Laser Exposure Unlocks a Previously Unseen Color for Humans

Just when we think we’ve experienced the full spectrum of visible color, scientists have reportedly discovered a way to reveal a brand-new hue to the human eye — a color that’s never before been perceived. They’ve named it Olo.

Before diving into the details, it’s worth noting how participants in the study described this color: an intensely vivid, almost surreal blend of blue and green — a tone so striking that it left viewers stunned.

While that description offers some sense of it, it likely doesn’t convey the awe of encountering a completely unfamiliar color — one that lies outside the usual boundaries of human color perception. Researchers even shared an approximation of the shade with The Guardian, though it’s still just a visual placeholder for something profoundly novel.

How Does One “See” Olo?

To witness this new color, participants had a carefully calibrated laser beam directed into their eye. But understanding this breakthrough requires a brief refresher on how human vision works.

Our eyes use two primary types of photoreceptor cells: rods and cones. Rods assist with night vision, while cones handle color. There are three cone types, each sensitive to specific light wavelengths — long (L), medium (M), and short (S), corresponding roughly to red, green, and blue light.

Typically, we see colors based on how these cones respond to combined light wavelengths. The M cones, which respond to green light, don’t have a natural monochromatic light source that activates them alone without also affecting the L or S cones. This overlap has, until now, limited our ability to isolate M cone activity and reveal unique color experiences.

Researchers from the University of California, Berkeley and the University of Washington collaborated with ophthalmologists to overcome this hurdle. Their technique, dubbed Oz, uses adaptive optics optical coherence tomography to scan and map the retina at a cellular level, precisely locating the M cones.

As participants fixate on a visual target, the system uses infrared light to track microscopic eye movements in real time. With this data, it calculates how much stimulation each cone requires to produce the intended effect.

Then, using a method called adaptive optics scanning light ophthalmoscopy (AOSLO), the system delivers ultra-precise, brief flashes of laser light directly to thousands of individual M cones.

Olo: A Color Born from Innovation

By selectively targeting these cones, the researchers were able to bypass natural vision limitations and create a new perceptual experience — a color never encountered in the natural world.

“This isn’t just a variation of a known color — it’s something entirely different,” said vision scientist Austin Roorda, the lead author of the study, published in Science Advances. “Any color we’ve seen before pales in comparison to the experience of seeing Olo.”

A Divisive Discovery in the Scientific Community

Not all experts agree on the implications. Kimberly Jameson, a color vision researcher at the University of California, Irvine, praised the work as a “remarkable milestone.” However, John Barbur from St George’s, University of London, expressed skepticism, asserting that Olo is not a genuinely new color and questioning the practical value of the study.

Regardless of the debate, this marks the first successful attempt to manipulate individual cone responses across a wide retinal area to shift a viewer’s perceptual experience.

Looking ahead, the research team aims to explore whether similar techniques could help address color blindness or even enhance normal vision in new ways.

Read the original article on: New Atlas

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