A method and device for optical measurements are presented for determining
the concentration of a substance in patient's blood. Optical measurement
sessions are applied to a measurement location in a blood containing
medium during certain time period. The optical measurements include
illumination of the measurement location with incident light of at least
one selected wavelength, detection, at each measurement session, of at
least two light responses of the medium characterized by at least two
different polarization states of detected light, respectively, and
generation of data representative thereof. Measured data so obtained is in
the form of at least two time variations of the light responses of the
medium characterized by different polarization states of detected light,
respectively, a relation between the time variations being indicative of
the concentration of the substance in blood.
