The World Health Organization estimates that glaucoma is the second leading cause of blindness worldwide. And though the first leading cause of blindness - cataracts - can be treated with surgery, the blindness caused by glaucoma can't be permanently cured. That's why Tingrui Pan and Hailin Cong, researchers at UC Davis, have designed a contact lens that keeps tabs on the disease all by itself. And they're working up to one that dispenses medication automatically, too.Their "smart" lenses are fitted with an organic polymer called polydimethylsiloxane (PDMS), which is commonly used in biological applications. Since glaucoma develops as a result of raised pressure inside the eye, the goal of the lenses is to detect that intraocular pressure and mark warning signs. Up until now, though, PDMS hasn't been used as a sensor of anything, since the creation of sensor circuits requires conductivity — and PDMS doesn't have that. Pan and Cong, however, found a way to make conductive composites of PDMS and apply them to contact lenses, and thus a pressure-sensing fashion statement was born. With these smart lenses, patients won't have to rely on visits to the doctor to check their intraocular pressure. The sensors on top of their eyes will be doing it all by themselves, and sending the data to a computer to boot.
"It's very different from situations like cardiac disease or diabetes, where patients can wear devices that measure heart rate or blood pressure 24 hours a day for a week or more to get a better idea of what's going on," says James Brandt, a professor of ophthalmology at UC Davis and Pan's collaborator. "We don't have that for glaucoma, and that's one of the biggest clinical frustrations we have."Pan and Cong will be teaming up with Brandt to begin trials of the smart contact lenses in humans. This isn't the first contact lens with a circuit — a University of Washington team managed to embed LEDs into a lens in pursuit of superhuman vision — but this is the first with direct applications toward treating a disease. No word yet on whether that PDMS composite is really, really annoying to try and see through, however. Pressure Sensing Contact Lenses May Provide Continuous Glaucoma Monitoring [medGadget] Smart Contact Lenses [UC Davis] Pressure-Sensing Contact Lenses [Technology Review] Photopatternable Conductive PDMS Materials for Microfabrication [Advanced Functional Materials] Image from UC Davis.