Do the two eyes constitute separate visual channels?

A two-interval forced-choice procedure was used to study monocular detection of a briefly presented low-contrast sine-wave grating pattern. Uncertainty about which eye was stimulated degraded detection performance for stereo-blind observers but not for normal ones. These results relate to selective monocular suppression, stereopsis, and other forms of binocular interaction and suggest the level at which inputs to the two eyes are combined neurally.