New contact lens lets humans see hidden infrared signals

People have long dreamed of seeing beyond the normal spectrum. Many rely on special devices, but a team of researchers has now rolled out a simpler way to detect hidden infrared signals in the environment.

Tian Xue, a neuroscientist at the University of Science and Technology of China, led a project that has introduced a non-powered contact lens with embedded nanomaterials.

The lens grants users the ability to perceive certain forms of infrared light, which starts around 700 nm and extends well beyond the familiar rainbow spectrum.

Researchers report that this approach opens the door to security and rescue applications, where flickers of invisible beams can become readable codes.

Contact lenses show infrared signals

These specialized lenses use nanoparticles that transform near-infrared light into frequencies that our eyes can recognize.

Users can see a flicker pattern coming from near-infrared beams in real time. They can even catch these signals with their eyes closed, because near-infrared wavelengths slip through the eyelids more easily than visible light.

“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,” said Xue.

In tests, researchers tried sending Morse code-like messages by blinking invisible light sources. Participants wearing the lens recognized the blinking pattern. 

Lens turns infrared into visible colors

The lens can be tuned to pick up different slices of the electromagnetic radiation range. Certain nanoparticles can transform multiple portions of near-infrared into different visible colors.

By modifying the nanomaterial setup, the wearer perceives distinct color shifts that correspond to separate parts of the infrared spectrum.

Researchers showed how wavelengths near 980 nm shift to a blue hue, while 808 nm signals turn to green. At the higher end, around 1,532 nm, some nanoparticles shift that energy to a reddish shade.

This strategy could also help people with color blind conditions detect wavelengths that ordinarily remain out of reach.

How these lenses help in security missions

The ability to detect infrared signals without bulky gear could change how soldiers operate in dark or obscured environments.

Instead of night vision goggles that rely on external power and give away a soldier’s position with reflections or heat, these lenses offer a more subtle and passive way to scan for threats or signals.

Surveillance teams could also use this tech to identify infrared-tagged objects or locations discreetly. Since the contact lenses are transparent and lightweight, they allow the user to operate hands-free while maintaining full awareness of both visible and infrared surroundings.

Applications and testing

Trials began with mice to make sure the lens itself was safe and functional. Results showed normal eye health in animals wearing the contact film.

Mice displayed behavioral signs of detecting near-infrared beams, choosing darker boxes when offered a space lit with infrared. Later, human volunteers tried the same concept, showing they could detect patterns of infrared light.

Scientists also built a set of wearable glasses that rely on the same nanotechnologies. The glasses improve image clarity and detail, thanks to a bit more distance between the nanomaterial and the retina.

This approach avoids scattering of converted light and might open up further uses in imaging or medical screenings.

Future uses of infrared signal lenses

In addition to rescue missions or security codes, this concept might help in poor lighting scenarios where standard vision struggles.

Infrared has long been used in night-vision devices, but these contact lenses do not need bulky external batteries or complex headsets. They draw power from the incoming infrared itself, thanks to the special upconversion process.

One focus is boosting sensitivity so these nanoparticles can detect weaker signals in dimmer settings. The ultimate goal is to fine-tune the resolution, allowing sharper images without losing the hands-free portability.

Designers hope to combine the ease of regular contact lenses with the extended range of advanced optical systems.

The lens could help in health checks

Researchers suggest that these lenses could eventually help doctors spot subtle heat changes linked to inflammation, poor blood flow, or even early-stage tumors.

Since near-infrared light interacts with tissue in ways visible light cannot, this opens up new possibilities for non-invasive screening during routine checkups or emergency care.

Dentists and surgeons might also benefit from real-time thermal feedback during procedures. Being able to “see” through tissue with color-coded signals could improve accuracy and reduce the need for heavy imaging machines in certain clinical settings.

Future of the infrared signal lens

A key step is confirming biocompatibility and stability for everyday use. The soft polymer base needs to stay comfortable on the eye while handling the embedded nanomaterials. Early results show no toxicity issues, but continued follow-up will confirm safety over longer periods.

Researchers believe that as the technology matures, it might pair with color enhancements for those missing certain photo pigments.

A future version of this lens could transform visible red light into green, widening the range that color-blind individuals can see. The team aims to refine production methods and push forward with clinical-grade testing.

The study is published in Cell.

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