β-Zone Parapapillary Atrophy and Rates of Glaucomatous Visual Field Progression: African Descent and Glaucoma Evaluation Study

Importance β-zone parapapillary atrophy (βPPA) has been reported as a risk factor for glaucoma onset and progression. Previous studies have shown that the prevalence of βPPA differs between individuals of African descent (AD) and European descent (ED). Objective To test whether the association between the presence and progression of βPPA vs visual field progression of glaucoma differs between these 2 ancestry groups. Design, Setting, and Participants In a prospective, multicenter, longitudinal cohort study, 634 individuals (1090 eyes) enrolled in the African Descent and Evaluation Study (ADAGES) with a diagnosis of glaucomatous optic neuropathy (GON) or ocular hypertension (OHT) and at least 2 disc stereophotographs were included. Two graders masked to clinical and ancestry data reviewed and graded the baseline and last disc stereophotographs for the presence of βPPA at baseline and βPPA progression (development or enlargement). Mixed-effects linear models were tested with visual field mean deviation as a dependent variable and time (alone and with interaction terms) as independent variables. ADAGES enrollment began in January 2003 and ended in July 2006; follow-up ended in 2016. Exposures Disc stereophotographs. Main Outcomes and Measures Progression of βPPA in AD and ED individuals. Results In 634 patients, a total of 814 eyes of AD (395 eyes) and ED (419) patients with GON and 276 eyes of AD (106) and ED (170) patients with OHT who were enrolled in ADAGES were analyzed. There were 336 (53.0%) women in the study; mean (SD) age was 61.9 (12.7) years. In the OHT group, the association between βPPA at baseline and visual field progression was not significantly different between AD and ED eyes (β = 0.071; 95% CI, −0.016 to 0.158; P  = .11), nor was the association between βPPA progression and visual field progression (β = 0.020; 95% CI, −0.465 to 0.506; P  = .93). In the GON group, ED eyes with baseline βPPA progressed faster than did AD eyes with baseline βPPA (β = −0.124; 95% CI, −0.241 to −0.007; P  = .04), although the association between βPPA progression and visual field progression did not differ significantly between race groups (β = −0.101; 95% CI, −0.323 to 0.119; P  = .37). Conclusions and Relevance Race had a significant effect on the association between baseline βPPA and rates of visual field progression in eyes with GON. Progression of βPPA was not associated with faster visual field progression in either racial group.