Short-term effects of a single intravitreal bevacizumab injection on retinal vessel calibre

Purpose: The aim was to investigate the short‐term effects of a single intravitreal bevacizumab injection on the retinal vessel calibre in patients with neovascular age‐related macular degeneration and in patients with diabetic macular oedema. Methods: Twelve patients with neovascular age‐related macular degeneration and eight patients with diabetic macular oedema were included in the study. All patients received an intravitreal injection of 1.25 mg bevacizumab. Red‐free fundus photographs (35°) were acquired with a fundus camera at baseline and one day, one week and one month after the intravitreal injection. Measurements of retinal vessel diameter were made of the supero‐temporal retinal venule and arteriole using the software available on the IMAGEnet program. Results: Although there appeared to be a trend towards vasoconstriction for the measurements in the diabetic macular oedema group (both for arterioles and venules at day 7) and the age‐related macular degeneration group (for venules at day 1 and for arterioles at day 7), it did not reach statistical significance (p > 0.05). Optical coherence tomography revealed a significant decrease in foveal thickness measurements in both groups at the one month visit compared with baseline. Conclusion: The results suggest that intravitreal injection of bevacizumab might induce retinal vasoconstriction; however, low numbers of subjects might have prevented the difference from reaching statistical significance. Further studies with a larger number of subjects would reveal the effect of intravitreal anti‐vascular endothelial growth factor treatment on retinal vessel diameters more clearly.