The change of the level of the vascular endothelial growth factor in aqueous humor of patients with neovascular glaucoma before and after anterior retinal cryotherapy

OBJECTIVE: To compare the change of the level of the vascular endothelial growth factor (VEGF) in aqueous humor of patients with neovascular glaucoma (NVG) before and after anterior retinal cryotherapy and investigate the effects of the fluctuation of VEGF on the neovascularization of iris. METHODS: 28 patients with neovascular glaucoma were undergone iris fluorescent angiography to identify the area and amount of new vessels before and after anterior retinal cryotherapy. The neovascularization of iris was observed from 7 to 14 days by iris fluorescent angiography to confirm the regression of new vessels in iris before trabeculectomy. Samples of aqueous humor were obtained before anterior retinal cryotherapy and trabeculectomy, and 30 samples of aqueous humor from patients with senile cataract were collected as normal group. The concentrations of VEGF were measured using enzyme linked immunosorbent assay. RESULTS: the concentration of VEGF (2.096 +/- 0.512) ng/ml in aqueous humor from patients with NVG were much higher than the specimen from the patients pre-trabeculectomy (0.478 +/- 0.312) ng/ml, There was a significant difference between the two groups (t = 17.994, P < 0.01). The mean VEGF concentration of the aqueous humor from patients with senile cataract was (0.198 +/- 0.045) ng/ml which was much lower compared with the samples from patients of pre-trabeculectomy (t = 18.453, P < 0.01). CONCLUSIONS: The concentration of VEGF decline after the regression of new vessels in iris. The results suggest that VEGF play an important role in formation of iris neovascularization. Blockage the release of VEGF might reduce the occurrence of neovascular glaucoma.