My dad's only reference to fish eye's was simple....."Fish don't have eyelids." reminding me, as a kid, to pay more attention to shady spots than those in sunlight.

Personal observation.....fish may have the ability to look downward, but if you have ever watched fish, they almost always turn on their side to watch things beneath them. The other option they use frequently in the salt is to stand on their head.

Those gill plate rakings on bottom-feeding chinook also show that they will dig out their prey (candle fish) after lying on their side observing them.