FROM THE house of Nikon have come electric spectacles that are battery-operated and change 0 from dark to light and back again at the touch of a button in less than 10 seconds. In contrast, the better known photochromatic lenses can take up to an hour to turn clear on coming indoors.
The batteries are hidden next to the hinges of the spectacles beneath switches. The switch on the right is used to turn the lenses dark, while that on the left clears them.
However, there are drawbacks. For one, the spectacles cost a prohibitive $416 for a pair. For another, it is available only in three styles, and that too for men. The third, and perhaps the greatest, shortcoming is that the spectacles are available only with non-prescription lenses, which can be mass-produced; prescription lenses have to be made to order.