Background: Macular edema is the main reason for decreased visual acuity (VA) in early retinal vein occlusion (RVO). Bevacizumab (Avastin, Genentech) is an anti-VEGF substance to treat macular edema triggered by hypoxia-induced expression of vascular endothelial growth factor (VEGF). Initial reports showed a significant reduction of central retinal thickness and improved visual acuity (VA) after bevacizumab injection. To date, only retrospective studies and case reports have been published on bevacizumab treatment of RVO.
Methods: In this prospective interventional case series, we evaluated the response to a single bevacizumab treatment in 21 RVO patients (14 CRVO, 7 BRVO). Study endpoints were visual acuity (VA) using ETDRS charts and central macular edema (CME) over 9 weeks.
Results: Mean VA from all 21 patients increased by more than 2 lines (2.4+/-0.4 lines; p<0.01 compared to baseline). The improvement of VA after bevacizumab injection was concordant with a decrease in central retinal thickness. Peak VA was reached between 3 and 6 weeks after injection. Between week 6 and 9 a decrease in VA was observed. This VA decrease was precipitated by an increase in CME between week 3 and 6. In subgroup analyses, patients receiving bevacizumab injection within the first 3 months after RVO showed an average VA gain of 4 lines (range 2-7 lines) compared to an average gain of 1.8 (range 1-3) and 2.5 (range 1-7) in patients receiving bevacizumab between 4-6 months and after more than 6 months, respectively.
Conclusions: Bevacizumab injection is able to improve CME and VA in RVO patients within the first 3 to 9 weeks. We did not observe any short-term adverse effects during our study. As the decrease in VA was anticipated by an increase in central retinal thickness, regular OCT examinations between week 3 and 6 may be helpful for judging the appropriate timing for re-injection in order to maintain patients within the initially reached range of VA until a new balance between inflow and outflow in the retinal circulation is reached.