Methods: Two hundred and seventy four eyes 144 DR treatment-naive DM patients were included. Complete ophthalmic examination was performed in each patient by a single examiner. DR was graded according to the International Clinical Diabetic Retinopathy Disease Severity scale. OCT scans were performed by an experienced technician using Cirrus HD-OCT.

Results: As we compared average GC-IPL thicknesses of patients with respect to DR stages; moderate non-proliferative diabetic retinopathy (NPDR) and no apparent DR groups showed statistically significant difference (p = 0,012); and also severe NPDR and no apparent DR groups showed statistically significant difference (p = 0,008). When we selected the patients with HbA1c?7%; we have found statistically significant difference only between no DR and severe NPDR group (p=0,013).According to DR stages; we did not find any statistically significant differences in terms of RNFL and SCT. DM duration, HbA1C levels and medications used to control DM did not show any correlation with average RNFL and GC-IPL thicknesses.

Conclusions: We found statistically significant differences in GC-IPL thicknesses but RNFL thicknesses were comparable across DR stages. Despite the absence of proliferative disease neuroretinal changes were evident in patients with good metabolic control (HbA1c?7%). The intricate relationship between neural and vascular structures requires additional insights to understand the initiation of DR. Keywords : Choroidal thickness. Diabetic retinopathy, Ganglion cell-inner plexiform layer thickness, Optical coherence tomography, Retinal nerve fiber layer thickness