Sharp changes in ambient luminance are known to modulate the size of the pupil, regulating the amount of light that enters the eye and reaches the retina. This process, known as pupillary light reflex (PLR), allows the retina to rapidly adapt to different luminance conditions. While PLR has been widely characterized in terms of its neural underpinnings as well as its clinical and behavioral significance, one simple question is still pending: does PLR directly modulate the output of the retina? To answer this question, we performed in vivo 2-photons calcium imaging in retinal ganglion cells (RGC) axons from one eye in the contralateral lateral geniculate nucleus (LGN), while providing dichoptic visual stimulation. Interestingly, we found that indeed pupillary constriction elicited by a sharp change in luminance is sufficient for generating robust evoked responses in the OFF-type RGCs, while transiently inhibiting the ON-type RGCs. The same responses were observed when the pupil constriction was driven by the stimulation of either the labeled (direct PLR) or the unlabeled eye (consensual PLR), suggesting that this process may support some aspects of early-stage binocular integration. Furthermore, we found that luminance changes that affect only the binocular part of the visual field are sufficient to generate both a direct and a consensual PLR, as opposed to local stimulation of the monocular part. Taken together, these findings point to a novel role for the PLR, as a process directly modulating the stream of the visual information and possibly enabling some forms of binocularity.