The age of the bifocal is over: a firm called PixelOptics has designed a pair of glasses for which the focal length can be adjusted at the touch of a button. How long until they can do so much more?

These glasses — in which a layer liquid crystal is placed inside the lens and, when activated by an electric current, it alters it's refractive properties. According to Peter Zieman, director of European sales for PixelOptics:

"Liquid crystals can change their refractive index when an electrical charge is put through them, so wearers can switch between distance and reading in the time it takes to blink.... Putting in the kind of motion sensors that are used in the iPhone also allows the glasses to sense when someone is reading a book or a newspaper and so change the focal distance of the lenses automatically."

Now, if they build a pair with an onboard digital camera and wifi, we're in business.