The role of optical coherence tomography angiography in moderate and advanced primary open-angle glaucoma

Purpose To evaluate the relationship between structure and function in moderate and advanced primary open-angle glaucoma (POAG) and to determine the accuracy of structure and vasculature for discriminating moderate from advanced POAG. Methods In this cross-sectional study, 25 eyes with moderate and 40 eyes with advanced POAG were enrolled. All eyes underwent measurement of the thickness of circumpapillary retinal nerve fiber layer (cpRNFL) and macular ganglion cell complex (GCC), and optical coherence tomography angiography (OCTA) of the optic nerve head (ONH) and macula. Visual field (VF) was evaluated by Swedish interactive threshold algorithm and 24–2 and 10–2 patterns. The correlation between structure and vasculature and the mean deviation (MD) of the VFs was evaluated by a partial correlation coefficient. The area under the receiver operating characteristic curve (AUC) was applied for assessing the power of variables for discrimination moderate from advanced POAG. Results Including all eyes, whole image vessel density (wiVD) of the ONH area, and vessel density (VD) in the inferior quadrant of perifovea were the parameters with significant correlation with the mean deviation (MD) of the VF 24–2 in OCTA of the ONH and macula (r = .649 and .397; p < .05). The greatest AUCs for discriminating moderate and advanced POAG belonged to VD of the inferior hemifield of ONH area (.886; 95% CI (.805, .967)), and VD in the inferior quadrant of perifovea (.833; 95% CI (.736, .930)) without statistically significant difference (.886 Versus .833; p = .601). Conclusion Among vascular parameters of the ONH area, wiVD had the strongest correlation with the MD of the VF 24–2 while VD of the inferior hemifield of the ONH area had the greatest AUC for discriminating moderate and advanced POAG. Vessel density in the inferior quadrant of perifovea had a significant correlation with the MD of VF 24–2 and also the greatest AUC for discriminating moderate and advanced POAG.