IL1B and non-proliferative diabetic retinopathy: The inflammatory cytokine IL-1β was elevated in PDR vitreous (0.78±1.23 pg/ml) when compared to control (0.22±0.56 pg/ml; p = 0.012) or DM samples (0.23±0.42 pg/ml; p = 0.043) but not the NPDR patients (0.17±0.22 pg/ml; p = 0.090; Fig 2A).