Tetrachromacy is considered a rare condition in humans, which allows those with it to distinguish and see hundreds of shades of colors that, to the rest of us, simply look the same. But now researchers may have developed a special pair of glasses that will allow those without tetrachromacy to have a glimpse at what it is like to see the extra colors.
Reported in New Scientist, the special kit has been designed by a team at the University of Wisconsin-Madison, and could be used to aid those looking to counteract camouflage, or even to spot counterfeit bank notes. It can allow the wearer to distinguish between two shades of color that initially look identical but are actually subtlety different, known as metamers.
Humans usually have three cone cells in the eye that can perceive color – one that can detect short wavelengths of light, one medium, and one long – which correspond to the colors blue, green, and red, making most of us trichromats. Many creatures on the planet, tetrachromats, have four cells, which can allow some to see ultraviolet light.
But there are a number of people who have a rare condition in which they too have tetrachromacy. This allows them to see a vastly inflated number of colors that are “invisible” to the majority of people. It is thought that, because two of the cone cells are coded for on the X chromosome, women are more likely to have tetrachromacy then men, but exactly how many people affected is still unknown. The estimates range from 3 percent of women to as many as 50 percent.
The newly developed spectacles work by filtering out different parts of the blue light spectrum, meaning that each eye is seeing something slightly different when looking at blue objects. This made the ever-so-subtle differences in color between objects more pronounced, allowing the wearer to see the different metamers, and the results are impressive.
It means that different filters would have to be used to see metamers of other hues, such as green or red, but the researchers are currently working on these. Their work has not yet been published, but has been submitted for review.
It is thought that the new tech could then be used to see the small differences between colors used, for example, in camouflage, meaning that while under normal circumstances an object may blend in perfectly, under the filters they would obviously stand out.
