A team in China has woven tiny, light-converting particles into soft contact lenses, granting wearers the power to perceive infrared light both in the dark and, surprisingly, with their eyes closed.
The “seeing with your eyes shut” part arises because near-infrared light penetrates the eyelid more effectively than visible light. That futuristic enhancement doesn’t even need a source of power to operate.
The science behind the magic relies on upconverting nanoparticles — an elegant bit of physics that stretches the limits of human vision. Under normal conditions, the human eye can detect electromagnetic radiation in the range of roughly 400 to 700 nanometers, encompassing all the colors of visible light from violet to red. Anything beyond that range, such as ultraviolet or infrared light, is invisible to us because our photoreceptors simply aren’t built to respond to it.
But these newly engineered contact lenses change the rules. The upconverting nanoparticles absorb multiple low-energy infrared photons, each invisible on its own, and combine their energy to emit a single, higher-energy photon in the visible spectrum. These particles absorb glimmers of low-energy infrared light (800–1,600 nm) and emit single bursts of visible light (400–700 nm), right onto your cornea.
It’s a bit similar to how night vision goggles work, but with a key twist. Night vision goggles — first developed during World War II — typically use an image intensifier tube. This entire process requires electricity, bulky hardware, and a lens system. It amplifies light but doesn’t truly shift the light’s wavelength. The new lens is more efficient and doesn’t need a power supply.
“Our research opens up the potential for non-invasive wearable devices to give people super-vision,” says senior author Tian Xue, a neuroscientist at the University of Science and Technology of China. “There are many potential applications right away for this material. For example, flickering infrared light could be used to transmit information in security, rescue, encryption or anti-counterfeiting settings.”
From mice to humans
The team had earlier demonstrated this concept in mice by injecting the particles directly into their eyes. This was a powerful proof of concept, but not exactly a comfortable upgrade for humans. The new lenses sidestep the syringe entirely.
First came tests in mice. Their pupils shrank in response to infrared stimuli, and brain scans showed that visual areas lit up just as they would with normal light. Researchers subjected the mice to a classic “light or no light” maze. The animals preferred hiding in dark boxes, as expected. But when infrared light lit one of the boxes, only lens-wearing mice avoided it — evidence that they could now see wavelengths beyond their natural reach.
Then came humans. Participants wearing the lenses were able to detect Morse-code-like infrared flashes and determine the direction they were coming from. The lenses even worked with closed eyes — an eerie, almost supernatural ability that would presumably make it very difficult to sleep at night.
The researchers also wanted to see if they could get people to see colors in the dark. They designed the lenses to distinguish between different parts of the infrared spectrum by color. For example, 980 nm infrared became blue, 808 nm turned red, and 1532 nm showed up as green. This approach could help users read invisible codes or even help people with color blindness. Essentially, it could get people to see colors they can’t naturally see.
Still, there are limits. The lenses currently only detect powerful, narrow-band infrared sources, like LEDs. That’s why participants couldn’t read a book or recognize facial features in low-light rooms. The lenses scatter light too much to provide detail.
The eyes of tomorrow
The idea of getting people to see in the dark is an audacious one. For decades, night vision has been used to give soldiers a spectral edge. Today, it guides drones, satellites, and telescopes.
Now, researchers want to bring it into everyday human perception; and there are some very exciting applications.
Imagine firefighters navigating smoke-filled buildings without bulky masks. Imagine surgeons seeing heat differentials in living tissue, or hikers spotting lost trail companions in the dark. We might even see civilians with color blindness gaining a fuller spectrum of sight. All of the things we can achieve with spectral cameras (which are already pretty amazing), we could soon do with our naked eyes (and contact lenses). The sci-fi eyes of the future may soon be coming.
But to get there, scientists must solve major engineering puzzles. Enhancing spatial resolution, boosting sensitivity to lower light levels, and ensuring long-term safety of nanomaterials are just a few. If successful, though, the rewards could be transformative.
The study was published in Cell.
