Polarization microscopy allows for non-invasive imaging of highly ordered cellular structures which cannot be seen with conventional light microscopes. In IVF, the most frequently analyzed cell component is the meiotic spindle. It became clear that not only the presence of the meiotic apparatus is of prognostic potential but much rather the intensity of the birefringence may provide valuable additional information concerning the implantation behavior of the resulting embryo or blastocyst. In addition, the retardance of the inner zona layer was found to be representative for oocyte quality. Last but not least, also the male gamete has been shown to have a birefringent capacity which allows for better selection of spermatozoa prior to ICSI. It can be summarized that polarization microscopy proved to be a reliable and useful tool in selection of both oocytes stemming from healthy follicles and spermatozoa with optimal spermatogenesis.

Keywords: meiotic spindle, oocyte quality, polarization microscope, sperm selection, zona pellucida