NOTE: This term and its definition were changed in RP-16-17 Addendum 4. Deletions have a strike-through. New text is bold.
Some retinal ganglion cells (melanopsin-containing) are photosensing and are believed to have a role in entraining the circadian clock as well as other hormone-mediated effects. These cells are not believed to contribute to visual perception.
A class of neurons on the inner surface of the retina that vary significantly in their size, connections, and responses. Some receive information from neurons connected to the rods and cones and pass visual response signals to the brain. Others (the intrinsically photosensitive retinal ganglion cells, ipRGC) are photosensitive and contribute primarily to nonvisual physiological processes and the pupillary light reflex.« Back to Definitions Index