Visual pigments are the light-absorbing molecules that mediate vision. They consist of an apoprotein, opsin, covalently linked to cis-retinal. May play a role in photoperiodic photoreception. In the retina, expression is essentially uniformly distributed, but a higher level is seen in the dorsal region of the retina and in the dorsal rim retinulae. Belongs to the G-protein coupled receptor 1 family. Opsin subfamily.