Purpose: To evaluate changes of levels of erythropoietin (EPO) and VEGF in aqueous humor before and after an intravitreal injection of bevacizumab (IVB) and determine the underlying correlation between them.
Methods: This prospective study involved 21 eyes of 21 patients with surgery-required advanced neovascular glaucoma (NVG) and 20 control subjects from October 2011 through November 2012. The NVG eyes received the IVB treatment before antiglaucomatous surgery. Aqueous humor was collected at the time of the IVB injection (pre-IVB) and at the time of antiglaucomatous surgery (post-IVB). Aqueous humor and plasma VEGF and EPO levels were measured with ELISA and chemiluminescence methods, respectively.
Results: The mean aqueous humor EPO and VEGF concentrations in pre-ivb eyes were significantly higher than those of the control subjects (p 0.001), whereas plasma levels showed no significant difference. There was a statistically significant correlation between the aqueous humor epo and the VEGF concentration (R = 0.612; P = 0.003). The mean aqueous humor VEGF in post-ivb eyes dramatically decreased from 1704.83 757.82 TO 19.02 14.65 PG/ML (P 0.001). However, EPO remained almost the same: 326.60 ± 104.28 compared with 312.67 ± 103.23 mU/mL (P = 0.675).
Conclusions: The NVG eyes showed high aqueous EPO and VEGF levels, and there was a positive correlation between them. However, levels of EPO did not change after post-IVB, whereas those of VEGF decreased.
Keywords: erythropoietin; intravitreal injection of bevacizumab; neovascular glaucoma; vascular endothelial growth factor.