Comparison of intravitreal ranibizumab monotherapy vs. ranibizumab combined with dexamethasone implant for macular edema secondary to retinal vein occlusion

PURPOSE: To compare the efficacy and the injection number of intravitreal ranibizumab (IVR) monotherapy vs. intravitreal ranibizumab plus dexamethasone (IVR + DEX) implants for macular edema (ME) secondary to retinal vein occlusion (RVO). METHODS: This prospective, control trial comprised 96 eyes of 96 patients with ME due to non-ischemic RVO divided into two groups. The IVR monotherapy group consisted of 61 patients (29 with CRVO and 32 with BRVO) treated with ranibizumab with three consecutive loading doses at a monthly + pro re nata (three + PRN) regimen. The IVR + DEX implant group consisted of 35 patients (19 with CRVO and 16 with BRVO) treated with intravitreal ranibizumab plus DEX implant. All eyes underwent best-corrected visual acuity (BCVA, log MAR), central foveal thickness (CFT), and intraocular pressure (IOP). In case of recurrence, each group received initial medication. RESULTS: At the 12-month visit, the mean log MAR BCVA that was improved from baseline was 0.23 with the IVR group and 0.30 with the IVR + DEX group. CFT decreased on average by 420 ± 292 μm with the IVR group and 393 ± 259 μm with the IVR + DEX implant group. No significant differences were detected in BCVA improvement and CFT reduction between the two groups (p > 0.05). The mean number of injections was 5.4 in the IVR group and 3.9 in the IVR + DEX implant group (p < 0.001). The mean reinjection interval for patients with the IVR + DEX implant was 131.2 ± 8.9 days (range: 98–150). The incidence of high IOP and cataract progression were significantly higher in the IVR + DEX implant group than in the IVR group (both p < 0.001). CONCLUSION: In RVO-ME, the IVR + DEX implant did not have synergistic efficacy, providing further improvement in BCVA and a reduction in CFT. However, the IVR + DEX implant still had an advantage in reducing the number of injections and prolonging the time between injections.