Effects of Intravitreally Injected Bevacizumab on Vascular Endothelial Growth Factor in Fellow Eyes

Purpose: Whether an intravitreal injection of bevacizumab in 1 eye will have any effect on the fellow eye has been discussed. The aim of this study was to determine the level of vascular endothelial growth factor (VEGF) in the fellow eyes after an intravitreal injection of bevacizumab in 1 eye with proliferative diabetic retinopathy. Methods: Eight patients who had similar findings of proliferative diabetic retinopathy in both eyes were studied. Four patients had rubeosis (rubeosis group), and 4 patients did not have rubeosis (no-rubeosis group) in the anterior chamber. All patients received an intravitreal injection of bevacizumab (1.25 mg) in 1 eye. Samples of aqueous humor were collected from the injected eyes just before the injection of bevacizumab and 1 day after the first injection just before vitrectomy. Samples of aqueous humor from the fellow eyes were collected just before a second injection of bevacizumab in the fellow eye at 7 days after the first injection. The concentration of VEGF in the aqueous humor was measured by enzyme-linked immunosorbent assay. Results: After 1 day, the concentration of VEGF in injected eyes was significantly reduced from 3,230.3 +/- 2,136.8 to 3.1 +/- 3.6 pg/mL (P < 0.05) in eyes with rubeosis and 465.0 +/- 78.8 to 0 pg/mL (P < 0.05) in those without rubeosis. After 7 days, the VEGF level of the fellow eyes was still significantly lower than that in the injected eye just before the injection of bevacizumab (688.5 +/- 443.1 pg/mL) in the rubeosis group, and it was 7.8 +/- 13.2 pg/mL in the no-rubeosis group (P < 0.05). Conclusions: A single intravitreal injection of bevacizumab significantly reduced the VEGF concentrations in the aqueous humor of the fellow untreated eye. Thus, we need to be observant of the fellow eyes after a unilateral injection and also examine the patients for systemic changes.