Background To (i) evaluate the variations in the foveal avascular zone area (FAZ), vessel density (VD) and foveal ganglion cell layer (GCC) thickness changes in diabetic retinopathy (DR), as demonstrated by OCT angiography (OCTA) and (ii) correlate these variations. Methods This study was a retrospective observational case series of patients with DR. We studied a total of 64 eyes from patients with diabetic mellitus (DM), including 34 eyes with DR (DR group) and 30 eyes with DM without DR (NDR group). Additionally, 20 age-matched normal people were included as the control group. OCTA was performed using an NIDEK RS-3000 Advance device. Retinal capillary VD, FAZ area and GCC thickness were measured in the foveal regions (3*3 mm). Results The FAZ areas in the superficial (SRL) and deep capillary plexus layer (DL) were significantly enlarged in both the NDR and DR groups compared with the control group (p<0.05). In both the NDR and DR groups, the mean VD% in the SRL/DL, the SupGCC and InfGCC thickness were significantly decreased compared with the control group (P<0.05). No significant difference was observed between the NDR and DR groups for these measurements. Multivariable linear regression showed that the AvgGCC thickness was correlated with FAZ area (b=-11.372, p=0.001) and VD% (b=0.752, p=0.007) in the DL. Conclusions The FAZ area, mean VD% and GCC thickness in DR patients were differed compared with healthy controls. The AvgGCC thickness was correlated with FAZ area and VD% in the DL.