This is one of the most interesting animals I've learned about recently. This deep water fish has a crystal clear lens for the skin covering its head. So its head is completely transparent. And, even more bizarre, its eyes are completely encased in this fluid filled lens. The eyes don’t touch the surface of the lens. What looks like eyes are actually organs used for smell.
This fish has specialized eyes that, as of yet, have received little research. Here’s what’s been published. The eyes are tubular with a large lens. The lens is the green curved cap you see in the picture. The eye is not round like our eye, but is shaped like a barrel. This produces delicate sensitivity to light which is necessary since the fish lives between 2,000 and 2,500 feet below the surface. The eyes are more like a telescope than a wide angle lens.
It is suggested that the reason the eyes point up is so the fish can see the silhouette of food floating or swimming above its depth. Until 2009 scientists didn't think the eyes could move so they didn’t understand how it could feed without seeing to guide its mouth. Then, while under observation, it moved its eyes forward when it was going in for the kill. The clear cover is also believed to protect the eyes from stinging jellyfish. Another complex biological system engineered for deep water. God is amazing!