Choroidal microvasculature dropout is spatially associated with optic nerve head microvasculature loss in open-angle glaucoma

The presence of parapapillary choroidal microvasculature dropout (CMvD) may affect optic nerve head (ONH) perfusion in glaucoma patients, since parapapillary choroidal vessels provide vascular supply to the neighboring ONH. However, it remains to be determined whether the presence of parapapillary CMvD is associated with diminished perfusion in the nearby ONH. The present study investigated the spatial relationship between CMvD and ONH vessel density (ONH-VD) loss in open-angle glaucoma (OAG) eyes using optical coherence tomography angiography (OCT-A). This study included 48 OAG eyes with a single localized CMvD confined to the inferotemporal parapapillary sector and 48 OAG eyes without CMvD, matched for demographic and ocular characteristics. Global and regional ONH-VD values were compared between eyes with and without CMvD. The relationships between ONH-VD outcomes and clinical variables were assessed. ONH-VDs at the inferotemporal ONH sectors corresponding to the CMvD location were significantly lower in eyes with compared to those without CMvD. Multivariable linear regression analyses indicated that a lower inferotemporal ONH-VD was independently associated with CMvD presence and a greater CMvD angular extent (both P < 0.05). The localized presence of parapapillary CMvD in OAG eyes is significantly associated with ONH-VD loss in the neighboring ONH location, with a spatial correlation.