A team of scientists is claiming to have discovered a new colour no human has ever seen before.
And they believe that the results could help further studies of colour blindness.
According to a story from the BBC, the findings, published in the journal Science Advances, follow an experiment in which researchers in the US had laser pulses fired into their eyes.
The article said that, by stimulating specific cells in the retina, the participants claim to have witnessed a blue-green colour that has been named “olo”.
Study co-author Professor Ren Ng, from the University of California, described the results as “remarkable”, but other experts have said the existence of a new colour is “open to argument” and interpretation.
Prof Ng, one of five people to taken part in the experiment, told BBC Radio 4’s Today programme that olo was “more saturated than any colour that you can see in the real world”.
“Let’s say you go around your whole life and you see only pink, baby pink, a pastel pink,” he said.
“And then one day you go to the office and someone’s wearing a shirt, and it’s the most intense baby pink you’ve ever seen, and they say it’s a new colour and we call it red.”
During the team’s experiment, researchers shone a laser beam into the pupil of one eye of each participant.
The five participants – four male and one female – all had normal colour vision.
They looked into a device called Oz which consists of mirrors, lasers and optical devices.
The retina includes cone cells, which are cells responsible for perceiving colour.
There are three types of cone cells in the eye – S, L and M – and each one is sensitive to different wavelengths of blue, red and green respectively.
According to the research paper, in normal vision, “any light that stimulates an M cone cell must also stimulate its neighbouring L and/or S cones”, because its function overlaps with them.
However, in the study, the laser only stimulated M cones, “which in principle would send a colour signal to the brain that never occurs in natural vision”, the paper said.
This means the colour olo could not be seen by a person’s naked eye in the real world without the help of specific stimulation.
To verify the colour observed during the experiment, each participant adjusted a controllable colour dial until it matched olo.
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