Researchers at the University of Science and Technology of China and the University of Massachusetts Medical School have successfully conducted procedures to allow mice to see infrared light with minimal adverse side effects. Infrared light has a longer wavelength than visible light and as a result, is not visible to mammals, except for bats. Using nanotechnology, researchers could provide the necessary eye conditions for the mice to see the infrared light.
To register light, the retina, rods, and cones of the eye, send electrical signals to the brain when they register and absorb photons of visible light. The longer wavelength of infrared cannot be incorporated in the same way and, therefore, humans cannot see it. The method of conversion consisted of inserting nanoparticles into the retina of the mice to convert the infrared light into green light of the visible light spectrum. The mice with nanoparticles injected showed unconscious signs of light recognition, such as pupil dilation, which is known to occur when visible light hits the eye. Mice without the nanoparticles did not experience such physical behavior and therefore did not experience any light recognition. The mice experienced cloudy corneas as a result of the injections, but these side effects disappeared within a week, and thus the scientists could consider these negative effects as negligible. The mice who only received buffer solutions also experienced these effects and so the researchers could deduce that the cloudy corneas were likely from the injections and not the nanoparticles.
For the medical profession, the success of the study provides the potential for the treatment of human red-color vision defects, as confirmed by the University of Science and Technology of China team co-leader Dr. Tian Xue. Other potential use of this technology lies in civilian encryption, security, and the military industry. The successful implementation of the light conversion could provide humans with so-called 'super-vision' where we could have night vision goggles without the disruption from ambient daylight, clunky equipment, or a need for a power supply.