Increased levels of vascular endothelial growth factor in the aqueous humor of patients with diabetic retinopathy

PURPOSE: This study aims to investigate the levels of aqueous vascular endothelial growth factor (VEGF) in diabetic patient groups in comparison to normal subjects, and to correlate elevated VEGF with the severity of diabetic retinopathy (DR). MATERIALS AND METHODS: Aqueous samples were obtained from 78 eyes of 74 patients undergoing intraocular surgery and they were examined by the enzyme-linked immunosorbent assay. Color photographs, optical coherence tomography scans, and fluorescein angiography were used to evaluate patients preoperatively. RESULTS: A strong statistical correlation was found to exist between the level of aqueous VEGF and the severity of DR (P < 0.001), whereas, the VEGF levels in a control group and a diabetic group without DR were not significantly different (P = 0.985). Aqueous VEGF levels were significantly elevated in patients with proliferative DR (PDR) as compared to the control group (P < 0.001), to diabetic patients without retinopathy (NDR) (P < 0.001), and to diabetic patients with nonproliferative DR (NPDR) (P < 0.001). The aqueous VEGF levels were significantly higher in patients with active PDR than in those with quiescent PDR (P = 0.001). On the other hand, a statistically insignificant (P = 0.065) correlation was found between elevated aqueous VEGF and the presence of macular edema in the NPDR group. CONCLUSIONS: VEGF was elevated in the aqueous humor of patients with DR compared to that in normal eyes. The aqueous VEGF level had a strong correlation with the severity of retinopathy along with a statistically insignificant difference in macular edema.