New contact lenses let humans see in the dark — Even with eyes closed

Scientists have developed futuristic contact lenses that enable humans to see in the dark using infrared light, without the need for bulky goggles or external power sources. The breakthrough, published in Cell on May 22, uses

nanoparticle-infused lenses

to convert invisible near-infrared wavelengths into visible images, offering the potential for “super-vision” in rescue operations, security, and medical fields.“These lenses could revolutionise wearable vision technology,” said senior author Tian Xue of the

University of Science and Technology of China

, in a statement quoted by Live Science. “Our research opens up the potential for non-invasive wearable devices to give people

super-vision

.”Unlike traditional night-vision goggles, which rely on image-intensifier tubes and require battery power, the new lenses absorb low-frequency infrared light and re-emit it within the visible spectrum.

The nanoparticles, made from sodium gadolinium fluoride and embedded with luminescent ytterbium, erbium, and gold, are housed inside soft, non-toxic polymers typically used in everyday contact lenses.As per The Independent, these lenses detect infrared light between 800 and 1,600 nanometers, just beyond the natural perception range of the human eye and translate it into visible wavelengths ranging from 380 to 750 nanometers.Initial testing in mice showed promising results. According to Live Science, rodents wearing the lenses consistently chose to avoid infrared-illuminated boxes, while those without the lenses displayed no such preference. Brain scans confirmed that visual processing centres in the mice responded to infrared stimuli, and their pupils constricted in the presence of such light.The lenses were then tested on human volunteers. Users could perceive flashing Morse code-like infrared signals and detect their direction. “It’s totally clear cut: without the contact lenses, the subject cannot see anything, but when they put them on, they can clearly see the flickering of the infrared light,” Xue was quoted by the Live Science. Interestingly, vision improved with eyes closed, due to infrared light’s ability to penetrate eyelids more effectively than visible light.As per ABC News, Gang Han, a nanoparticle expert from UMass Chan Medical School and co-author of the study, said the lenses also enhance how people perceive colour. “What’s special about our contact lenses is that they let you see infrared light in colour, like red, green and blue — so you can tell different things apart more easily,” he said.Scientists have also experimented with tuning the lenses to help people with colour blindness by mapping parts of the near-infrared spectrum to visible hues like green or red. “By converting red visible light into something like green visible light, this technology could make the invisible visible for colour blind people,” Xue noted.However, limitations remain. The current lenses can only detect intense infrared light from LED sources. Researchers aim to boost sensitivity to recognise fainter sources and improve resolution by pairing the lenses with wearable glasses.Looking ahead, Han believes this technology could be vital in search-and-rescue missions, military operations, or even surgery. “This study opens the door to many exciting applications of wearable technology,” he said, “potentially transforming how we see and interact with our environment, especially in challenging conditions.”