As is the case with the mouse, joystick, touch type devices, voice recognition and so on...this eye thing will have it's place - that is to say it will suit some applications and not others. And, part of it's success would of course depend on configurability, integratability and so on.
Future trend predictions can be hard...but I don't think it will be "massively popular".
I'm with Gertsy on this one - for challenged people this most certainly will have it's place. It would probably also be useful in applications where hand movements are used for other functions - and so a "normal" device can't be used.
