According to the American Academy of Ophthalmology, the average person can see roughly ten million different colors. That range of perception is what we call the visible spectrum—the portion of light our eyes are sensitive to. For the most part, people see the same color range. But as of last Friday, there are five individuals who’ve seen a color that no one else on Earth can perceive. The reason? A remarkably precise laser technique that targets specific cells in the retina.
How Human Vision Works, and Its Limitations
Our eyes detect what’s known as the visible spectrum—light with wavelengths between about 380 and 750 nanometers. Anything below that is ultraviolet, and anything above is infrared, both of which are invisible to us. Our ability to see those wavelengths is thanks to cone cells in the retina. These are light-sensitive photoreceptors tuned to different parts of the spectrum. When they’re activated, they send signals to the brain, which decodes them into the colors we see.
S cones respond to short wavelengths, which means they’re tuned to blues. M cones pick up medium wavelengths—think greens. L cones handle the long ones, like reds.
But it’s not as simple as each cone sticking to its own lane. Their sensitivity ranges overlap quite a bit. M cones, for instance, will still respond to some of the longer wavelengths in the blue range, just like S cones can catch the shorter end of green. As Ren Ng, a professor of electrical engineering and computer science at the University of California, puts it, “There’s no natural light that stimulates only the M cones. When they light up, at least one or two other types are firing too.”
The Color-Striking Experiment
The idea behind the experiment builds on exactly that overlap: What if scientists could isolate and activate just one type of cone? That’s the approach researchers at the University of California took. They carefully mapped each participant’s retina, pinpointed the M cones, and then used tiny pulses of laser light to stimulate only those cells. The technique they developed has been nicknamed “Oz,” a nod to The Wizard of Oz and its famously vivid Emerald City.
After going through the experiment, participants were able to witness a brand-new color they’ve dubbed Olo. Out of the five who took part, three were actually co-authors of the study—including Ren Ng himself—and the other two were fellow researchers from the University of Washington. They describe “olo” as a kind of supercharged blue-green, something with a level of saturation that simply doesn’t exist in our everyday color wheel.
Ng says the closest digital comparison would be the color code #00ffcc—but don’t get your hopes up trying to see it on your phone. That screen just can’t do it justice. Why? Because your brain has never processed a signal like this before. It’s not just outside the box—it’s off the palette.
To make sure that everyone was truly seeing a color outside the range of normal human vision, the researchers ran color-matching tests. They compared “olo” to a standard blue-green laser, tweaking it by mixing in white light to either boost or tone down the saturation. The results were crystal clear: when white light was added to “olo,” it started to look just like the laser color.
All participants reported the same thing, confirming that “olo” isn’t just rare—it sits beyond the reach of what the human eye can typically perceive. In other words, it’s not just a new shade—it’s a total color curveball.
What This Means for the Scientific Community
As of today, the real-world applications are limited. According to Scientific American, the lead researcher and his team are dreaming big: screens that could scan your retina and show you images or videos in colors humans were never meant to see. Sci-fi, meet science fact.
Still, this breakthrough could carry more weight in other fields. Think of technology that helps people who are blind perceive colors in a new way, or systems that let us “borrow” the vision of another species, experiencing the world through their eyes. Pretty wild, right?
There’s just one catch: the Oz Effect doesn’t last. It’s not permanent. So while it’s cool to see the impossible, it’s still a fleeting glimpse behind the color curtain.
