Ancestry, beta-zone parapapillary atrophy (bPPA), and visual field progression in ocular hypertensive eyes in the African Descent and Glaucoma Evaluation Study (ADAGES)

Abstract

Purpose : The Ocular Hypertension Treatment Study (OHTS) recently reported that bPPA area and its enlargement are not significantly associated with conversion to glaucoma.[1] We tested the hypotheses that (i) bPPA at baseline and its enlargement during follow-up are associated with faster VF progression and (ii) this association differs between African Descent (AD) and European Descent (ED) subjects with OHT.

Methods : From the African Descent and Glaucoma Evaluation Study (ADAGES), 276 eyes of AD (106) and ED (170) patients with OHT and who had at least one follow-up optic disc photo were included. Two graders masked to clinical and race data reviewed the baseline and last disc photos and graded them for the presence of bPPA at baseline and ‘bPPA progression’ (development or enlargement). We investigated the relationships between (i) the presence of bPPA at baseline and ancestry group, (ii) bPPA progression and ancestry group; and (iii) bPPA at baseline and its enlargement and rates of VF progression. Mixed-effects linear models were tested with VF mean deviation as dependent variable and ‘Time’ (alone and with interaction terms) as independent variables. Interaction terms (‘Race*Baseline bPPA’ and ‘Race*bPPA Progression’) were included to test the hypothesis that the relationship between baseline bPPA and bPPA progression vs. rates of VF progression differ between ancestry groups.

Results : The prevalence of bPPA at baseline was not different between AD and ED ocular hypertensive eyes (OR= 1.08, 95% CI= 0.63 to 1.87, P=0.765). There was also no difference in bPPA progression between the two groups (OR=0 .22, 95% CI= 0.02 to 2.40, P= 0.216). Neither the presence of bPPA at baseline (P=0.820) nor its progression (P=0.807) were associated with faster VF progression in ED and AD eyes.

Conclusions : We confirmed the findings of the OHTS [1] in a cohort of AD and ED patients with OHT. Moreover, the lack of a significant association between bPPA and its enlargement with VF progression held true in both ancestry groups. Our data (from an accompanying abstract) suggests that this relationship may change once glaucomatous damage is established.

[1] - OHTS. Ophthalmology. 2015; 122:79-86

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.