It is estimated that the human eye can see almost 10 million different colors. In a paper published in Science Advances, scientists described a precise laser setup that stimulated the retinas of five participants, three of which were co-authors of the paper, to perceive colors beyond the normal human visual range.

The procedure, called “Oz”, involved delivering minute doses of light to the cone cells in the eye responsible for detecting the color green. Each participant observed a saturated bluish-green color resembling teal, which the researchers named “olo”. The participants confirmed that olo was beyond the standard visual range by comparing it with a teal-colored laser and adjusting the saturation by subtracting white light.