Objective: To study the concentration of vascular endothelial growth factor in the aqueous humor before and after intravitreal injection of bevacizumab in eyes with proliferative diabetic retinopathy.
Methods: In this prospective, interventional case series, 1.25 mg of bevacizumab was injected into the vitreous cavity as preoperative adjunctive therapy 1 week before pars plana vitrectomy to treat proliferative diabetic retinopathy in 18 eyes in 18 patients. Aqueous humor samples were obtained just before intravitreal injection of bevacizumab and just before vitrectomy 1 week after the injection. Aqueous humor samples also were obtained in patients with cataract without diabetes mellitus (control group). The vascular endothelial growth factor concentration in the aqueous humor was measured using an enzyme-linked immunosorbent assay.
Results: Vascular endothelial growth factor concentration in the aqueous humor ranged from 146 to 676 pg/mL (mean +/- SD, 326 +/- 125 pg/mL) before intravitreal injection of bevacizumab and decreased to less than 31 pg/mL (P < .001) in all eyes 1 week after injection. Intravitreal bevacizumab therapy caused no adverse events. The concentrations in the control group ranged from 80 to 218 pg/mL (mean +/- SD, 146 +/- 40 pg/mL).
Conclusion: Intravitreal injections of bevacizumab resulted in a substantial decrease in vascular endothelial growth factor in the aqueous humor.