These findings showed that melanopsin ganglion cells are intrinsically photosensitive, and thus constitute a third class of photoreceptors in the mammalian retina, joining the better known rod and cone photoreceptors.
These findings showed that melanopsin ganglion cells are intrinsically photosensitive, thus named intrinsically photosensitive Retinal Ganglion Cells (ipRGC). They constitute a third class of photoreceptors in the mammalian retina, beside the already known rod and cone photoreceptors.