Retinal venular oxygen saturation is associated with non-proliferative diabetic retinopathy in young patients with type 1 diabetes.

PURPOSE To determine the contribution of retinal vessel density (VD), central retinal vessel diameter and retinal oxygen (O2 ) saturation independently of other known risk factors in the development of non-proliferative diabetic retinopathy (NPDR). METHODS Macular optical coherence tomography angiography (OCTA), central retinal artery/vein equivalent diameter (CRAE/CRVE) measurements and retinal oximetry were performed in a cross-sectional study of 166 eyes from 166 individuals with type 1 diabetes (T1D) aged 14-30 years. Multiple logistic regression analysis was used to investigate whether O2 saturation, retinal vessel diameters and vessel density in the deep capillary plexus (VD-DCP) were associated with NPDR, when adjusting for known risk factors. The individuals were allocated to one group without and one group with NPDR. RESULTS Multiple logistic regression analysis showed that age (OR = 1.25, 95% CI: 1.04-1.49) and AV-difference in O2 saturation (OR = 0.85, 95% CI 0.77-0.93) were significantly associated with NPDR. CONCLUSION Our findings suggest that age and lower AV-O2 saturation difference contribute to explaining the grade of NPDR independently of other well-known risk factors. Reduced delivery of O2 to the retinal tissue is associated with the development of NPDR in young patients with T1D and should be given appropriate weight in the risk stratification at early stages of the disease.