AIM: To evaluate the application of optical coherence tomography angiography(OCTA)in diabetic patients without retinopathy(NDR)by Meta-analysis.

METHODS: CNKI, WanFang Data, VIP, CBM, PubMed, and Embase databases were searched for relevant studies. The retrieval time was from the establishment of the database to October 2021. Two investigators independently screened the literature, extracted data and evaluated the quality of the included studies using the NOS scale. Meta-analysis and publication bias evaluation was performed using RevMan 5.3 and STATA, and sensitivity analysis was performed for results with large heterogeneity to ensure the accuracy of the results.

RESULTS: A total of 44 studies, including 2 053 patients(2 600 eyes)with NDR and 1 775 healthy control patients(2 117 eyes), were included. The Meta-analysis was performed on 17 indexes including the area and perimeters of the foveal avascular zone(FAZ), the vascular density(VD)of FAZ-300um(FD300), acircularity index(AI), VD of macular area, ganglion cell complex(GCC)thickness and retinal nerve fiber layer(RNFL)thickness. Meta-analysis results showed that the area and perimeter of FAZ in superficial capillary plexus(SCP)and deep capillary plexus(DCP)in the NDR group were higher than those of healthy control patients, and FD300, VD of macular area and RNFL thickness were all lower than those in the control group(all P<0.05); The AI values in the NDR group were slightly higher than those in the normal control group, and the GCC thickness and VD of peri-optic papillary were lower than those in the control group, but there was no differences between the groups(P>0.05).

CONCLUSIONS: Compared to the healthy control group, NDR patients had increased FAZ area and perimetry, decreased VD of macular area and RNFL thickness and early retinal microvascular damage and neurodegenerative lesions. OCTA could be used as an auxiliary tool for early diagnosis of DR.