Vascular endothelial growth factor in fellow eyes of eyes injected with intravitreal bevacizumab

BACKGROUND: To study the effect on untreated fellow eyes of eyes treated with an intravitreal injection of bevacizumab. METHODS: Bevacizumab (1.25 mg/0.05 ml) was injected into the vitreous cavity of one eye (the first eye) as a preoperative adjunctive therapy for proliferative diabetic retinopathy; vitrectomy was performed 1 week later. Immediately after vitrectomy, bevacizumab (1.25 mg/0.05 ml) was injected into the fellow eye (the second eye) followed by vitrectomy 1 week later. Aqueous humor samples were obtained from both eyes in five cases just before intravitreal injection of bevacizumab and just before vitrectomy 1 week later. Vascular endothelial growth factor (VEGF) concentrations in the aqueous humor were measured by enzyme-linked immunosorbent assay (ELISA). RESULTS: VEGF concentrations in the aqueous humor of the first eyes ranged from 146 to 398 pg/ml (mean, 302+/-100 pg/ml) before intravitreal injection of bevacizumab; 1 week later, the VEGF concentrations in the injected eyes were less than 31 pg/ml, the lower limit of the ELISA, in all cases (p<0.001). The concentrations in the uninjected fellow eyes ranged from 181 to 551 pg/ml (mean, 382+/-119 pg/ml). CONCLUSIONS: There seemed to be no or a minimal effect of the intravitreal injections of bevacizumab on the uninjected fellow eyes.