Hammer M, Schweitzer D, Kolb A, Thamm E, Strobel J: Untersuchungen zur Messung der Sauerstoffsättigung an retinalen Gefäßen im polarisierten Licht.. Der Ophthalmologe (1999) 96 428-431

The accuracy of the spectrometric measurement of the oxygen saturation in retinal vessels is limited by it's signal to noise ratio. The aim of this study was, to investigate the possibility of the enhancement of the reflection signal by the use of polarized light.
Method: The Jena ophthalmo-spectrometer was equipped with two polarizing filters: one in the illumination and the other in front of the detector. Reflection spectra of erythrocytes streaming through a cuvette in the focus of an artificial eye were recorded. The influence of the polarization on the reflection spectra was investigated by rotating the polarizer in front of the detector. Furthermore, the degree of polarization of the light reflected from retinal vessels in vivo was determined.
Results: The degree of polarization of the light reflected from the erythrocytes was 0.6-0.8 whereas the polarization of light reflected by a standard white reflectance target was virtually zero.
Conclusion: Polarized light can be used for the reduction of the error in retinal vessel oximetry.