ObjectiveTo observe the correlation between the changes of area foveal avascular zone (FAZ), central foveal thickness (CFT), the thickness of the macular ganglion cell-inner plexiform layer (GCIPL) and the BCVA in type 2 diabetic mellitus patients with different fundus lesions.MethodsA prospective clinical study. Eighty-three eyes of 51 patients with type 2 diabetic mellitus were collected in Shengjing Hospital of China Medical University from January 2018 to January 2019, including 31 males and 20 females. The average age was 53.4±7.8 years. According to the diabetic retinopathy international clinical staging criteria, the patients were divided into the non-diabetic retinopathy (NDR) group with 17 patients (31 eyes), and the non-proliferative diabetic retinopathy (NPDR) group with 34 patients (52 eyes). And 13 control eyes of 8 age- and sex-matched healthy physical examination subjects (control group) were selected in this study. The BCVA examination was performed using the international standard visual acuity chart, which was converted into IogMAR visual acuity. OCT was used to measure the CFT, the mean and the minimum thickness of GCIPL. OCT angiography (OCTA) examination was applied to obtain blood flow density scan images in macular area of 3 mm × 3 mm size. The superficial FAZ area was measured by Photoshop software. The differences of the superficial FAZ area, BCVA, CFT, the mean and the minimum thickness of GCIPL in each group were statistically analyzed, and to explore the correlation between the parameters. Analysis of variance was used to compare measurement data among three groups, and chi-square test was used for the comparison of counting data among three groups. The statistical correlation was evaluated using Pearson’s correlation coefficient.ResultsThe average area of superficial FAZ area in the control group, NDR group and NPDR group were 0.314±0.103, 0.349±0.102, 0.416±0.148 mm2; the mean logMAR BCVA were 0.015±0.038, 0.029±0.059, 0.129±0.133; the mean CFT were 247.46±13.35, 244.13±25.09, 263.12±24.96 μm; the mean GCIPL thickness were 89.00±4.98, 86.06±4.43, 82.61±14.32 μm; the mean minimum GCIPL thickness were 84.85±3.18, 80.68±5.39, 71.19±19.94 μm, respectively. The superficial FAZ area, logMAR BCVA, CFT and the minimum thickness of GCIPL showed significant differences (F=4.660, 11.708, 6.891, 6.333; P=0.012, 0.000, 0.002, 0.003) among these three groups. Correlation analysis showed that the logMAR BCVA was positively correlated with the superficial FAZ area (r=0.335, P=0.001), negatively correlated with the mean GCIPL thickness (r=－0.348, P=0.001) and the minimum GCIPL thickness (r=－0.416, P=0.000), no significant correlated with the CFT (r=0.171, P=0.095). The superficial FAZ area was negatively correlated with the CFT (r=－0.262, P=0.010) and the minimum GCIPL thickness (r=－0.213, P=0.037), no significant correlated with the mean GCIPL thickness (r=－0.179, P=0.081).ConclusionsWith the aggravation of fundus lesions in patients with type 2 diabetic mellitus, the superficial FAZ area gradually expands, the minimum GCIPL thickness gradually becomes thinner and the BCVA gradually decreases. Both the superficial FAZ area and the GCIPL thickness are correlated with BCVA. The superficial FAZ area is correlated with CFT and the minimum GCIPL thickness.