Binocular vision tested with visual evoked potentials in children and infants

Evoked potentials (EP's) in response to phase-alternating gratings were recorded from normal and stereoblind or stereodefective subjects (adults and children) under monocular and binocular viewing conditions. The amplitude of the binocular EP was found to exceed the larger monocular EP in normal but not in stereodefective subjects, no matter whether the amplitudes of the two monocular EP's were the same or not. This finding provides an objective method for screening out defects of binocular vision. EP's recorded from a group of infants 2 to 18 months old suggest that a larger amplitude of the binocular EP, as compared with the monocular EP's, is the norm even in the earliest period of life.