The purpose of this study was to evaluate the systemic effects of ranibizumab and bevacizumab by examining the plasma levels of anti-vascular endothelial growth factor (anti-VEGF) and VEGF before and after a single intravitreal injection.

Twenty-eight eyes of 28 patients with various retinal diseases were enrolled. Seventeen eyes received an injection of intravitreal bevacizumab, and 11 eyes received an injection of ranibizumab. Blood samples were collected just before and 1 day, 1 week, and 1 month after injection. Concentrations of anti-VEGF and VEGF in plasma were measured using enzyme-linked immunosorbent assay (ELISA).

In the bevacizumab group, anti-VEGF concentration before the injection was 91.0 ng/mL, while those at 1 day, 1 week, and 1 month post-injection increased to 153.6, 196.3, and 140.3 ng/mL, respectively ( p < 0.05 for all). VEGF concentration before the injection was 93.9 pg/mL, while those 1 day, 1 week, and 1 month post-injection were reduced to 40.1, 24.7, and 33.5 pg/mL, respectively ( p < 0.05 for all). However, in the ranibizumab group, no significant reductions in anti-VEGF concentration were observed. The anti-VEGF concentration before the injection was 177.6 ng/mL, while those at 1 day, 1 week, and 1 month post-injection were 177.5, 160.7, 175.3 ng/mL, respectively ( p > 0.05 for all). VEGF level also showed no significant change. VEGF concentration before the injection was 80.9 pg/mL, while those at 1 day, 1 week and 1 month post-injection were 96.7, 106.3, 106.1 pg/mL, respectively ( p > 0.05 for all).

Contrary to ranibizumab, intravitreal bevacizumab significantly lowers plasma VEGF level in patients with various retinal diseases. The study suggests the consideration of the systemic effects of intravitreal bevacizumab injection.