As an ex army ip i remember something about binocular vision only being important for depth perception to about 2 feet, after that it is all monocular cues. I vagualy remember an ancroynym for the monocular cues: GRAM and subsets like KITO, LVV, motion parallax. Point of this rambling post is that you dont need 2 eyes for depth perception or distance estimation. Google it, I am too lazy to provide an actual reference.