Longitudinal Changes in Peripapillary Atrophy in the Ocular Hypertension Treatment Study : A Case–Control Assessment

PurposeTo explore the association between peripapillary atrophy (PPA) area and conversion from ocular hypertension (OHT) to glaucoma.DesignProspective, longitudinal cohort study of cases and controls.ParticipantsWe included 279 age-matched and follow-up time–matched eyes with OHT that converted to glaucoma and 279 eyes with OHT that did not convert to glaucoma.MethodsInitial and last acceptable optic disc photos were analyzed. Disc, α-zone, and β-zone PPA were traced independently by 2 trained readers and their areas were measured with Photoshop. The α-zone and β-zone areas were expressed as a percentage of optic disc area.Main Outcome Measuresα-Zone and β-zone PPA size over time.ResultsIntraclass correlation coefficients (ICCs) demonstrated that readers had good agreement on disc area (ICC = 0.97) and β-zone (ICC = 0.82), but not α-zone (ICC = 0.48). The ß-zone, as a percentage of disc area, increased in size (P < 0.001) in both eyes with incident primary open-angle glaucoma (mean, 10.6%; standard deviation, 22.6%) and matched controls (mean, 10.1%; standard deviation, 33.7) over follow-up (mean, 12.3 years). The increase in size did not differ between cases and controls (P = 0.82). Enlargement of the β-zone was not correlated with follow-up time (P = 0.39).ConclusionsThe results did not show a difference in size of the β-zone at baseline between eyes that proceed to develop glaucoma and those that do not. Moreover, the β-zone enlarges equally in case and control eyes during follow-up.