visual purple

rho·dop·sin   (rō-dŏp'sĭn)    n.  The pigment sensitive to red light in the retinal rods of the eyes, consisting of opsin and retinene. Also called visual purple. [rhod(o)- + Greek opsis, sight; see -opsis + -in.]

Main Entry: rho·dop·sin
Pronunciation: rO-'däp-s&n
Function: noun
: a red photosensitive pigment in the retinal rods of marine fishesand most higher vertebrates that is important in vision in dim light, is quickly bleached by light to a mixture of opsin and retinal, and is regenerated in the dark called also visual purple

rhodopsin rho·dop·sin (rō-dŏp'sĭn)
n.
A thermolabile protein that is sensitive to red light and is found in the external segments of the rods of the retina of the eye. Also called visual purple.