An apparatus (10) for determining a diagnostic glucose level in a human subject includes a light source (30) that produces collimated light at a selected wavelength. The collimated light is arranged such that it passes through a portion of an eye (12) of the subject and reflects off an eye lens (16) at a selected angle (.theta..sub.B) as reflected light. A polarization analyzer (70) measures a polarization of the reflected light that exits the eye (12). A path length processor (68) determines an optical path length (L.sub..lambda.) of the reflected light within an aqueous humor (22) of the eye (12). A glucose level processor (90) computes a glucose concentration based on the measured polarization and the determined optical path length (L.sub..lambda.).
Method and Apparatus for Non-invasive Measurements of Blood-glucose Levels in Humans / R. R., Ansari; Rovati, Luigi. - 6,704,588:, pp. 1-121.