In Brief
Researchers have designed filters that allow the human eye to distinguish between color hues that are ordinarily too close to tell apart. These filters could be used to monitor the ripeness of fruits and vegetables or identify counterfeit money.

Tetrachromatic Shades

It can be impossible for humans to tell apart very similar colors. But, with a new pair of tetrachromatic glasses created by researchers at the University of Wisconsin-Madison, you can never again leave the house wearing two items of black clothing that don’t quite match.

These spectacles enhance the user’s existing color vision, affording them new power to discern more distinct shades. Once developed for practical applications, they could be used to spot camouflaged targets in the field or identify counterfeit money.

Color vision in humans relies on short, medium, and long types of cone cells reacting to blue, green, and red wavelengths of light, respectively. These three colors together make up the normal trichromatic vision of a human. Physicist Mikhail Kats was reviewing his knowledge of the eye as he prepared to teach a photonics class when he had an inspiration: could he trick the eye into seeing as though it had a fourth kind of cone cell, effectively giving people tetrachromatic vision?

New Tech Gives People Superhuman Vision
Credit: Steve Snodgrass / Flickr

Obviously, Kats decided the answer was “yes,” and the working glasses render blocks of color, called metamers, visibly distinct by helping the wearer’s eye perceive their different wavelengths of light. They tested the glasses by displaying metamers on a smartphone screen and computer. They looked identical without the glasses, but with them on it was easy to see the difference.

“They look exactly the same and you look through the spectacles and, holy crap, they’re two different things,” Kats said in an interview with New Scientist.

Exploration With Enhanced Senses

Kats’s team is working on filters to help distinguish metamers at the blue end of the visible spectrum, and will move on to greens next. After more hues can be distinguished with the filters, they can adapted for tasks like guarding fruits and vegetables against spoiling by watching their skins for changes. Tech like these tetrachromatic glasses equips us to see more of the universe around us, as part of a sensory enhancement movement.

In 2015, biohackers injected eyes with a chlorophyll analog to produce night vision. Bionic eyes are also on the way. New earbuds are giving troops superhuman hearing in combat — an edge that could save their lives.

Are you ready for your enhanced sensory equipment?