Abstract
Purpose: :
Our trial investigates the flicker light induced effect of Ranibizumab injections on the retinal arterial response in patients with AMD.
Methods: :
A study group of 27 patients (mean age 73.4 (SD 7,5) years, range 53-87 years) with AMD was examined before and four weeks after the first and second injection of Ranibizumab. Second injection was performed four weeks after first. Measurement of retinal arterial diameter was performed by using the Imedos Retinal Vessel Analyzer (RVA). Each examination took 350 seconds and contained three periods of flicker light stimulation (12,5Hz, 20 seconds) after 50, 150 and 250 seconds. The 30-second-period before first flicker stimulation was taken as baseline. Flicker response was defined as average alteration of retinal artery diameter in the first 10 seconds after flicker stimulus. The Statistical analysis was performed using ANOVA test for repeated measures.
Results: :
Before first injection of Ranibizumab we found no statistic significant flicker induced arterial diameter change (baseline 118.47 ±18.36µm, change after first flicker +1.25±5.45µm (P=0.342); after second flicker +0.65±4.56µm (P=0.481); after third flicker: +1.38±4.21 (P=0.114). Four weeks after first injection of Ranibizumab there was a significant flicker induced vasodilation (baseline 117.62 ±18.95µm, change after first flicker +1.86±4.46µm (P=0.006); after second flicker +3.23±7.07µm (P=0.027); after third flicker +2.92±9.92µm (P=0.125). Similar results were found four weeks after second injection of Ranibizumab (baseline 118.57 ±17.61µm, change after first flicker +1.48±2.32µm (P<0.001); after second flicker +2.53±6.72µm (p=0.025); after third flicker +1.42±3.42µm (p=0.035).
Conclusions: :
We found significant flicker responses after injection of Ranibizumab, whereas there were no significant responses before treatment. There seems to be no negative effect of Ranibizumab on retinal vessel autoregulation. Surprisingly we found an improvement of retinal vessel autoregulation after treatment.