A light-sensitive calcium channel that is required for inositide-mediated Ca(2+) entry in the retina during phospholipase C (PLC)-mediated phototransduction. Required for vision in the dark and in dim light. Binds calmodulin. Trp and trpl act together in the light response, although it is unclear whether as heteromultimers or distinct units. Also forms a functional cation channel with trp-gamma. Activated by fatty acids, metabolic stress, inositols and GTP-binding proteins.