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 abundant and uniform in the anterior-posterior and oblique cells of the retinulae, with some expression in the proximal cells. There is no expression in the dorsal rim retinulae (at protein level). Belongs to the G-protein coupled receptor 1 family. Opsin subfamily.