Rebound macular edema following bevacizumab (avastin) therapy for retinal venous occlusive disease

Background: Bevacizumab, a humanized monoclonal antibody to vascular endothelial growth factor (VEGF), has been given via intravitreal injection as an off-label therapy for both neovascular age-related macular degeneration and for macular edema secondary to retinal vascular disease. The authors describe three patients with macular edema secondary to retinal venous occlusion whose edema initially responded to intravitreal bevacizumab but subsequently recurred in excess of that observed before treatment. Methods: This is a retrospective case series of three patients with macular edema secondary to retinal vein occlusion treated with intravitreal bevacizumab. Results: In all three patients, the rebound retinal edema observed was more pronounced than that present before treatment. Conclusion: These cases suggest a potential limitation of using relatively 'short-acting VEGF antagonists in retinal vascular disease of a chronic nature. Frequent repeated injections may be required to prevent a rebound effect with no clearly defined endpoint. Until the long-term safety of multiple injections of these agents is established, the authors recommend caution in using this treatment strategy.