Parapapillary Deep-Layer Microvasculature Dropout and Visual Field Progression in Glaucoma

To evaluate the association between optical coherence tomography angiography (OCT-A)-derived parapapillary deep-layer microvasculature dropout and glaucomatous visual field (VF) progression. Retrospective, cohort study. A total of 138 eyes of 138 patients with primary open-angle glaucoma (mean follow-up, 5.5 years) and with ≥5 VFs prior to OCT-A imaging were included. VF progression was defined as either a Guided Progression Analysis–based “likely progression” event or a significant VF index (VFI) slope. Microvasculature dropout was defined as parapapillary deep-layer microvasculature dropout based on a qualitative analysis of OCT-A. Prevalence of dropout was compared between eyes with and without VF progression. Fifty-five eyes (39.9%) demonstrated VF progression. A higher proportion of eyes with dropout progressed than those without dropout (50/84 eyes [59.5%] vs 5/54 eyes [9.3%]; P < .001). In multivariable logistic regression analysis, mean and standard deviation intraocular pressure, optic disc hemorrhage, focal lamina cribrosa defect, and dropout were significantly associated with prior VF progression (P < .05). The VFI progression rate was significantly faster in eyes with dropout than in those without dropout (−2.23% ± 3.22%/year vs −0.05% ± 1.24%/year, respectively; P < .001), and the location of dropout and VF progression were spatially correlated. Eyes with parapapillary deep-layer microvasculature dropout detected by OCT-A had a significantly higher rate of VF progression than eyes without dropout. These findings implicate dropout as a structural parameter suggestive of past glaucomatous VF progression. Further prospective longitudinal studies are needed to elucidate the role of deep-layer microvasculature damage in the pathogenesis of glaucoma.