Researchers have made a groundbreaking discovery by stimulating human retinas with a precise laser setup, allowing five participants to see a color beyond their typical visual range. This saturated bluish-green hue was previously unknown to the human eye.
The retina contains three types of cone cells, each sensitive to different wavelengths of light: S cones for blue, M cones for green, and L cones for red. These signals are combined in the brain to create full-color vision. However, these cone cells overlap in their response ranges, meaning no single wavelength can exclusively activate one type of cone cell.
This limit was discovered by Ren Ng, a professor at the University of California, Berkeley, who explained that any light activating M cones will also stimulate either S or L cones. This limitation means scientists have been unable to observe colors outside the familiar spectrum of 10 million hues. The new discovery paves the way for further exploration into the complexities of human vision and color perception.
Source: https://www.scientificamerican.com/article/researchers-discover-new-color-thats-impossible-to-see-without-lasering-your