Purpose:
Anti-vascular endothelial growth factor (anti-VEGF) therapy effectively inhibits angiogenesis and vascular permeability and is an important element in the treatment of exsudative age-related macular degeneration (AMD). Retinal vessel responses to flickering light differ in various systemic and ocular diseases. In this study we investigated the short term effect of one single application of ranibizumab on retinal vessel response to flickering light in patients with exsudative AMD.
Methods:
Retinal vessel reactions to flicker stimulation were examined in 22 patients with exsudative AMD (mean age 73,1 ± 9,5 years) before and 1-3 days (mean 1,3 ± 0,57 days) after a single intravitreal injection of ranibizumab. Vessel diameters of retinal arterial and venous segments were assessed by Retinal Vessel Analyzer (Dynamic Vessel Analyzer, Zeiss® Jena, Imedos® Jena). A baseline measurement of 50 seconds was followed by 3 consecutive periods of monochromatic flicker stimulation (530-600 nm, 12,5Hz, 20s). The area under the arterial response curve was calculated mathematically to gain information about functional changes.
Results:
Mean maximal arterial and venous dilations as well as time of maximal dilation were not significantly different before and after treatment. Regarding the area under the arterial response curve 60-80 s after the flicker cessation, we found a statistically significant difference (p < 0,05) before compared to after the injection (see table for detailed results).
Conclusions:
After one single application of ranibizumab in patients with exsudative AMD there was no significant change in functional retinal arterial and venous dilation in response to flicker stimulation. We observed, though, a short term effect of the injection in terms of a significant change of the area under the arterial response curve suggesting faster arterial restoration after the treatment.
Keywords: age-related macular degeneration • vascular endothelial growth factor • blood supply