AIM: To observe the vascular density of optic disc region in radial peripapillary capillaries(RPC)layer of normal people and primary open argle glaucoma(POAG)patients using OCTA, and to explore the diagnostic ability of this technique for POAG.

METHODS: This study was a cross-sectional study, including 45 patients(60 eyes)diagnosed as POAG and 48 healthy subjects(60 eyes)as normal control group. OCTA technique was used to scan the optic papilla area of all subjects, and the vascular density and longitudinal C/D ratio of RPC layer in optic papilla area were measured. Humphrey's field of view detected MD and PSD values. The correlation between vascular density and other parameters was analyzed. ROC curve and AUC were used to evaluate the diagnostic efficacy of various parameters of vascular density in patients and were compared in pairs.

RESULTS: The vascular density decreases with the aggravation of glaucoma. The correlation between capillary density and vascular density in optic disc and MD and PSD values is weak. Other vascular density parameters have strong correlation with MD and PSD values. The whole image capillary density, peripapillary capillary density, whole image vascular density, peripapillary vascular density AUC>0.9 have high diagnostic value. There was no statistical difference between among the parameters(P>0.05). The diagnostic efficacy of inside disc capillary density and inside vascular density is significantly lower than that of other parameters AUC of 0.85 and 0.88 respectively(P<0.05).

CONCLUSION:Compared with the positive control group, the vascular density in POAG group decreased significantly and became more serious with the progress of the disease. Vascular density in optic disc region is a good indicator for evaluating structural damage in POAG patients, and is of great significance in diagnosis and follow-up of POAG. However, the diagnostic efficiency of inside disc vascular density and capillary density for POAG is obviously lower than other vascular parameters.