Figure 4. Peripheral blood mononuclear cell reactive oxygen species (PBMC ROS) levels in the different study groups. The bar columns represent the PBMC ROS level, which was expressed as mean±standard deviation (SD) of the geomean of DCF fluorescence/5x10⁵ cells among the study subjects. PBMC ROS production was found to be significantly high among nonproliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR) subjects compared to diabetes without retinopathy (DNR) subjects (p<0.0001). A further increased trend of ROS production was observed among NPDR subjects than those with PDR. However, this production was not statistically significant (p=0.1147), whereas the level of ROS was found to be significantly lower among healthy control (HC) subjects even compared to the DNR group (p<0.0001).