Ishihara Colour Vision Test Photo: Ishihara
Why do we humans and some other primates see colour, and what are the implications of being colour vision deficient?
Males are 20 times more likely to be colour vision deficient, and it all comes down to the sex chromosomes. Professor of ophthalmology and colour vision researcher at the University of Washington in Seattle Dr Jay Neitz explains the evolution of colour vision, and Don McPherson has developed glasses that correct colour vision impairment to help people see the full spectrum. And we visit Newlands Intermediate school and meet vision technician Helen Dirkze testing students' ability to see different colours.
