Mind

Scientists found a way to let people perceive an intense blue-green hue unlike anything they had seen before – and the technique could help people with colour blindness

By Carissa Wong

10 December 2025

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We perceive colour using input from the cone cells in our retinas

Shutterstock/Kitreel

In April, a team of researchers reported a device enabled them to witness an intense green-blue colour that had never been seen by humans before. After the announcement, they were bombarded by requests from the public to see the colour for themselves.

The device could enable people with some kinds of colour blindness to experience typical vision, and could even allow people with typical vision to perceive a wider range of hues. “We’re very interested in expanding the dimensions of the colour experience,” says Austin Roorda at the University of Waterloo in Canada.

In most people, the retina at the back of the eye contains three types of cone cells – called S, M and L – that each detect light with a different range of wavelengths. Our brains create our perception of colour based on the signals from these three types of cones.