Fig. 2

Biomarker concentrations reported from each study compared between Control group and Complications group. Data represented as standardized mean difference (SMD) have been divided into two groups: one with healthy control participants and the other of individuals with clinical signs of diabetes and ocular complications. Both groups show concentrations for TNF-α, VEGF, IL-1RA, IL-1β, IL-6, and IL-8. Studies that present the concentrations of these markers for NPDR as well as PDR are listed separately. IV inverse variance, CI confidence interval, NPDR non-proliferative diabetic retinopathy, PDR proliferative diabetic retinopathy. Asterisk indicates study data was extracted using WebPlotDigitzer