The barreleye fish
, Macropinna microstoma
, has tubular eyes (the green globes in the image) and a transparent shield protecting its upward-looking eyes. The glasshead barreleye fish, Rhynchohyalus natalensis, is a closely related species which is not found here in the Northeast Pacific.
Recently, scientists discovered that the glasshead barreleye fish’s eyes, which are cylindrical with a conventi…onal refractive lens on top, also have a second retina. Bioluminescence from deep-sea prey enters through a cornea and hits a separate silvery surface, to be focused on the second retina. The fish can therefore see objects above it with its conventional cylindrical eye, and detect other deep-sea creatures to the side and below via the reflector eye looking sideways. Read more about these amazing eyes:
You can also see our YouTube video about the barreleye here http://ow.ly/uU3BE