Comparing the Rise in Glucose Concentration in Blood, Aqueous and Interstitial Fluid During a Glucose Tolerance Test

PURPOSE: The purpose of the study was to determine if aqueous glucose levels rise in a comparable time frame to interstitial fluid and could therefore be suitable for a continuous glucose monitoring (CGM) site. METHODS: An intravenous glucose tolerance test was performed on five New Zealand white rabbits. Aqueous humor from the posterior and anterior chamber of the eye and venous blood were sampled for glucose concentration measurement. Glucose concentrations in the interstitial fluids were monitored using a CGM system. A compartment model was created to map the glucose response curves in each compartment. The delay in rising glucose concentrations between blood and interstitial fluid and aqueous humor in the posterior chamber and anterior chamber of the eye were analyzed. RESULTS: The results showed a statistically similar time lag and rate of change in glucose concentrations between blood and interstitial fluids or aqueous humor in either the posterior or anterior chamber. CONCLUSIONS: The results of this study add further support to the aqueous humor being used as an alternative CGM site. TRANSLATIONAL RELEVANCE: The study provides the basis for developing an intraocular continuous glucose sensor that can overcome limitations of current CGM systems.