c|net has tried out a laptop prototype from Tobii at the Consumer Electronics Show, that can be controlled with the eyes – and it works. The reporter, Rafe Needleman, was initially sceptical, as the eyes are only designed for input not output, but it turned out to be very fast and intuitive for him. It works by having the user press the Windows key, look at a tile and then release the key to activate the tile. The use of the keypress prevents one's eyes, which tend to dart around in normal use, from scrambling input to the laptop. As the user's gaze darts over the screen, the system gives an indication as to which tile is currently selected by the user's gaze to ensure accurate tile selection by the user. To achieve this feat, the modified laptop uses two infra red emitters and two special IR cameras along the Windows 8 customer preview released a while back. They use "the reflective point of the retina, plus the glint off the cornea" Rafe was told. From this, the computer builds a 3D model of the user's gaze to work out where they are looking on the screen. Rafe concluded, "I did not expect to like it, but I did. It is intuitive to use, and very fast. Tobii has done a good job of making your glances into workable input signals."