Safety and Efficacy of Dexamethasone Intravitreal Implant (Ozurdex) for the Treatment of Persistent Macular Edema Secondary to Retinal Vein Occlusion in Eyes Previously Treated with Anti-Vascular Endothelial Growth Factors

Purpose: To report our results concerning the safety and efficacy of repeated sustainedrelease dexamethasone 0.7 mg implants (Ozurdex, Allergan, Inc., Irvine, CA) in patients with persistent Macular Edema (ME) due to Retinal Vein Occlusion (RVO) previously treated with anti- VEGF injections. Patients and Methods: Ten patients (5 males and 5 females/ 5 with CRVO and 5 with BRVO), all previously treated with at least 3 consecutive anti- VEGF injections and presented lack of anatomic improvement (CRT >250μm in OCT) accompanied by lack of visual improvement (no change or deterioration of VA), received one or more Ozurdex injections (up to five). Ozurdex was administrated on an 'as needed' regimen and patients underwent a complete ophthalmological examination, including Best Corrected Visual Acuity (BCVA) measurements, biomicroscopy, tonometry, and Fourier Domain Optical Coherence Tomography (FD-OCT) on a monthly basis. Furthermore, mean time intervals for OZURDEX re-injection were estimated. Results: In 9 out of 10 cases, the patients experienced improvement in BCVA after the Ozurdex implantation with reduction in CRT. The most frequently observed adverse events included IOP elevation (20% of cases), cataract progression (10%) and cataract formation (10%). No serious systemic or topical adverse events were observed in eyes undergoing repeated Ozurdex implantations. In one of the patients, it was observed that the implant was fractured into two pieces without affecting the efficacy of the implant or causing any side effects. Conclusion: Provided the complexity of molecular mechanisms involved in ΜΕ development and the effect of corticosteroids on many of these mechanisms, in our case series, Ozurdex appeared to be a safe and beneficial treatment option for persistent ME due to RVO, in patients with poor or complete lack of response after at least 3 consecutive monthly intravitreal anti-VEGF injections. The complication rate of cataract reported in our study is relatively high compared to previous reports. This might be attributed to the multiple injections, as the incidence of cataract increases with time. Regarding IOP elevation, there is no consensus among published clinical trials on the percentage of patients requiring IOP-lowering medications. Further studies with a greater patient population as well as a control group are required in order to confirm our findings.