The power range of the lenses is + 6 to -6 Diopters, and once the lenses are set, you take the vials off the arms of the glasses and store them for safe keeping.

In 2008, Intel showed off its take on wireless power solutions, while at the Consumer Electronics show in Las Vegas earlier this year, several manufacturers unveiled wire-free charging devices.

If solar power is ever going to take off-and the world needs it to-photovoltaic cells will have to become a whole lot cheaper to produce.