text: *Melanopsin: in vertebrate retina, mediates pupillary reflex,  involved in regulation of circadian rhythms
  *Photopsin: reception of various colors of light in the cone cells of vertebrate retina
  *Rhodopsin: green-blue light reception in the rod cells of vertebrate retina
  *Protein Kinase C: mediates photoreceptor deactivation, and retinal  degeneration
  *OPN5: sensitive to UV-light