Parapapillary Choroidal Microvasculature Dropout in Glaucoma

Purpose

To investigate whether the parapapillary choroidal microvasculature dropout (MvD) determined by optical coherence tomography angiography (OCTA) in glaucomatous eyes indicates a true perfusion defect and whether the MvD accurately represents the area of nonperfusion.

Design

Observational case series.

Participants

Thirty primary open-angle glaucoma (POAG) patients with choroidal MvD as determined by OCTA and 13 POAG patients without this dropout.

Methods

Peripapillary circulation was evaluated using both OCTA and indocyanine green angiography (ICGA). For OCTA, the choroidal microvasculature was evaluated using 4.5×4.5-mm choroid–disc vessel density maps of OCTA images of the optic nerve head. An MvD was identified in OCTA by the presence of a capillary dropout. A filling defect observed in ICGA was defined as a perfusion defect (_ICGPD).

Main Outcome Measures

The topographic correlations between MvD and _ICGPD determined based on their circumferential extent, location, and area.

Results

The _ICGPD was observed as a sectoral filling defect in the 30 POAG patients exhibiting MvD and appeared identical to the MvD in terms of the shape and location. The circumferential extent, location, and area of _ICGPD did not differ from those of the MvD (all P > 0.05). The _ICGPD was not found in any of the eyes not having the MvD.

Conclusions

A localized MvD observed in the parapapillary choroid using OCTA coincided with the _ICGPD detected by ICGA. These findings indicate that OCTA accurately images impaired parapapillary choroidal circulation.