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

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.

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.

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.

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.