Sharks have an unusual organ called the ampullae of Lorenzini. This organ detects electromagnetic fields emitted when animals move. It allows them to see prey hiding in the sand as well as locate swimming prey very efficiently.
Sharks have a layer of crystals located behind their retinas called the tapetum lucidum that allows them to see around 10 times better than a human in low light. However, their depth is limited, as sharks can only see clearly about 50 feet ahead.