Most sensitive colour vision

The average human eye can perceive a million different colours. Our powers of colour vision derive from three types of cone cells each responsive to different wavelengths of light. Our brains combine the signals to produce the perception of colour. Work completed by neuroscientist Gabriele Jordan at the University of Newcastle, UK, proved that some people have four cones, enabling them to see more colours – 99 million or more, in fact. Jordan and her team constructed a test in which three subtle colour circles flashed on a screen. To a person with normal vision, these would appear the same. Only one person got every test 100% correct – an English female doctor known only as "cDa29", in possession of the world's most sensitive colour vision so far measured.