With the evolution of technology, things that could be only imagined have been changing into reality. In past one could have only dreamed about their sunglasses turning darker or lighter with the touch of a button. But now, a range of colours and shading is possible with prototype eyewear made of electrochromic materials. Sunlight can vary significantly during outdoor activities such as motorcycling or skiing. Customary sunglass lenses, created with tinted glass or polycarbonate materials, have a fixed colour state. Lenses made with photochromic materials adjust to changing light, but rather slowly. Chemical engineer Chunye Xu and colleagues at the University of Washington have been working on "smart" sunglasses that can lighten or darken on command. The electrochromic polymer in Xu's prototype enables the lenses to lighten or darken in literally one second with just several milli watts of power. The button that engages the battery is located on the sidearm of the eyewear.

Xu said her group is also refining the circuitry of the sunglasses to make it more compact, and they are working with a company to examine the possibility of incorporating vision correction to make the smart glasses even smarter.
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