The visible spectrum of light that humans can detect is relatively limited. Ultraviolet light waves are too short and infrared waves are too long for our perception, although some animals have developed signal detection outside of humans' natural ability. But scientists in China have been experimenting with "upconversion nanoparticles" that can convert infrared light in the environment into colors that we can detect. After seeing success when injecting these nanoparticles into the retinas of mice, they looked for a non-invasive way to use this technology in humans. The answer is soft contact lenses embedded with these nanoparticles.
These lenses enable the wearer to see near-infrared signals. They can see these signals even with their eyes closed, because eyelids are only good at blocking visible light. The lenses do not detect far-infrared signals, which would be thermal vision, an ability some animals have already. Read about this ocular breakthrough at the Guardian. -via kottke
(Image credit: איתן טל)