iodopsin
noun
io·dop·sin ˌī-ə-ˈdäp-sən 
: a photosensitive violet pigment in the retinal cones that is similar to rhodopsin but more labile, is formed from vitamin A, and is important in daylight vision
Word History
Etymology
iod- (from Greek ioeidḗs "violet-colored") + -opsin (in rhodopsin) — more at iodine
First Known Use
1938, in the meaning defined above
Medical Definition
iodopsin
noun
io·dop·sin ˌī-ə-ˈdäp-sən
: a photosensitive violet pigment in the retinal cones that is similar to rhodopsin but more labile, is formed from vitamin A, and is important in photopic vision