Effect of conbercept combined with dexamethasone implantation on macular thickness, visual function, retinal perfusion, and inflammatory markers in patients with diabetic macular edema: A prospective controlled study

BACKGROUND: Diabetic macular edema (DME) remains a leading cause of vision impairment among adults with diabetes worldwide. Although current therapies such as anti-VEGF injections and laser treatment provide clinical benefit, the optimal approach to simultaneously target macular structure, visual function, retinal perfusion, and inflammatory activity remains uncertain. OBJECTIVE: To evaluate the efficacy of Conbercept Plus Dexamethasone compared with Conbercept alone therapy in patients with DME over a 12-month follow-up period. METHODS: Forty-six eyes from 46 patients with DME were enrolled in a prospective controlled trial and assigned to an observation group (n = 23, receiving Conbercept Plus Dexamethasone) or a control group (n = 23, Conbercept alone treatment). Central macular thickness (CMT), best-corrected visual acuity (BCVA, LogMAR), superficial vascular density (SVD), deep vascular density (DVD) were measured at baseline and at 1, 3, 6, and 12 months post-treatment. At baseline and 3 months after the fourth vitreous cavity injection, levels of interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-10 (IL-10), and vascular endothelial growth factor (VEGF) were measured in the aqueous humor. Repeated measures ANOVA and correlation analyses were performed. RESULTS: At baseline and during the first three months, CMT and BCVA did not differ between groups. At 6 and 12 months, the observation group had significantly lower CMT (236.09 ± 21.94 μm and 239.61 ± 28.77 μm) than controls (343.83 ± 60.23 μm and 322.70 ± 56.19 μm; both p < 0.001), with BCVA showing a trend toward improvement at 6 months (p = 0.060) and significant gain at 12 months (p = 0.001). DVD increased significantly in the observation group at 6 and 12 months (p = 0.018 and 0.045), while SVD remained similar. Inflammatory cytokines decreased in both groups, but reductions in IL-6, IL-8, IL-10, and VEGF were greater in the observation group (all p < 0.05). CMT strongly correlated with BCVA (r = 0.778, p < 0.001), and weak but significant correlations existed between glycemic indices and retinal parameters. CONCLUSIONS: Conbercept Plus Dexamethasone provides superior long-term structural, functional, and microvascular benefits compared with conventional therapy, likely mediated by enhanced resolution of inflammation. CMT strongly predicts visual outcomes, supporting its use as a primary surrogate marker in clinical management of DME.