Contact lens tracks glucose in tears

years of research remain to see if such a system is medically viable

By Tracking Sugar In Tears, Contact Lens Offers Hope For Diabetics
January 16, 2014
http://www.npr.org/blogs/alltechconsidered/2014/01/16/263161180/smart-contact-lens-might-one-day-let-diabetics-check-blood-sugar

“At this point, we have functional prototypes,” said Brian Otis, the project lead at Google X. “We have integrated circuits that have been miniaturized to the point where they look like a piece of glitter integrated inside the soft contact lens material.”

The smart lens consists of this glitter-fleck-sized wireless computer chip as well as a microscopically small glucose sensor and an antenna thinner than a human hair. All of this is embedded between two layers of soft-contact lens material.

“We have a glucose sensor that has to be much more sensitive — because the concentration of glucose in tears is much lower than the concentration in blood. We’ve also created a way of tying all of these technologies together in a flexible platform,” Otis said — so flexible and soft that you could slip it over your eye.

This device is powered by harvesting radio waves from the air.
A minute capacitor harvests RF power and creates a little bit of static electric charge on the chip. The chip itself uses just one microwatt of power to operate. That’s one one-millionth of the amount of power required by your phone.