"Smart contact lens." Get used to that term, even if it makes you cringe - a new patent from Google indicates that at least someone at Mountain View thinks it's a potentially viable idea. Patent Bolt reports on a Google application to the USPTO for "multi-sensor contact lenses," intended primarily as a method for blinking input or input augmentation for wearable devices, or just electronics in general. (Note: this shouldn't be confused with Google's other contact lenses, announced in January as a medical diagnostic device for diabetics.)
The basic idea is that a number of sensors embedded into a contact lens could be used to detect blinks with incredible accuracy.