Scientists Claim Discovery of Never-Before-Seen Colour Through Laser Eye Stimulation

In a breakthrough that’s stirring both fascination and debate, a group of U.S.-based scientists say they have discovered a colour that no human has ever seen before. Dubbed “olo,” this vivid blue-green hue was observed during a unique experiment that used precise laser stimulation to activate specific cells in the human retina.

The findings, published in Science Advances, detail how researchers from the University of California and the University of Washington used a specially engineered device called Oz—a complex system of lasers, mirrors, and optics—to isolate stimulation to the eye’s M-cone cells, which are sensitive to green wavelengths. Under normal circumstances, these cones overlap in function with L and S cones, which perceive red and blue. As a result, the brain never receives an M-cone-only signal in natural vision—until now.

By firing highly controlled laser pulses into the eye, the researchers created a visual experience that bypassed this natural overlap. The result was a colour described as “more saturated than anything seen in the natural world,” according to study co-author Professor Ren Ng, who also participated in the experiment. “It’s like going from pastel pink to the most intense red you’ve ever seen,” he explained on BBC Radio 4.

Participants—five in total, including four men and one woman with normal colour vision—were asked to use a digital dial to match the new colour after seeing it. All reported seeing the same unique shade, confirming the consistency of the phenomenon.

Still, some experts remain cautious. Professor John Barbur, a vision scientist at City St George’s, University of London, praised the experiment’s technical achievement but questioned whether this truly qualifies as the discovery of a new colour. He argued that manipulating cone sensitivity can alter the perception of colour intensity rather than create entirely new colours.

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Despite the debate, the research could have broader implications, particularly for those with colour blindness. The ability to isolate and stimulate specific cones could lead to new therapies or tools to enhance colour perception in individuals who struggle to distinguish between hues.

Though olo cannot be seen with the naked eye without specialized equipment, the experiment opens the door to new understandings of how human vision works—and how much more of the colour spectrum may still be hidden from sight.