Dual wavelength polarimetry for monitoring glucose in the presence of varying birefringence
Abstract
In a continuing effort to develop a noninvasive means of monitoring glucose levels
using the aqueous humor of the eye, a dual wavelength system has been developed in
order to show that varying birefringence, similar to what is seen with a moving cornea,
can be compensated. In this paper a dual wavelength, closed-loop, system was designed
and a model was developed to extract the glucose concentration information. The system
and model were tested using various concentrations of glucose in a birefringent test cell
subject to motion artifact. The results show that for a static, non-moving sample, glucose
can be predicted to within 10 mg/dl for the entire physiologic range (0-600mg/dl) for
either laser wavelength (523nm or 635nm). In the presence of moving birefringence,
each individual wavelength produced standard errors on the order of a few thousand
mg/dL. However, when the two wavelengths are combined into the developed model,
this error is less than 20mg/dL. The approach shows that multiple wavelengths can be
used to drastically reduce the error in the presence of a moving birefringent sample. This
research also shows promising preliminary results that the error is less than 25mg/dl in
presence of a motion induced cornea birefringence artifact in NZW rabbits eyes.
Citation
Wan, Qiujie (2004). Dual wavelength polarimetry for monitoring glucose in the presence of varying birefringence. Master's thesis, Texas A&M University. Texas A&M University. Available electronically from https : / /hdl .handle .net /1969 .1 /3335.