Scientists reveal never-before-seen color by targeting specific eye cells

Scientists trick the eye to reveal a never-before-seen color

Discovery of "olo" could one day help people with color blindness see in a new way

Researchers at the University of California, Berkeley, have enabled five people to see a brand-new color—an intensely vivid blue-green hue never before experienced by the human eye. This new shade, dubbed “olo”, was produced by selectively stimulating just one type of cone cell in the retina, revealing how precise optical manipulation could expand the way we perceive color.

The experiment is being hailed as a milestone in color vision research, and it may lead to future applications in treating color vision deficiencies.

How color vision works—and how scientists bent the rules

Under normal conditions, human eyes rely on three types of cone cells to perceive color:

• S-cones (sensitive to blue)

• M-cones (green)

• L-cones (red)

These cones often overlap in their light sensitivity, especially in the blue-green region of the visible spectrum. This means that when you see a teal or turquoise shade, multiple cones are activated simultaneously, making it hard to isolate what one cone “sees” on its own.

But what if only one cone type was stimulated? That’s the question posed by Ren Ng and his team at UC Berkeley.

Creating a new color: The birth of "olo"

Ng and his colleagues worked with researchers behind an existing device called Oz—a precision laser tool that can stimulate individual cone cells. They modified Oz to deliver targeted light to a cluster of approximately 1000 M-cones, without activating neighboring cone types. This created a signal strong enough for the brain to register a color perception from just one cone class.

The result: all five participants reported seeing a brilliant, unfamiliar color—an intense blue-green that doesn’t exist on the standard color wheel.

“It’s hard to describe; it’s very brilliant,” said Ng. The team named the color “olo.”

To validate the discovery, participants performed a color-matching test. They adjusted a second color until it matched their perception of olo, consistently landing on an intense teal. In a follow-up, when asked to dilute olo or teal by adding white light, they all had to dilute olo—confirming it was the more vivid and saturated of the two.

A breakthrough with medical potential

While the discovery of a new color is intriguing on its own, the findings could have major implications for vision science and medicine, particularly in addressing red-green color blindness.

According to Andrew Stockman of University College London, the technique may one day help distinguish between overlapping cone responses that cause this type of color vision deficiency.

“Stimulating one cone type over the other could allow people to experience shades they previously couldn’t,” said Stockman. However, he emphasizes that clinical trials are needed to test this application.

Expanding the boundaries of visual perception

The research not only opens up new conversations around how humans perceive color, but also raises philosophical questions about what colors we might be missing. It demonstrates that our visual reality is limited by biological wiring, and with the right tools, new perceptual experiences may be unlocked.

As technology advances and precision optics improve, this breakthrough could pave the way toward customized vision solutions for people with visual impairments, and even expand human sensory perception beyond what evolution has provided.

Stay with The Horizons Times for more on vision science, optical technology, and the future of human perception.