Purpose: Neovascular glaucoma is a frequent complication of vitrectomy performed to treat proliferative diabetic retinopathy (PDR). We assessed the level of vascular endothelial growth factor (VEGF) in the vitreous fluid obtained during vitrectomy and at postoperative fluid-air exchange.
Methods: We measured VEGF levels in vitreous samples from 17 eyes of 15 patients with PDR during vitrectomy and fluid samples obtained during fluid-air exchange 5 to 36 days postoperatively. Six of the 17 eyes had iris neovascularization after vitrectomy. Vascular endothelial growth factor levels also were measured in the vitreous fluid obtained from 8 eyes with a macular hole during vitrectomy and postoperative fluid-air exchange. We measured the plasma VEGF levels in all patients.
Results: The mean VEGF levels in 17 eyes with PDR were 1162.3+/-173.2 pg/ml in the vitreous samples and 1180.4+/-182.8 pg/ml in the postoperative fluid samples. The mean plasma VEGF level was 116.1+/-10.2 pg/ml in eyes with PDR, and the mean plasma VEGF level was 118.5+/-15.2 pg/ml in patients with a macular hole. The mean VEGF levels were 96.9+/-11.5 pg/ml in the vitreous samples and 73.9+/-12.3 pg/ml in the fluid samples in eyes with a macular hole.
Conclusions: A high VEGF level was maintained in the vitreous cavity after vitrectomy for PDR. The VEGF level in eyes with PDR was 10 times higher than that in the plasma. The results suggest that there is persistent secretion of VEGF into the vitreous cavity even after vitrectomy for PDR.