AIM: To investigate the risk factors associated with the recurrence of macular edema secondary to branch retinal vein occlusion(BRVO-ME)after anti-vascular endothelial growth factor(anti-VEGF)therapy.

METHODS:A total of 32 patients(32 eyes)with BRVO-ME who were treated at the ophthalmology department of the Affiliated Hospital of Shandong Second Medical University from February 2021 to June 2022 were selected. They were treated with a 3+pro re nata (PRN)anti-VEGF regimen and followed up for 6 mo. Following 3 consecutive anti-VEGF injections, patients were categorized into a non-recurrence group and a recurrence group based on central macular thickness(CMT)measured by optical coherence tomography(OCT)at 6 mo post-treatment. Aqueous humor levels of various cytokines levels were quantified using suspension assay method. Demographic characteristics, CMT, and cytokine levels were compared between the two groups, and their correlations with the recurrence of BRVO-ME after anti-VEGF treatment were analyzed.

RESULTS:At 6 months post-treatment, ME resolved in 19 eyes(no recurrence group), while 13 eyes showed persistent or recurrent ME(recurrence group). Compared to baseline, the CMT significantly improved in both groups at 1 d, 1, and 6 mo post-treatment(all P<0.05). However, the recurrence group exhibited significantly higher baseline, 1 d and 6 mo post-treatment CMT values than the non-recurrence group(all P<0.05). The aqueous humor levels of VEGF and monocyte chemoattractant protein-1(MCP-1)at baseline were significantly higher in the recurrence group than the non-recurrence group(all P<0.05). Spearman correlation analysis revealed positive associations between baseline CMT and interlukin IL-1β, IL-5, IL-12, MCP-1 and IP-10 levels(all P<0.05). Multivariable Logistic regression analysis identified baseline CMT and MCP-1 levels as independent risk factors for BRVO-ME recurrence(OR>1, P<0.05).

CONCLUSION: Elevated baseline CMT and aqueous humor MCP-1 levels were identified as independent risk factors for BRVO-ME recurrence after anti-VEGF therapy. Patients exhibiting higher baseline CMT and MCP-1 levels demonstrated significantly increased susceptibility to recurrence.