Seeing infrared: contact lenses that grant 'super-vision'

Summary

Researchers have given people a taste of superhuman vision after creating contact lenses that allow them to see infrared light, a band of the electromagnetic spectrum that is invisible to the naked eye.Unlike night vision goggles, the contact lenses need no power source, and because they are transparent, wearers can see infrared and all the normal visible colours of light at the same time.Prof Tian Xue, a neuroscientist at the University of Science and Technology of China, said the work paved the way for a range of contact lenses, glasses and other wearable devices that give people “super-vision”. The technology could also help people with colour blindness, he added.The lenses are the latest breakthrough driven by the team’s desire to extend human vision beyond its natural, narrow range. The wavelengths of light that humans can see make up less than one hundredth of a per cent of the electromagnetic spectrum.Dr Yuqian Ma, a researcher on the project, said: “Over half of the solar radiation energy, existing as infrared light, remains imperceptible to humans.”The rainbow of colours visible to humans spans wavelengths from 400 to 700 nanometres (a nanometre is a millionth of a millimetre). But many other animals sense the world differently. Birds, bees, reindeer and mice can see ultraviolet light, wavelengths too short for humans to perceive. Meanwhile, some snakes and vampire bats have organs that detect far-infrared, or thermal radiation, which helps them hunt for prey.To extend humans’ range of vision and enhance our experience of the world, the scientists developed what are called upconversion nanoparticles. The particles absorb infrared light and re-emit it as visible light. For the study, the scientists chose particles that absorb near-infrared light, comprising wavelengths that are just too long for humans to perceive, and converted it into visible red, green or blue light.In previous work, the research team gave mice near-infrared vision by injecting upconversi...