Non-invasive polarimetric measurement of glucose concentration in the anterior chamber of the eye

Diabetes mellitus is one of the most common diseases in industrialized countries as well as in emerging economies such as India or China. One of the key technologies for diabetes therapy is semi-continuous monitoring of the glucose level of diabetics. Methods: Compared with skin-perforating techniques, optical measurement techniques promising good results bear the potential for high patient compliance with more frequent measurements. Due to its excellent optical properties, the anterior chamber and the aqueous humor (AH) contained therein offer promise for non-invasive in vivo glucose measurements. However, a number of strongly limiting factors, such as the precise optical properties of the eye, laser safety regulations and subconscious eye movements during the measurement period have to be considered for in vivo applications. Results: This article presents a high-resolution polarimetric measurement system that utilizes the optical rotatory dispersion (optical activity) of the glucose molecule for measurements of the glucose concentration in AH. Conclusion: Based on this example of a suitable optical measurement system, the special limitations and conditions that have to be considered for in vivo glucose measurement at the human eye are presented and analyzed. This includes the optical properties of the cornea and the anterior chamber, the impact of typical eye movements during a measurement and laser safety regulations.