Texas A&M University College Station United States
Using optical polarimetry for probing aqueous humor glucose concentrations has the potential for ascertaining blood glucose noninvasively. One major limiting factor for the realization of polarimetry is time-varying corneal birefringence due to motion artifact. To enhance the speed of the polarimetry system and provide real time closed-loop feedback at two wavelengths that can help overcome the time-varying birefringence, a dual-modulation system was designed, built and tested. This new system utilized laser intensity and polarization modulation to increase the frequency. This configuration also reduced the system complexity by reducing the number of detectors from two to one. In this study, the high speed technique was developed and in vitro phantom studies were performed with and without motion. The glucose concentration ranged of 0-600 mgdl and the glucose measurements demonstrated the sensitivity and accuracy of the system to within 10 mgdl without motion and within 14 mgdl with motion. Our feedback control systems took less than 10 ms to reach stabilization, which is adequately fast to eliminate the effect of time-varying birefringence. The results indicate that this new optical polarimetric approach has improved the speed and reduced the complexity, showing the potential for it to be used for non-invasive glucose measurements.
OSTP Journal Article
Journal of Biomedical Optics, 21, 8, 01 Jan 0001, 01 Jan 0001,