We're fascinated by the idea of bringing medical-grade devices to market - and it is happening - but the long promise of a contact lens capable of tracking glucose levels is yet to be fulfilled, despite Google and others beavering away.
Now, a crack squad of engineers at Oregon State University reckon they're almost there. They've been working on a project that uses transparent transistors built from a compound found in many gadget screens, known as IGZO (indium gallium zinc oxide), mixed with an enzyme that breaks down glucose. When glucose is added, it leads to a reaction that causes a change in the electrical current through the contact lens.
"We believe that our approach will have the sensitivity that is required to accurately predict blood glucose levels using tear fluid," Dr Gregory Herman, who worked on the project, told Wareable. Interestingly, Herman and two colleagues actually invented the IGZO compound a few years ago, but at the time it wasn't intended for something like this.
There are a lot of people in the medical field who have so far doubted the ability of a 'smart' contact lens to match the accuracy of glucose detection as the pin-prick method or other medical-grade trackers. However, with this new approach, Dr Herman and the team may have cracked it. "We have already demonstrated that we can detect down to 10 micromolar concentrations," Dr Herman told us. "Typical glucose levels in tears are hundreds of micromolar." He added that the plan is to miniaturise the device to further increase sensitivity.
Not only would a glucose-tracking contact lens help diabetes sufferers avoid related health problems, but it would make the process much more comfortable than existing methods. It also has a good chance of being totally transparent, while Google's proposed lens would have a small chip and sensors built in.
Excitingly, there are other potential applications beyond glucose too. "We recently demonstrated we can measure uric acid concentrations, which is a biomarker for renal disease," said Dr Herman.
"We believe we can expand to monitoring for many more diseases, especially since we can integrate these transparent sensors over the entire contact lens. Ultimately, we can have a few to thousands of sensors, each for specific diseases, including early cancer detection and biomarkers for cardiac disease."