Is that true? It seems that our eyes are mechanically capable of looking in divergent directions, what's the reason that we're not able to "uncross" them beyond looking straight ahead?
(Edit: Anecdotally I can confirm for myself that I'm not able to do it, so wondering if there's anyone that can.)
From a control system standpoint, if you have one control that rotates both eyes the same number of degrees left or right to determine gaze direction and another to rotate both eyes the same (positive) number of degrees inward to control fixation distance, you can't specify the left eye rotated left of center and the right eye right, even if each eye physically can rotate that way. Not sure if that's how eyes actually work though.
