There has been a fair amount of research and (seeming) success in this area: https://www.medicaldesignandoutsourcing.com/mit-researchers-develop-light-based-dev

There has been a fair amount of research and (seeming) success in this area: https://www.medicaldesignandoutsourcing.com/mit-researchers-develop-light-based-device-to-measure-blood-glucose/ https://www.medicaldesignandoutsourcing.com/mit-researchers-... Not sure how close it is to being out of the lab but it definitely seems doable.