Diabetes is a chronic metabolic disease characterized by elevated levels of blood glucose. Over time, it can lead to serious damages in the body. In the eyes, diabetic retinopathy (DR), the most common microvascular complication of diabetes, is a major cause of blindness. OCT can be used to provide high resolution images of the damages in the retina and follow their evolution over time. It is however still unclear which of the vascular or neurologic changes happen first in the development of the disease. In this work, we investigate the birefringence of the retinal nerve fiber layer (RNFL) of diabetic patients (with different stage of DR or no DR) and compare these results to healthy subject’s data. We use a PS-OCT system with an integrated retinal tracker for imaging (center wavelength of 860 nm, A-scan rate of 70 kHz). For each eye imaged, a raster scan centered on the optic nerve head (ONH) and a circular scan around the ONH (radius: 1.5mm) are taken. Considering only areas with a RNFL thickness >100 μm, birefringence values are calculated from an averaged circular tomogram for each eye. We observe a statistically significant reduced birefringence of the RNFL in the diabetic patients compared to the healthy volunteers.