Fig. 4

Biomarker concentrations reported from each study compared between the Diabetes group and the Complications group. Data represented as standardized mean difference (SMD) have been divided into two groups: one with diabetes participants without ocular complications, and the other showing 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