Moirés maintained internally by binocular vision

Moiré patterns in depth are reported when spatially periodic stimuli are viewed stereoscopically. Near-vertical square-wave gratings with horizontal disparity effected by orientation difference produce a 'venetian blind' effect. A single grating is observed divided into horizontal layers, the number of layers being a direct function of orientation difference. Lines within each layer are slanted with respect to the frontoparallel plane, becoming more so with increasing orientation difference. Subjects with stereo deficits report a decreased effect. Quantitative reports implicate stereoscopic mechanisms responsible for this unique, internal preservation of moiré patterns.