Several studies have revealed evidences on the substantial role of Vascular endothelial growth factor-A (VEGF-A) in enhancing neovascularization processes. Some studies have shown the efficacy of intravitreal Avastin in reducing level of VEGF-A to improve NVG. On the other hand, recent pathological studies demonstrated that neutralization of VEGF reduced vascularity and decreased scar formation during wound healing, showing that VEGF strongly influence scar tissue formation. This may reduce the formation of encapsulated cyst after glaucoma surgeries and thus might improve the surgical success rate. The effect of subconjunctival bevacizumab as an adjunctive therapy in filtering glaucoma surgeries has been recently illustrated.~We aim to demonstrate the efficacy and safety of subconjunctival injection of Avastin as an adjunctive therapy for Ahmed valve glaucoma implant in patients with refractory glaucoma.
The investigators aim to demonstrate the efficacy and safety of subconjunctival injection of Avastin as an adjunctive therapy for Ahmed valve glaucoma implant in patients with refractory glaucoma.