Noncontact Optical Measurement of Aqueous Humor Glucose Levels and Correlation with Serum Glucose Levels in Rabbit

Abstract

The noninvasive measurement of serum glucose levels has been investigated for the monitoring of blood sugar control in diabetes. In our study, we aimed to develop a novel noncontact glucometer (NCGM) utilizing an optical approach to measure the intraocular aqueous humor glucose levels in the anterior chamber of rabbit eyes. The NCGM consists of a hybrid optical system that simultaneously measures near-infrared absorption and the polarized rotatory distribution of glucose molecules in the aqueous humor. In vitro optical measurements demonstrated that NCGM measurements had high precision and repeatability for different glucose levels, including 50 mg/dL (14.36%), 100 mg/dL (−4.05%), 200 mg/dL (−5.99%), 300 mg/dL (4.86%), 400 mg/dL (−2.84%), 500 mg/dL (−0.11%), and 600 mg/dL (4.48%). In the rabbit experiments, we found a high correlation between aqueous glucose levels and serum glucose levels, with a mean difference of 8 mg/dL. According to the testing results, the in vivo NCGM measurement of aqueous humor glucose levels also displayed a high correlation with serum glucose levels, with a mean difference of 29.2 mg/dL. In conclusion, aqueous humor glucose levels were accurately measured using the NCGM, and the results correlated with serum glucose levels.

Noncontact optical device for measuring blood glucose in aqueous humor: a pilot clinical study investigating correlation with blood glucose levels

“…Given this consistent ratio between aqueous humor and blood glucose, we can utilize the NCGM to determine serum glucose levels in humans. Our laboratory has previously demonstrated that NCGM readings show a strong correlation with aqueous humor and blood glucose levels in rabbits, with an average aqueous humor to blood glucose ratio of 0.82 before the glucose challenge 24 . In the current study with human participants, the NCGM measurements demonstrated strong predictive accuracy for blood glucose levels (ICC>0.9 with P<0.001).…”

“…Our laboratory has previously demonstrated that NCGM readings show a strong correlation with aqueous humor and blood glucose levels in rabbits, with an average aqueous humor to blood glucose ratio of 0.82 before the glucose challenge. 24 In the current study with human participants, the NCGM measurements demonstrated strong predictive accuracy for blood glucose levels ( with ). The correlation between NCGM and SMGB at various time points was also high ( with ).…”

“…The noncontact glucometer (NCGM) uses concurrent measurements of the NIR absorption and polarized rotatory distribution of glucose molecules in the eye’s aqueous humor to determine blood glucose levels. The accuracy of this device has been previously demonstrated in animal experiments and published in the literature 24 . In this study, the NCGM’s measurements were validated in human subjects by correlating them with aqueous humor and blood glucose levels and SMBG readings.…”

“…The general time frame to obtain a measurement is between 30 and 60 s. Further details about the device and glucose calculation can be found in the previously published literature 24 and the US patents (Nos. US20160299058A1 and US9662004B2).…”

“…The accuracy of this device has been previously demonstrated in animal experiments and published in the literature. 24 In this study, the NCGM’s measurements were validated in human subjects by correlating them with aqueous humor and blood glucose levels and SMBG readings.…”