Diagnostic Ability and Discriminant Values of OCT-Angiography Parameters in Early Glaucoma Diagnosis.

Purpose: To evaluate papillary, peripapillary, and macular vasculature with optical coherence tomography angiography in preperimetric (PPG), primary open-angle glaucoma (POAG), and normal eyes, and to assess diagnostic ability and associations among the vasculature and structural damage.

Methods: This was an observational, cross-sectional study. Retinal nerve fiber layer (RNFL), ganglion cell complex thickness, whole-image (wiVD), inside disc (idVD), peripapillary (ppVD), and macular vessel densities were obtained. Analysis of variance, post hoc test, and Pearson coefficient were used. The areas under the receiver operating characteristic curve (AUC) and cut-offs were calculated.

Results: Thirteen healthy, 39 PPG, and 19 POAG eyes were included. Papillary and peripapillary VD were lower in POAG eyes in all parameters analyzed. wiVD in PPG eyes (52.37 ± 5.04%) was significantly decreased compared to healthy eyes (58.02 ± 2.02%, p < 0.05). AUC ranged from 0.62 to 0.90; the established cut-off values were 56% for wiVD, 55% for idVD, and 62% for ppVD. Pearson's correlation coefficient showed a direct correlation between the papillary or peripapillary VD and RNFL thickness.

Conclusions: Vessel densities in POAG eyes are significantly lower than in healthy eyes, and they show good discriminatory abilities. A diminished microvascular network is associated with RNFL thinning more strongly in POAG than in PPG eyes.