The unique visual system of the mantis shrimp

Mantis shrimp may not be the usual topic of discussion in ophthalmology, but they are living proof that there is more to the world than meets the eye. Mantis shrimp have one of the most complex visual systems on Earth. Not only do they have 12-channel colour vision, putting our three channels to shame, but they also perceive polarisation, a channel of visual information hidden from our eyes. It is fair to say that mantis shrimp see the world very, very differently from us.

Despite their name, mantis shrimp are not shrimp at all, but rather a distant relation of crabs, lobsters and other crustaceans (figure 1). They live in burrows on the sea floor and can be found in oceans across the globe, except for at the poles.