Effect of Metformin on Macular Microcirculation in Patients with Nonproliferative Diabetic Retinopathy

目的：探讨二甲双胍对非增殖期糖尿病视网膜病变(NPDR)患者黄斑微循环的保护作用，并通过光学相干断层扫描血管成像(OCTA)技术定量评估其疗效。方法：本回顾性队列研究纳入2024年11月至2025年2月确诊的32例NPDR患者(62眼)，根据是否使用二甲双胍分为治疗组(n = 30)与对照组(n = 32)。采用OCTA测量3 mm × 3 mm扫描范围浅层/深层视网膜平均血流密度(VD)、中心凹血流密度(foveal VD)、黄斑区中心凹无血管区(FAZ)面积、周长(PERIM)、非圆指数(AI)，并使用SPSS 27.0进行统计学分析。结果：两组基线资料(性别、年龄、病程)无统计学差异(P > 0.05)。治疗组浅层视网膜VD (45.20 ± 7.61)%、深层视网膜VD (48.31 ± 6.51)%、深层foveal VD (28.05 ± 3.42)%均明显高于对照组的(43.16 ± 6.69)%、(46.50 ± 6.81)%和(26.95 ± 3.39)%，差异均有统计学意义(t = −3.974、−2.671、−2.241，均P 0.05)。治疗组FAZ面积、PERIM以及AI分别为0.313 (0.179, 0.411) mm2、2.101 (1.599, 2.432) mm和1.17 (1.08, 1.23)，明显小于对照组的0.344 (0.253, 0.487) mm2、2.179 (1.697, 2.498) mm和1.20 (1.15, 1.27)，差异均有统计学意义(Z = −4.000、−2.920和−4.400，均P Purpose: To investigate the protective effects of metformin on retinal microvascular structures in patients with non-proliferative diabetic retinopathy (NPDR) and quantitatively evaluate its efficacy using optical coherence tomography angiography (OCTA). Methods: This retrospective cohort study enrolled 32 patients (62 eyes) diagnosed with NPDR between November 2024 and February 2025. Participants were divided into a metformin-treated group (n = 30) and a control group (n = 32) based on treatment status. OCTA was utilized to measure the following parameters within a 3 × 3 mm2 macular scan: superficial/deep retinal whole-image vessel density (VD), foveal VD, foveal avascular zone (FAZ) area, perimeter (PERIM), and acircularity index (AI). Statistical analyses were performed using SPSS 27.0. Results: There were no statistically significant differences in baseline characteristics (gender, age, disease duration) between the two groups (all P > 0.05). The treatment group exhibited significantly higher values in the following parameters compared to the control group: superficial retinal vessel density (VD) [(45.20 ± 7.61)% vs. (43.16 ± 6.69)%, t = −3.974, P 0.05]. For the treatment group, the foveal avascular zone (FAZ) area, perimeter (PERIM), and acircularity index (AI) were significantly lower than those of the control group: FAZ area [0.313 (0.179~0.411) mm2 vs. 0.344 (0.253~0.487) mm2, Z = −4.000, P < 0.05], PERIM [2.101 (1.599~2.432) mm vs. 2.179 (1.697~2.498) mm, Z = −2.920, P < 0.05], and AI [1.17 (1.08~1.23) vs. 1.20 (1.15~1.27), Z = −4.400, P < 0.05]. Conclusion: OCTA observations showed that metformin delayed the progression of diabetic retinopathy (DR) by improving macular microvascular perfusion density and maintaining FAZ homeostasis.