Fig. 5: Correlation analysis between tear glucose (TG) and blood glucose (BG) for healthy and diabetic human participants.

a Photographs of a human participant wearing smart contact lens (SCL) and TG measurement with SCL. Scale bars, 2 cm. Here, the participant’s face was blocked using a black bar, except for the eyes, to infringe the portrait right. b Human study protocol for healthy and diabetic participants. c Representative real-time data of monitoring TG and BG level in a healthy participant after intake of a soft drink on day 1, 3, and 5. d Representative real-time data of monitoring TG and BG levels in a diabetic participant after intake of a nutrition beverage on day 1, 3, and 5. e Comparison of lag time in each human participant on day 1, 3, and 5. f Pearson’s correlation analysis between TG and BG levels of each representative healthy and diabetic participant. g Comprehensive Parkes Error Grid analysis of ten healthy participants and ten diabetic participants.