Researchers at the University of Akron in Ohio are developing contact lenses that may make those finger sticks a thing of the past. Blood glucose isn’t the only thing to vary during the day as glucose concentrations change. Along with blood also urine and tear glucose levels change to mimic or match that of the blood. Dr. Jun Hu has coated a contact lens with a chemical that reacts to glucose in tears similar to pH paper changes. The coatings causes the lens to change color. Patients wear the color changing lens in only one eye.
Measurements taken with a cell phone app allows the color difference between the two eyes to produce a tear (and hence blood) glucose calibration. No special light is needed; all patients need is a smartphone with a camera.
Patients vision is not affected by the tinting process. These lenses are in use but only in the testing phases. Expect to see them commercially in 3-5 years.