Optics which are sensitive to different aspects of light. Rod cells are sensitive to the intensity of light over a wide frequency range, thus are responsible for black-and-white vision. Rod cells are not present on the fovea, the area of the retina responsible for central vision, and are not as responsive as cone cells to spatial and temporal changes in light. There are, however, twenty times more rod cells than cone cells in the retina because the rod cells are present across a wider area. Because of their wider distribution, rods are responsible for peripheral vision. In contrast, cone cells are
Intrinsically photosensitive retinal ganglion cells Intrinsically photosensitive retinal ganglion cells Intrinsically photosensitive retinal ganglion cells (ipRGCs), also called photosensitive retinal ganglion cells (pRGC), or melanopsin-containing retinal ganglion cells (mRGCs), are a type of neuron in the retina of the mammalian eye. The presence of ipRGCs were first noted in 1923 when rodless, coneless mice still responded to a light stimulus through pupil constriction, suggesting that rods and cones are not the only light sensitive neurons in the retina. It wasn't until the 1980s that advancements in research on these cells began. Recent research has shown that these retinal ganglion cells, unlike other retinal ganglion cells,