Factors associated with deep circulation in the peripapillary chorioretinal atrophy zone in normal-tension glaucoma with myopic disc

Purpose: To investigate factors associated with choroidal microcirculation in the peripapillary chorioretinal atrophy (PPA) zone in eyes with normal-tension glaucoma (NTG) and myopic disc. Methods: In 100 eyes of 100 NTG patients with myopic disc and 20 eyes of 20 age-matched myopic controls, 4.5 × 4.5 mm scans were made of the optic nerve head with optical coherence tomography angiography (OCTA). Peripapillary chorioretinal atrophy (PPA) area and PPA superficial choroidal image intensity (PPA-CI) were calculated with image j software. Clinical characteristics, laser speckle flowgraphy-measured mean blur rate in the temporal tissue area (temporal MT), the central thresholds (the averaged standard automated perimetry-measured visual field thresholds in the four paracentral points) and 3D-OCT-measured ganglion cell complex thickness in the papillomacular bundle (PMB-GCCT) were recorded. Results: The NTG patients had significantly lower intraocular pressure, PMB-GCCT and central threshold values, and a larger PPA area, than the controls. The area under the receiver operating characteristics curve to differentiate NTG with parafoveal scotoma (PFS) from controls was 0.76 for temporal MT, 0.85 for PPA-CI and 0.87 for PMB-GCCT. Univariate and multivariate analyses revealed that PPA-CI was negatively correlated with age, pulse rate, best-corrected visual acuity, axial length and PPA area, and positively correlated with temporal MT, PMB-GCCT and the central thresholds. Conclusion: Peripapillary chorioretinal atrophy (PPA)-CI was associated with temporal MT, ageing, bradycardia, axial length elongation and changes in central retinal structure and visual function in patients with NTG and myopic disc. Thus, microcirculation deep within the PPA zone might be a clinically useful biomarker of PFS in NTG.