Abstract:  Objective To compare the clinical efficacy and safety of IVR regimens of 1+PRN and 3+PRN for macular edema secondary to branch retinal vein occlusion (BRVO-ME). Design Retrospective case series. Participants 70 cases of BRVO-ME received intravitreal injection of ranibizumab from January 2016 to March 2018 in Tianjin Aier Eye Hospital. Methods All patients were divided into 1+PRN group and 3+PRN group according to the treatment regimen. Patients receiving PRN after one injection were classified to 1+PRN group, and patients receiving PRN after three months of continuous injection were classified to 3+PRN group. The mean LogMAR BCVA, central retinal thickness (CRT) and central choroid thickness (CCT) of the two groups of patients as well as complications during the follow-up were observed.  Main Outcome Measures BCVA, CRT, CCT. Results At the end point of observation (12 months), BCVA increased by 0.42±0.42 (P<0.05), CRT decreased by (385.96±344.23) μm (P＜0.05), CCT decreased by (13.03±54.46) μm (P>0.05) compared with the baseline in the 1+PRN group. BCVA increased by 0.43±0.39 (P＜0.05), CRT decreased by (524.74±339.20) μm (P＜0.05), CCT decreased (5.00±28.04) μm (P>0.05) compared with the baseline in the 3+PRN group. There was no significant difference between the two groups in variation of BCVA, CRT and CCT (all P>0.05). During the observation period, the average IVR injection times of the 1+PRN group were (3.50±0.99) times, and the IVR times of the 3+PRN group were (4.25±0.73) times (P＜0.05). Conclusions Both IVR treatment regimen of 1+PRN and 3+PRN have significant short-term efficacy and good safety for BRVO-ME. The 1+PRN group achieved similar visual outcomes，reducing CRT and reducing macular edema for BRVO-ME with fewer injections compared with the 3+PRN group. Both treatments had no significant effect on the CCT of BRVO-ME patients before and after treatment. (Ophthalmol CHN, 2020, 29: 63-67)

Key words: branch retinal vein occlusion, macular edema, ranibizumab