The lens consists of a wireless chip and a miniaturized glucose sensor. A tiny pinhole in the lens allows for tear fluid to seep into the sensor to measure blood sugar levels. Both of the sensors are embedded between two soft layers of lens material. The electronics lie outside of both the pupil and the iris so there is no damage to the eye. There is a wireless antenna inside of the contact that is thinner than a human's hair, which will act as a controller to communicate information to the wireless device. The controller will gather, read, and analyze data that will be sent to the external device via the antenna. Power will be drawn from the device which will communicate data via the wireless technologyRFID. Plans to add small LED lights that could warn the wearer by lighting up when the glucose levels have crossed above or below certain thresholds have been mentioned to be under consideration. The performance of the contact lenses in windy environments and teary eyes is unknown. The prototypes being tested can generate a reading once per second.
Announcements
On 16 January 2014 Google announced that, for the past18 months, they had been working on a contact lens that could help people with diabetes by making it continually check their glucose levels. The idea was originally funded by the National Science Foundation and was first brought to Microsoft. The product was created by Brian Otis and Babak Parviz who were both members of the electrical engineering faculty at the University of Washington prior to working in Google's secret lab, Google X|Google. Google noted in their official announcement that scientists have long looked into how certain body fluids can help track glucose levels easier, but as tears are hard to collect and study, using them was never really an option. They also mentioned that the project is currently being discussed with the FDA while still noting that there is a lot more work left to do before the product can be released for general usage, which is said to happen in five years at best, and that they are looking for partners who would use the technology for the lens by developing apps that would make the measurements available to the wearers and their respective doctors. The partners would also be expected to use this research and technology to develop advanced medical and vision devices for future generations. On July 15, 2014, Google announced a partnership with Novartis' Alcon unit to develop the glucose-sensing smart contact lens. On November 16, 2018, Verily announced it has discontinued the project because of the lack of correlation between tear glucose and blood glucose.
Response
Endocrinologist Dr. Larry Levin commented the benefits of being able to offer his patients a pain-free alternative to either pricking their fingers or using a continuous glucose monitor. However, experts in the field have cast doubt on the ability of the amount of glucose in tears to correlate strongly with blood glucose of the user. Many reported studies show, at best, a weak correlation that would not meet accuracy requirements for glucose monitoring.
