A lot of people have tried, without much luck. Verily (part of Google/Alphabet) had a joint project with Novartis to build contact lens that sensed glucose in

A lot of people have tried, without much luck. Verily (part of Google/Alphabet) had a joint project with Novartis to build contact lens that sensed glucose in tears, but it didn't pan out. An analytical chemist has assembled a compendium of approaches that haven't panned out here: http://www.mendosa.com/noninvasive_glucose.pdf http://www.mendosa.com/noninvasive_glucose.pdf