A team of scientists in the United States claims to have experienced a previously unseen color through an experimental procedure involving laser pulses fired into their eyes. This innovative experiment aimed to push the boundaries of human perception by stimulating individual cells in the retina, a method that allowed participants to perceive a new hue.
The color, described by five participants as resembling a blue-green shade, was named “olo.” Despite its apparent similarity to existing colors, the researchers emphasize that the richness of the experience was unparalleled. The experiment was led by Ren Ng, an electrical engineer at the University of California, Berkeley, who noted that the color was “incredibly saturated” and unlike anything perceived before.
To illustrate the color, the researchers shared an image of a turquoise square, although they stressed that such representations fall short of capturing the true essence of olo, which can only be experienced through specific laser manipulation of the retina. Vision scientist Austin Roorda highlighted that the color visible in traditional media is merely a version of olo, lacking the vibrancy encountered through the experiment.
Human color perception operates through light-sensitive cells called cones in the retina, which include three types sensitive to long, medium, and short wavelengths of light. Natural light comprises a mixture of these wavelengths, leading to the perception of various colors. The Berkeley team sought to isolate the medium (M) cones, which cannot be exclusively stimulated by natural light, to create this new visual experience.
The researchers mapped the positions of M cones on a participant’s retina and used a laser to precisely target and stimulate these cells. This process resulted in a color patch within the participant’s field of vision, achieving a saturation that natural light cannot replicate. The name “olo” is derived from the binary representation 010, indicating the activation of only the M cones.
However, some experts remain skeptical. John Barbur, a vision scientist at City St George’s, University of London, argues that the color is not genuinely new, but rather a more saturated green achievable under specific conditions in individuals with normal red-green chromatic mechanisms.
Despite differing opinions, the researchers believe their tool, named Oz vision after the Emerald City in the L Frank Baum books, could advance understanding of how the brain constructs visual perceptions. This method may also have potential applications in studying color blindness or vision-affecting diseases like retinitis pigmentosa.
While the experience of olo remains confined to the laboratory, the researchers acknowledge that it will not be available on smartphones or VR headsets anytime soon. For now, this groundbreaking exploration into the limits of human vision represents a significant step in basic science.