Wearers of ‘super-vision’ contact lenses can see even in the dark

Scientists have developed innovative night-vision contact lenses that could give users what they describe as “super-vision.” These cutting-edge lenses use unique nanoparticles that absorb low-frequency light and re-emit it as visible light in order to detect infrared wavelengths, which are typically invisible to the human eye. In contrast to traditional night-vision goggles, the lenses operate without a power supply. The journal Cell Press published a report on the discovery on May 22.

This breakthrough raises the possibility of wearing, non-invasive gadgets that improve human eyesight, according to senior author Tian Xue, a neuroscientist at the University of Science and Technology of China. He noted that such technology could be used in security, emergency response, encrypted communication, or anti-counterfeiting, by utilizing flickering infrared signals.

Image-intensifier tubes are used in traditional night vision devices, which were first utilized during World War II, to transform visible and near-infrared light into electrons. These electrons are then projected onto a screen that glows green. However, these systems rely on external power sources, making them bulky, and they struggle to detect the full range of infrared light, particularly longer wavelengths.

In contrast, the new contact lenses contain nanoparticles made from sodium gadolinium fluoride doped with luminescent elements like ytterbium, erbium, and gold. These are embedded within soft, non-toxic polymers commonly used for contact lenses. The particles are capable of converting near-infrared wavelengths between 800 and 1,600 nanometers into visible light within the 380 to 750 nanometer range.

Testing began with mice, which naturally prefer darkness to avoid predators. Infrared-light-illuminated boxes were avoided by mice with the new lenses, but not by mice without them. Their pupils also contracted when exposed to infrared light, and brain scans indicated activity in areas linked to visual processing. When tested on humans, wearers could detect flickering infrared light and even determine its direction. Interestingly, closing their eyes enhanced this perception, as near-infrared light penetrates eyelids more effectively than visible light, reducing visual interference.

Additionally, scientists tested with altered nanoparticles that could potentially aid those who are color blind by mapping various infrared spectrum regions to visible hues. By transforming red light into green, for instance, this approach could allow color-blind users to perceive hues they normally miss. Although promising, the lenses currently only respond to bright LED infrared sources. To make them more practical, scientists aim to improve their sensitivity and overcome limitations in detecting fine details due to their close proximity to the retina. As a solution, they are also developing wearable glasses for high-resolution viewing.