Most stereoblind persons with two healthy eyes do employ binocular vision to some extent, albeit less than persons with normally developed eyesight. This was shown in a study in which stereoblind subjects were posed with the task of judging the direction of rotation of a simulated transparent cylinder: the subjects performed better when using two eyes than when using their preferred eye. They appeared to judge the direction of rotation from the images in each eye separately and then to combine these judgments, rather than relying on differences between the images in the two eyes.[1] Also, purely binocular motion stimuli appear to influence stereoblind persons' sensation of self-motion.[2] Furthermore, in some cases each eye can contribute to peripheral vision for one side of the field of view (see also monofixation syndrome).