Melanopsin photoreception contributes to human visual detection, temporal and colour processing

The visual consequences of melanopsin photoreception in humans are not well understood. Here we studied melanopsin photoreception using a technique of photoreceptor silent substitution with five calibrated spectral lights after minimising the effects of individual differences in optical pre-receptoral filtering and desensitising penumbral cones in the shadow of retinal blood vessels. We demonstrate that putative melanopsin-mediated image-forming vision corresponds to an opponent S-OFF L + M-ON response property, with an average temporal resolution up to approximately 5 Hz, and >10x higher thresholds than red-green colour vision. With a capacity for signalling colour and integrating slowly changing lights, melanopsin-expressing intrinsically photosensitive retinal ganglion cells maybe the fifth photoreceptor type for peripheral vision.