Lenses detecting invisible infrared light developed by Chinese scientists

Scientists in China have developed contact lenses that allow people to see near-infrared light, potentially paving the way for superhuman vision in everyday life.

The soft lenses, described in the journal Cell, use upconversion nanoparticles to absorb invisible infrared radiation and convert it into visible red, green or blue light. When worn, users can see infrared signals while still perceiving the full range of normal visible colours — no power source required.

Unlike night vision goggles, the lenses are transparent and wearable in daylight. Researchers say the technology could one day lead to advanced glasses, contacts or wearables capable of enhancing human vision well beyond natural limits.

Prof Tian Xue, a neuroscientist at the University of Science and Technology of China, called the project a step towards “super-vision”. He said the approach could also be adapted to assist people with colour blindness by converting unseen wavelengths into detectable hues.

Dr Yuqian Ma, another member of the team, noted that more than half of the Sun’s energy arrives as infrared radiation — most of it invisible to humans.

“Over half of the solar radiation energy, existing as infrared light, remains imperceptible to humans,” said Ma. “Our work brings us closer to perceiving what has always been hidden.”

Previous studies by the same group gave mice near-infrared vision using injections of nanoparticles behind the retina. But recognising that such methods are unlikely to gain human approval, the team explored a non-invasive route with wearable lenses.

In tests, participants wearing the lenses could see Morse code-style signals flashed by infrared LEDs. They could also detect the direction of an infrared light source — even with eyes closed, as the eyelids block visible light more than infrared.

The current version of the lenses does not enable users to see body heat or thermal radiation, as it lacks sensitivity to far-infrared. But scientists are working on improving their efficiency, with hopes of enhancing real-world infrared vision in the future.

“If materials scientists can develop upconversion nanoparticles with higher efficiency, it may become possible to see surrounding infrared light using contact lenses,” said Xue.

Even in their early form, the lenses could be used to reveal secret messages or for augmented reality applications — enabling users to access visual information invisible to others.