Changes in retinal blood flow in patients with macular edema secondary to branch retinal vein occlusion before and after intravitreal injection of bevacizumab.

PURPOSE To investigate the effect of intravitreal bevacizumab (IVB) injections for macular edema secondary to acute branch retinal vein occlusion on the retinal microcirculation. METHODS The study was a prospective, interventional case series. Central macular thickness using spectral-domain optical coherence tomography and retinal blood flow (RBF) in untreated eyes with macular edema secondary to acute branch retinal vein occlusion in occluded (V1) and opposite venules in affected eyes (V2) and the equivalent venules in contralateral eyes (V3), using laser Doppler velocimetry during follow-up and after IVB injection, were measured. RESULTS In 33 eyes with acute branch retinal vein occlusion of <2 months of duration at the first visit, changes in the retinal microcirculation for 1 month was observed; the macular edema improved spontaneously, and the RBF was unchanged in 15 of 33 eyes, and the RBF increased by 23.3% in 18 eyes with persistent macular edema. Twenty-four eyes received an IVB injection (1.25 mg per 0.05 mL). The RBF did not change significantly during follow-up. In 8 of 24 eyes (33%) with improved macular edema 3 months after the treatment, the average RBF values before injection were significantly higher compared with that of eyes with recurrent edema. CONCLUSION One IVB injection might have little effect on the retinal microcirculation in patients with macular edema secondary to acute branch retinal vein occlusion at least 3 months after the injection. However, the increased RBF in the occluded venules before injection might be associated with improved macular edema after the IVB injection.