New Contact Lenses Give Users Super-Vision to See Infrared Light—Even With Their Eyes Closed
Researchers have developed experimental contact lenses that use nanoparticles to convert the invisible wavelengths of near-infrared light into visible colors
/https://tf-cmsv2-smithsonianmag-media.s3.amazonaws.com/accounts/headshot/Margherita_Bassi.png)
Within the spectrum of electromagnetic radiation that reaches Earth, humans are only able to see a narrow range of wavelengths, called visible light. Now, however, a team of neuroscientists and materials scientists has created contact lenses that allow users to see the longer wavelengths of infrared light—and they’ll even work when people have their eyes closed.
“Over half of the solar radiation energy, existing as infrared light, remains imperceptible to humans,” Yuqian Ma, an ophthalmologist at the University of Science and Technology of China, tells the Guardian’s Ian Sample. But the new work marks a step toward changing that.
The team described their research in a study published last week in the journal Cell.
While night vision goggles, with which one can also see infrared light, have been around for a long time, these contact lenses boast a few key advancements. For one, they don’t need a power source, and they also enable users to see a number of different infrared wavelengths. Participants could also see visible light alongside the infrared, since the lenses are transparent, according to a statement from the journal.
“When wearing them, you still see everything normally,” lead author Gang Han, a nanoparticle researcher at the University of Massachusetts Chan Medical School, tells ABC News’ Karen Tachi Udoh. “The lenses simply add the ability to see infrared images on top of what we already normally see.”
Simply put, the team developed nanoparticles in the lenses that convert near-infrared light—wavelengths just a bit longer than what humans can perceive—into visible reds, greens and blues. In previous research, some of the same scientists gave mice infrared vision by injecting the nanoparticles directly into their eyes. Contact lenses are, clearly, a less invasive option.
/https://tf-cmsv2-smithsonianmag-media.s3.amazonaws.com/filer_public/9a/f4/9af45b4f-4950-4ff2-ab31-668575f5472f/infrared-contact-lense-2.jpg)
The researchers tested the new lenses on mice, too. While the animals couldn’t communicate to confirm whether the technology was working, their behaviors and physiology provided indirect clues to the team. The pupils of mice wearing contact lenses, for example, became smaller when exposed to infrared light, but mice without the lenses didn’t have that reaction. Brain imaging also revealed activity in the visual processing areas of the animals’ brains when the contact-wearing mice were exposed to infrared light.
In human trials, participants detected the presence and direction of flashing infrared light. Furthermore, the researchers “found that when the subject closes their eyes, they’re even better able to receive this flickering information, because near-infrared light penetrates the eyelid more effectively than visible light, so there is less interference from visible light,” Tian Xue, senior author of the study and a neuroscientist at the University of Science and Technology of China, says in the statement.
If you’re thinking of Superman’s iconic super-vision, it’s worth pointing out that the comic book hero can see X-rays, which are shorter than both infrared and visible light. On a more serious note, however, the practical applications of the new technology could be wide-ranging, from hands-free night vision for emergency responders and military personnel to detecting secret infrared messages.
The researchers suggest their approach might even help people with color blindness by converting the visible colors they can’t see into wavelengths they’re able to perceive.
However, the lenses aren’t quite there yet. For now, users can only see intense near-infrared light projected from an LED source, and they can’t pick up on small details or the much lower natural levels of infrared radiation.
“It’s an audacious paper, but using just the contact lens, you wouldn’t be able to read a book in the infrared or navigate down a dark road,” Mikhail Kats, an electrical and computer engineer at the University of Wisconsin-Madison who did not participate in the study, tells New Scientist’s Jeremy Hsu.
Moving forward, the researchers aim to continue developing the contact lenses and eventually make them more sensitive.
“This study opens the door to many exciting applications of wearable technology, potentially transforming how we see and interact with our environment, especially in challenging conditions,” Han tells ABC News.
