific temporal portion of the VER has been recently reported by Harter and White. This discovery may make possible the development of an objective, non‐verbal clinical test for refractive status.