Comparison of Intravitreal Steroids for Treatment of Cystoid Macular Edema Due to Retinal Vein Occlusion

R etinal vein occlusion (RVO) causes vision loss mostly because of the development of intraretinal leakage that leads to macular edema. The treatment of cystoid macular edema (CME) secondary to RVO has evolved considerably during the past decade. Anti-VEGF agents have become the standard of care for CME secondary to both branch (BRVO) and central retinal vein occlusion (CRVO). Because the underlying pathophysiologic mechanism responsible for the formation of macular edema in these conditions is driven by inflammatory mediators in addition to VEGF, a considerable number of RVO patients with CME either do not respond well to, or become recalcitrant to, anti-VEGF treatment.1,2 Administration of intravitreal steroids is an effective alternative to anti-VEGF therapy in these cases. Two intravitreal steroids available for the treatment of CME due to RVO are the dexamethasone intravitreal implant (Ozurdex, Allergan) and triamcinolone acetonide (TA). The GENEVA study evaluated the efficacy of the dexamethasone implant for the treatment of BRVO and CRVO. In addition to confirming the safety of the implant, the study also reported faster resolution of CME with treatment compared to observation. However, this study did not compare the efficacy of the dexamethasone implant with any other medication or with laser treatment.3 The SCORE study compared 1 mg or 4 mg TA with observation in CRVO and with grid laser photocoagulation in BRVO. The SCORE-CRVO trial reported a significantly greater BCVA improvement in the steroid group compared with the observation group. The SCORE-BRVO study did not find a significant difference in BCVA change between the steroid group and the grid laser group.4 Although both TA and dexamethasone are corticosteroids, their structures, availability, halflives, and costs are different. Their efficacy, side-effect profiles, and cost effectiveness have not been compared previously in the setting of CME due to RVO. The recently published OMAR study was the first designed to investigate the efficacy and the costeffectiveness of the dexamethasone intravitreal implant and intravitreal TA injection for the treatment of recalcitrant CME in patients with RVO.5