To investigate whether the choroidal microvasculature dropout (CMvD) increases in size over time among open-angle glaucoma (OAG) eyes presenting with CMvD at baseline and evaluate the association between longitudinal CMvD size increases and subsequent visual field (VF) progression.

Retrospective cohort study.

This study enrolled 101 eyes from 101 consecutive patients with OAG with a localized CMvD and glaucomatous VF defects at baseline and a minimum 2-year follow-up. The angular circumference (AC) of the CMvD was determined from choroidal layer images using optical coherence tomography angiography at the baseline and final follow-up. Demographic and ocular characteristics, including the rate of retinal nerve fiber layer thickness loss and amount of CMvD AC increase during follow-up, were compared between OAG eyes with and without VF progression. Cox proportional hazard analysis was performed to identify the clinical factors associated with VF progression. The relationships between CMvD angular enlargement during follow-up and clinical factors were assessed.

CMvD angular enlargement was found in 21.8% of patients while VF progression was observed in 26.7% of the OAG eyes with CMvD during a mean 2.52-year follow-up. OAG eyes with VF progression showed a significantly greater CMvD angular enlargement. A larger increase in the CMvD AC was an independent predictor of VF progression. CMvD AC changes were significantly correlated with the rates of VF deterioration.

VF progression is significantly associated with a greater longitudinal increase in the CMvD AC in OAG eyes with CMvD. CMvD AC changes have significant correlations with the rate of VF loss.