Outcome of intravitreal dexamethasone implant for the treatment of ranibizumab-resistant macular edema secondary to retinal vein occlusion

To assess the effect of intravitreal dexamethasone implant (Ozurdex) for the treatment of macular edema secondary to retinal vein occlusion (RVO) resistant to repeated intravitreal ranibizumab injection. Retrospective review of 11 patients (11 eyes) with ranibizumab-resistant macular edema secondary to RVO. Macular edema was considered refractory to ranibizumab if no change of the pattern of macular fluid on optical coherence tomography and no change of best-corrected visual acuity (BCVA) was observed after at least three consecutive monthly injections, excluding the loading dose. A single Ozurdex injection was performed and BCVA and central foveal thickness (CFT) were reviewed 2, 3, and 6 months after treatment. Mean BCVA improved significantly from 0.51 logarithm of the minimal angle of resolution (log MAR) at baseline to 0.3 log MAR (p = 0.03) at 2 months and 0.29 log MAR (p = 0.003) at 3 months. There was no significant difference in the BCVA between baseline at 6 months (p = 0.62). Mean CFT reduced significantly from 538 µm at baseline to 281 µm at 2 months (p = 0.00003), 281 µm at 3 months (p = 0.00003), and 445 µm at 6 months (p = 0.03). Treatment with Ozurdex results in improvement of BCVA and reduction of CFT in patients with ranibizumab refractory macular edema due to RVO at 3 months. However, it seems that the visual acuity gain may not last up to 6 months, so that a re-injection before this time point could be considered.