For starters, they usually remain in the twilight zone, several hundred metres beneath the water's surface. Here, there is enough light for a good set of eyes to be useful. They therefore have a good set of eyes. They even point upwards to some extent so that they can look skyward and soak up as much light as possible. Prey such as small crustaceans and fish can be spotted by the shadow they cast. These eyes are also tubular so it's all quite similar to our very own Pacific Barreleye Fish, they just haven't taken it to quite such a ridiculous extent.