AIM: To investigate the application value of optical coherence tomography angiography(OCTA)in observing retinal microvasculature in patients with diabetic retinopathy(DR).

METHODS: Prospective research. The 84 patients(98 eyes)with DR admitted to our hospital during 2017-06/2019-12 were selected as the study group, and were further divided into non-proliferative DR group and proliferative DR group according to the degree of DR. Another 60 cases(68 eyes)with simple diabetes mellitus who underwent physical examination in our hospital during the same period were selected as the control group. The OCTA was used to quantitatively analyze the microvessels in the retinal macular area of the subject, and the built-in analysis software was used to obtain the blood flow density(SCP, DCP)of the superficial and deep parafoveal retina, the area and circumference of the foveal avascular zone(FAZ), the roundness index, full-thickness retinal blood flow density(FD-300). The differences of quantitative indexes, the correlation between OCTA parameters and DR severity and the diagnostic value of DR were compared.

RESULTS: The study group's FD-300, SCP and DCP were lower than those of the control group(t=6.476, 8.907, 5.078; all P<0.05), while the FAZ circumference and the roundness index were higher than those of the control group(t=4.380, 10.542; all P<0.05). The FD-300, SCP and DCP of the proliferative DR group were lower than those of the non-proliferative DR group(t=2.668, 3.408, 3.103; all P<0.05), while the FAZ circumference and the roundness index were higher than those of the non-proliferative DR group(t=2.550, 5.563; all P<0.05). Pearson correlation analysis shows that FD-300, SCP, DCP were negatively correlated with disease severity(r= -0.485, -0.546, -0.522; all P<0.05), FAZ circumference and morphological index were positively correlated with disease severity(r=0.426, 0.443; all P<0.05). ROC curve analysis showed that the area under the curve for FD-300, SCP, DCP, FAZ circumference, and FAZ morphological index to diagnose DR were 0.835(95%CI: 0.722-0.947), 0.806(95%CI: 0.701-0.911), 0.849(95%CI: 0.770-0.928), 0.768(95%CI: 0.641-0.896), 0.742(95%CI: 0.633-0.850), respectively.

CONCLUSION: OCTA can clearly monitor the morphology of superficial and deep capillaries in the macular area of patients with DR. The quantitative index of blood flow density is negatively correlated with the severity of the disease, which has high clinical value for the diagnosis of DR.