A binocular adaptive optics visual simulator has been devised for the study of stereopsis and of binocular visionin general. The apparatus is capable of manipulating the aberrations of each eye separately while subjectsperform visual tests. The correcting device is a liquid-crystal-on-silicon spatial light modulator permitting thecontrol of aberrations in the two eyes of the observer simultaneously in open loop. The apparatus can be operatedas an electro-optical binocular phoropter with two micro-displays projecting different scenes to each eye.Stereo-acuity tests (three-needle test and random-dot stereograms) have been programmed for exploring theperformance of the instrument. As an example, stereo-acuity has been measured in two subjects in the presenceof defocus and/or trefoil, showing a complex relationship between the eye’s optical quality and stereopsis.This instrument might serve for a better understanding of the relationship of binocular vision and stereopsisperformance and the eye’s aberrations.