If you shine a light into one eye both pupils will constrict. the best explanation for this is a small portion of light always enters the other eye this in fact does not occur and information from both eyes is always separated information from one eye is directly and immediately transferred to the other eye to maintain alignment of the eyes sensory input from the retinas of both eyes converges at the optic chiasm and information from each eye is delivered to both the left and right sides of the brain