Response of retinal vessels and retrobulbar hemodynamics to intravitreal anti-VEGF treatment in eyes with branch retinal vein occlusion

PURPOSE. To investigate whether intravitreal ranibizumab (0.05 mL) treatment affects retinal vessel diameters and retrobulbar blood velocities in patients with acute branch retinal vein occlusion (BRVO). METHODS. Thirty patients with clinically significant macular edema secondary to BRVO were included. The duration of the study was three months. Patients were studied before and one week, one month, two months, and three months after the first ranibizumab injection. Depending on the clinical requirements, up to three ranibizumab injections were administered. Retinal vessel diameters were measured using a retinal vessel analyzer. Flow velocities in the retrobulbar central retinal artery were measured using color doppler imaging. Best-corrected visual acuity was assessed using ETDRS charts. Measurements were done in the affected as well as in the contralateral eye. RESULTS. Three patients were lost for follow up. In the remaining 27 patients, significant vasoconstriction was observed in retinal veins (P<0.001 versus baseline) and in retinal arteries (P=0.001 versus baseline) of the affected eyes. In addition, a significant reduction in flow velocities was observed in the BRVO eyes over time (peak systolic velocity: P=0.003, end diastolic velocity: P=0.003). The reduction in retinal vessel diameters and flow velocities did not correlate with changes in visual acuity or number of re-treatments. In the contralateral eyes no change in retinal blood flow parameters was seen. CONCLUSIONS. BRVO is an ischemic retinal disease. Given that ranibizumab treatment reduces retinal perfusion in these eyes the potential long-term effects of this vasoconstriction need to be considered.