Different creatures within the animal kingdom have varying degrees of vision and color perception. Whereas vampire bats are likely colorblind, there are some snakes with infrared senses, mice with sensitivity to UV light, and birds who have tetrachromatic vision (meaning they see the world through four color cones), which differs from humans who have just three color cones and can perceive only a limited range of colors. In fact, the wavelengths of light that humans can see comprise less than one hundredth of a percent of the total electromagnetic spectrum. A team of researchers is now looking to change that—and they’ve found early success in the shape of a contact lens.
As outlined in a study recently published in Cell, these nanotechnology lenses allow humans to detect infrared light, which would otherwise be invisible to the naked eye. To accomplish this, scientists developed “upconversion nanoparticles” that absorb infrared light and convert it into visible light in shades of red, green, and blue. The specialized lenses were later coated with those very nanoparticles, effectively expanding the field of human vision. When worn, the lenses permitted study participants to identify flashes of infrared light, basic shapes and patterns, and colors within the infrared range. Notably, participants could even perceive infrared images through closed eyes, given that infrared light can pass easily through eyelids.
“When wearing [the lenses], you still see everything normally,” Gang Han, the study’s lead author and a nanoparticle researcher at UMass Chan Medical School, told ABC News. “The lenses simply add the ability to see infrared images on top of what we already normally see.”
Night-vision goggles may have similar capabilities, but they’re far more unwieldy, often require a power source, and generate images that are green or black-and-white.
“What’s special about our contact lenses is that they let you see infrared light in color—like red, green, and blue—so you can tell different things apart more easily,” Han adds.
The contact lenses were developed following previous research conducted with mice. In these earlier experiments, researchers managed to give mice near-infrared vision by directly injecting the upconversion nanoparticles under their retinas—an invasive method that the team recognized wouldn’t necessarily be ideal for humans. These contact lenses, however, can serve several purposes within our society, according to Han.
“Our lenses help rescuers see clearly and navigate safely in dangerous environments like fires or dense fog,” he explains. “This study opens the door to many exciting applications.”
The lenses could also be beneficial for those with color blindness, helping convert wavelengths they can’t see into those they can. Tian Xue, a neuroscientist at the University of Science and Technology of China, also references incorporating infrared into secret messages, visible only to those with the special contact lenses.
To learn more, read the full study in Cell.
Scientists have developed contact lenses that offer humans “super-vision”—or the ability to perceive infrared light, which is otherwise invisible to us.
Sources: Near-infrared spatiotemporal color vision in humans enabled by upconversion contact lenses; Nanotech contact lenses give humans ‘super vision,’ even in total darkness with eyes shut: Study; Seeing infrared: scientists create contact lenses that grant ‘super-vision’
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