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S. A. Teucher, D. Sandner, E. Spörl, L. E. Pillunat; Autoregulation of Retinal Veins in Patients With Age Related Macular Degeneration (AMD) and the Influence of Intravitreal (IVT) Ranibizumab. Invest. Ophthalmol. Vis. Sci. 2010;51(13):2820.
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© ARVO (1962-2015); The Authors (2016-present)
We analyzed the effect of IVT ranibizumab on retinal venous response to flicker light stimuation (FLS) in comparision to arterial response in patients with AMD.
27 patients with AMD (mean age 73.4) were examined before and four weeks after the first and second IVT ranibizumab injection. Second injection was performed four weeks after first. The Imedos Retinal Vessel Analyzer (RVA) was used for measurement of the retinal vascular diameter. Each examination took 350 seconds. It contained three periods of FLS (12.5Hz, 20 seconds) after 50, 150 and 250 seconds. The 30-second-period before first FLS was defined as baseline (BL) and average alteration of retinal vascular diameter in the first 10 seconds after FLS was defined as flicker response. For statistics ANOVA for repeated measures was used.
In contrast to arteries where no significant flicker response before treatment was found (BL 118.47±18.36µm, change after 1st FLS +0.90±5.45µm (P=0.342); after 2nd FLS -0.60±4.56µm (P=0.481); after 3rd FLS +0.13±4.21 (P=0.114)), we found a statistic significant FLS induced venous diameter change before IVT ranibizumab (BL 151.02±18.63µm, change after 1st FLS +1.20±8.49µm (P=0.810); after 2nd FLS +2.93±9.23µm (P=0.171); after 3rd FLS +3.29±4.65 (P=0.001). Four weeks after first IVT ranibizumab (BL 151.87±19.30µm, change after 1st FLS +5.06±4.69µm (P<0.001); after 2nd FLS +4.51±4.66µm (P<0.001); after 3rd FLS +3.07±3.79µm (P<0.001)) and four weeks after second IVT ranibizumab (BL 149.64±18.88µm, change after 1st FLS +1.55±7.34µm (P=0.267); after 2nd FLS +3.88±4.65µm (p<0.001); after 3rd FLS +1.99±4.97µm (p=0.05)) venous results were similar.
In contrast to retinal arteries which showed no significant flicker response before treatment we found significant flicker induced vasodilatations of retinal veins in patients with AMD before IVT ranibizumab. During treatment there was no change of the retinal venous response to flicker light. Our results show that there is in contrast to retinal arteries a less disordered autoregulation of retinal veins in patients with AMD. During ranibizumab treatment autoregulation of veins remained stable. There seems to be no negative effect of IVT ranibizumab on retinal veins autoregulation.
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