Comparing ranibizumab, dexamethasone implant, and combined therapy for macular edema secondary to branch retinal vein occlusion: a clinical trial

Background Macular edema (ME) is a common complication following branch retinal vein occlusion (BRVO) and is also the main reason for visual impairment. This study aimed to compare the efficacy and safety of intravitreal ranibizumab (IVR) or dexamethasone implant (IDI) monotherapy, as well as the combination of IVR and IDI injections, in patients with ME secondary to branch retinal vein occlusion (BRVO). Methods This multicenter, prospective, and comparative study included 292 patients with unilateral ME involvement (total of 292 eyes) secondary to BRVO. The patients were randomly assigned to three groups and followed up for 12 months. Patients in group 1 (n = 96) were treated with 3-dose loading IVR injections followed by a pro re nata (PRN) regimen. Patients in group 2 (n = 98) received IVR combined with IDI injection, followed by IVR PRN regimen. Patients in group 3 (n = 98) were treated with IDI injection, followed by repeated IDI injection based on clinical necessity. Best corrected visual acuity (BCVA), central retinal thickness (CRT), complications, and frequency of injections were recorded and compared between the three groups. Results At baseline, the three groups did not differ in age, gender, duration of ME, BCVA, IOP, and CRT (P > 0.05). Mean number of total injections per eye within 12 months were 7.1 +/- 2.3 (range 4-9) in group 1, 3.7 +/- 1.5 (range 2-6) in group 2, and 1.8 +/- 0.4 (range 1-3) in group 3. There was a statistical difference in the number of injections between group 1 and group 2 (P = 0.037). Eyes in group 3 received fewer injections than those in group 2, but the difference was not statistically significant (P = 0.052). BCVA improvement and CRT reduction were achieved in all groups and there was no significant difference between the three groups at the end of the 12th month. However, IOP elevation and cataract progression were more frequent in group 3, especially in those patients who received repeated IDI injections. Conclusion Three therapeutic regimens had comparable efficacy in treating ME secondary to BRVO. Combination therapy had an advantage in maintaining good effect with fewer re-injections and complications. Trial registration information The study complied with the principles of the Declaration of Helsinki and was approved by Xi'an Aier Ancient City Eye Hospital, Xi'an Aier Eye Hospital, and Xianyang Aier Eye Hospital ethics committees (2022SF-367).