Scientists at UC Berkeley created a technique called Oz. It lets people see a new color named olo. Olo is a bright blue-green shade that looks more vivid than any natural color. The technique uses tiny laser pulses to control cells in the eye. These cells, called photoreceptors, help us see colors.

The idea and the name for Oz come from The Wizard of Oz story. In the book, the Emerald City looks green because of special glasses. The researchers who built software to make Oz work say the new technique feels like a journey to see new colors. The system targets up to 1,000 photoreceptors at once. This helps scientists study how humans see colors.

How Oz changes vision

Humans see colors because of three types of cone cells in the retina. The retina is the back part of the eye. S cones see blue light, M cones see green, and L cones see red. Normally, M and L cones overlap, so no light can activate just M cones. The researchers wanted to activate only M cones and used lasers for this.

Oz needs a map of a person’s cone cells. Researchers at the University of Washington made this map. The map shows where S, M, and L cones are. Oz then uses a green laser to activate specific cones. By targeting mostly M cones, it creates olo. The laser can also mix cones to show full-color images. The display size is tiny, like a fingernail.

Five people saw olo and found it striking. They called it peacock green. It looked much brighter than a green laser pointer. The researchers tested what happens if the laser moves slightly off target. The color changed to a normal green.

Oz helps study eye diseases where cone cells die. It might also help colorblind people see more colors. The researchers say Oz shows the brain can handle new visual inputs. The technique opens new ways to understand vision and the brain.

The reserchers described the methods and results of this study in a paper published in Science Advances.