I’m glad to see people are working on the contact-lens-as-display-device problem. Short of brain implants, I think this is the future of computer display. Read Rainbows End by Vernor Vinge for some possible applications of this type of technology, including some novel entertainment media.
The lenses will need to be powered somehow, and they will need a very up-to-the-microsecond notion of which way your eyes are pointing, but I reckon this should be feasable in ten to fifteen years.
A computer display that someone else might hack into and start strobing is the last thing I’ll be putting into my eyeballs. HUD Spectacles will be good enough, thank you.
HUD spectacles should come along first, I would think. (That’s how Charles Stross imagines the technology coming in his book Accelerando, incidentally.) There will be fewer problems and more space for batteries and motion sensing hardware. They will also be a good testing ground for software (including security) and user interface design.
I think contact lenses will be better in the long run because they’re more comfortable and convenient, but I’ll happily use HUD spectacles in the meantime.