The Topographic Relationship Between Choroidal Microvascular Dropout and Glaucomatous Damage in Primary Angle-Closure Glaucoma

PURPOSE: To study the topographic relationship between parapapillary choroidal microvasculature dropout (MvD) and parapapillary retinal nerve fiber layer (RNFL) defect in primary angle-closure glaucoma (PACG) eyes. METHODS: This cross-sectional study was carried out in a glaucoma clinic. Patients with PACG and healthy controls were consecutively enrolled. Each subject underwent optical coherence tomography angiography (OCTA) and OCT testing; additionally, visual field (VF) tests were also conducted in the patients with PACG. MvD was determined when choroidal layer images in OCTA showed a complete loss of the microvasculature. The study included 55 patients with PACG and 30 healthy controls. RESULTS: Fifty-five eyes in 55 patients with PACG and 30 eyes in 30 healthy controls were recruited. MvD was found in 26 PACG eyes (47.3%), but no MvD was found in the healthy eyes. Compared with PACG eyes without MvD, eyes with MvD had thinner average RNFL (P < 0.001), worse VF mean deviation (P = 0.006), and lower peripapillary vessel density (P < 0.001). Between MvD and RNFL defects, there was good topographic consistency in angular circumference (Bland–Altman 95% confidence interval [CI], −24.9° to 21.0°) and position (Bland-Altman 95% CI, −18.6° to 20.6°). There was a significant correlation between the MvD angular circumference and the average peripapillary vessel density (r = −0.505; P = 0.014), average RNFL thickness (r = −0.742; P < 0.001), and VF mean deviation (r = −0.572; P = 0.004). CONCLUSIONS: In patients with PACG, the MvD angular circumference and position were highly topographic consistent with those of the peripapillary RNFL defect area. This study suggests that there is a significant correlation between MvD and glaucoma optic nerve injury. TRANSLATIONAL RELEVANCE: Given the vascular etiology for glaucoma, the current research suggests that the MvD angular circumference may serve as a potential supplementary clue of glaucoma disease severity.