A soft hydrogel contact lens with an encapsulated sensor for tear glucose monitoring

We report a hydrogel-based contact lens with an encapsulated glucose sensor. The sensor is fabricated on a flexible transparent parylene film. The parylene-based sensor is then encased inside a soft contact lens made of poly(hydroxyethyl methacrylate) (polyHEMA) hydrogel. We test the glucose sensor with different concentrations of glucose and interfering chemicals found in tear film, such as ascorbic acid. The rapid response, good linearity and repeatability demonstrate the basic functionality of this soft contact lens.