Rates of Choroidal Microvasculature Dropout and Retinal Nerve Fiber Layer Changes in Glaucoma

To evaluate the association between rates of choroidal microvasculature dropout (MvD) change and rates of circumpapillary retinal nerve fiber layer (cpRNFL) loss in primary open-angle glaucoma (POAG) eyes.

Cohort study from clinical trial data.

A total of 91 eyes of 68 POAG patients with and without localized MvD at baseline with at least 4 visits and 2 years of follow-up with optical coherence tomography angiography (OCT-A) and OCT scans were included. Area and angular circumference of MvD were evaluated on OCT-A en face and B-scan choroidal vessel density images during the follow-up period. Joint longitudinal mixed effects models were used to estimate the rates of change in MvD area or angular circumference and RNFL thickness. Univariable and multivariable regressions were completed to identify the factors contributing to cpRNFL thinning.

MvD was identified in 53 eyes (58.2%) at baseline. Seventeen eyes (18.6%) that did not show MvD at baseline developed it over the follow-up period. Over a mean follow-up of 4.0 years, the mean rates of change in MvD area and angular circumference (95% CI) were 0.05 (0.04, 0.06) mm² per year and 13.2° (10.7°, 15.8°) per year, respectively. In multivariable models, the rate of cpRNFL thinning was significantly associated with the rates of change in MvD area and angular circumference (P = .008 and P = .009, respectively).

Rates of MvD area and angular circumference change over time were associated with concurrent rates of cpRNFL loss in POAG eyes.