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.
To evaluate the effectiveness of an intravitreal bevacizumab injection on retinal neovascularization and diabetic macular edema (DME) refractory to laser photocoagulation therapy. Thirty-four eyes of 22 patients with proliferative diabetic retinopathy and DME refractory to laser photocoagulation therapy received an intravitreal injection of 1.25 mg/0.05 ml of bevazicumab. Changes in mean best-corrected visual acuity (BCVA), central macular thickness (CMT), regression of neovascularization over time, and correlation between BCVA and CMT were evaluated. Follow-up visits were at weeks 1, 2 and 4 and months 3 and 6. Mean BCVA was significantly better than baseline only at week 2 (P = 0.036). Mean CMT decreased significantly from baseline at weeks 1, 2, and 4 (P = 0.001). At months 3 and 6, mean CMT increased, albeit insignificantly (P = 0.804 and P = 1.0). The decrease in fluorescein leakage was moderate in all eyes at the end of week 1. At week 2, there was total resolution of fluorescein leakage in 24 (70.5%) eyes and moderate resolution in 10 (29.5%) eyes. At the end of month 3, the fluorescein leakage was fully resolved in 5 (14.7%) eyes, moderately resolved in 24 (70.5%) eyes, and was similar to baseline in 5 (14.7%) eyes. At month 6, the fluorescein leakage was fully resolved in 3 (8.8%) eyes, moderately resolved in 20 (58.8%) eyes, and was similar to baseline in 11 (32.4%) eyes. A moderate but insignificant negative correlation was found between visual acuity and CMT (P > 0.05). Persistence or recurrence of neovascular tissue after panretinal photocoagulation may be attributed to the production of vascular endothelial growth factor by the residual ischemic retina, which also results in persistent or recurrent DME despite macular grid photocoagulation.
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