Opsin can be referred to as Rhodopsin, Encephalopsin, and Melanopsin among others and can be seen in the eyes, brain, and skin.
Rhodopsin (Rh1, OPN2, RHO)  expressed in rod cells, used in night vision Panopsins are found in many tissues (skin, brain, testes, heart, liver, kidney, skeletal muscle, lung, pancreas and retina). They were originally found in the human and mouse brain and thus called encephalopsin. 
