According to The Times of London on December 12, eyeglass wearers could avoid the problem of eyeglasses fogging up on cold days thanks to a gold "nano-coating" that heats up the lenses.

  The technique relies on a layer of ultra-thin gold particles, which are applied to the lenses of the eye, the report said. The transparent coating converts sunlight into heat, preventing moisture from forming in the lens.

  When water vapor in humid air cools quickly on contact with cold glass surfaces, the glasses fog up. Tiny droplets of water, or condensation, form on the lenses.

  Tiny droplets of water scatter light in many directions, making it difficult to see what's in front of you, in much the same way that fog affects vision.

  According to the paper published in the British journal Nature Nanotechnology, the new coating uses solar energy to raise the temperature of the lens, preventing moisture from condensing and thus avoiding fog, at least during the day. The electric heating element that defogs the rear windscreen of a car is also based on this principle.

  The new coating works because it selectively absorbs only part of the energy released by the sun. Half of the sun's energy is in the infrared spectrum, the other half is in the visible and ultraviolet radiation spectra.

  "Our coating absorbs a large proportion of the infrared radiation, which heats it up - by up to eight degrees Celsius," says Ivan ASHLEY of ETH Zurich.