Tanya Weaver Fri 23 May 2025
Collected at: https://eandt.theiet.org/2025/05/23/nanoparticle-infused-contact-lenses-grant-humans-infrared-vision-even-eyes-closed
Researchers in China have developed contact lenses that overcome the limitations of human vision to open a “brand-new window onto the world”.
Infrared light is invisible to the human eye. A form of electromagnetic radiation, its wavelengths fall outside the eye’s visible range of 400-700 nanometres.
If humans want to see beyond this vision range – for instance, to be able to see in the dark – they use night-vision goggles or similar technology that can ‘see’ infrared wavelengths longer than 700 nanometres.
However, this may no longer need to be the case following a study by researchers at the University of Science and Technology of China (USTC) in Hefei, China.
The team infused contact lenses with nanoparticles that convert near-infrared light in the 800–1,600 nanometre range into the 400–700 nanometre range.
The new lenses offer multi-coloured infrared images that night-vision goggles, which operate on a monochrome green scale, typically do not. They also pick up intense infrared signals, such as those emitted by light-emitting diodes (LEDs).
To create the contact lenses, the research team added nanoparticles made of rare-earth metals, including ytterbium and erbium, to a soup of polymer building blocks to form the soft lenses.
Talking to Nature journal, Yuqian Ma, a neuroscientist at the USTC, revealed that the main challenge was to pack enough nanoparticles into the lenses to convert sufficient infrared light into detectable visible light, while not otherwise altering the lenses’ optical properties, including their transparency.
During tests, participants could see flickering infrared light from an LED well enough to both pick up Morse code signals and sense which direction the signals were coming from.
The lenses’ performance even improved when participants closed their eyes. This is because near-infrared light can easily penetrate the eyelids, whereas visible light does to a much lesser degree.
“Witnessing people wearing contact lenses and successfully seeing infrared flashes was undoubtedly an exhilarating moment,” Ma told Nature.
Further research will involve improving the technology’s sensitivity to enable the nanoparticles to convert light with higher efficiency.
Once the lenses have been optimised, the researchers foresee numerous uses for them – for instance, reading anti-counterfeit marks that emit infrared wavelengths, or even being worn by doctors during near-infrared fluorescence surgery to directly detect and remove cancerous lesions.
“We have overcome the physiological limitations of human vision, as if opening a brand-new window onto the world,” Ma told Nature.
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