Underwatertimes.com News Service - October 17, 2007 17:15 EST

Goldfish have specialised eyes which give them vision like wearing sunglasses to improve sight when catching prey, new research has discovered.

Scientists at the University of Manchester say light sensitive cells within the fish's retina are able to detect polarised light, improving visual contrast.

It is the first time such a discovery has been made in vertebrates.

Dr Nicholas Roberts, from the university's Photon Science Institute and the School of Physics and Astronomy, said: "Just as fishermen wear Polaroid sunglasses to help improve contrast, many different animals - including fish - have evolved to do the very same thing without the need of sunglasses.

"It is a surprisingly common ability throughout the animal kingdom.

"Vision is the primary sense of many animals and the way they see their world is of fundamental importance to understanding aspects of their behaviour.

"Numerous animals have amazing visual abilities, which allow them to see the world in very different ways. One such ability is polarisation vision."

Researchers hope it may lead to new developments in man-made microscopic detection or information display technologies.

The findings are published in the Biophysical Journal.