Efficacy of Combined Intravitreal Bevacizumab and Dexamethasone Compared to Bevacizumab Alone for Treatment of Persistent Macular Edema Secondary to Retinal Vein Occlusion

Purpose: This study evaluated the short-term anatomical and visual outcomes and complications of simultaneous intravitreal injection of bevacizumab and dexamethasone versus bevacizumab alone in patients with persistent macular edema caused by retinal vein occlusion (RVO) admitted at Labbafinejad Medical Center. Methods: This prospective interventional study was performed on 50 eyes from 50 patients with RVO-related macular edema refractory to at least three monthly bevacizumab injections. The eligibility criteria included central macular thickness (CMT) >300 μm and <10% reduction from baseline. Patients were alternately allocated to two groups: one received monthly bevacizumab (1.25 mg) alone (monotherapy group) and the other received intravitreal bevacizumab combined with dexamethasone (200 μg) for three sessions (combination group). Best-corrected visual acuity (BCVA), CMT, and intraocular pressure (IOP) were measured at baseline and 1 month after the third injection. Results: Baseline CMT was 511.4 ± 139.05 μm in the combination group, which decreased to 417.58 ± 156.72 μm 1 month after the last injection (P = 0.004), while the reduction of CMT was not significant in the monotherapy group. In comparison, combination therapy yielded a significantly greater CMT reduction than bevacizumab monotherapy (P = 0.020). BCVA improved significantly from baseline only in the combination group (P = 0.016), though the difference in visual improvement between groups was not significant (P = 0.457). In patients with central retinal vein occlusion (CRVO), CMT reduction was notably greater with combination therapy (P = 0.015) compared to branch retinal vein occlusion (BRVO). Visual and anatomical improvements were comparable between BRVO and CRVO subgroups. Combination therapy did not increase the risk of elevated IOP. Conclusion: For treatment-resistant macular edema secondary to RVO, simultaneous intravitreal bevacizumab and dexamethasone could reduce CMT and improve BCVA more effectively than bevacizumab alone, without increasing IOP. Given the cost and limited access to dexamethasone implants, adjunctive intravitreal dexamethasone solution is a viable option for persistent macular edema secondary to RVO.