Beta-Zone parapapillary atrophy and the velocity of glaucoma progression

Purpose: Beta-Zone parapapillary atrophy (PPA) occurs more commonly in eyes with glaucoma. Rates of glaucomatous visual field (VF) progression in eyes with and without beta-zone PPA at the time of baseline assessment were compared.

Design: Retrospective, comparative study.

Participants: Two hundred forty-five patients from the New York Glaucoma Progression Study.

Methods: Subjects with glaucomatous optic neuropathy and repeatable VF loss were assessed for eligibility. Eyes with a Heidelberg Retina Tomograph II (HRT) examination, at least 5 visual field tests after the HRT in either eye, optic disc photographs, and <6 diopters of myopia were enrolled. beta-Zone PPA was defined as a region of chorioretinal atrophy with visible sclera and choroidal vessels adjacent to the optic disc. Global rates of VF progression were determined by automated pointwise linear regression analysis. Univariate analysis included age, gender, ethnicity, central corneal thickness (CCT), refractive error, baseline mean deviation, baseline intraocular pressure (IOP), mean IOP, IOP fluctuation, disc area, rim area, rim area-to-disc area ratio, beta-zone PPA area, beta-zone PPA area-to-disc area ratio, and presence or absence of beta-zone PPA.

Main outcome measures: The relationship between beta-zone PPA and the rate and risk of glaucoma progression.

Results: Two hundred forty-five eyes of 245 patients (mean age, 69.6+/-12.3 years) were enrolled. The mean follow-up was 4.9+/-1.4 years and the mean number of VFs after HRT was 9.3+/-2.7. beta-Zone PPA was present in 146 eyes (65%). Eyes with beta-zone PPA progressed more rapidly (-0.84+/-0.8 dB/year) than eyes without it (-0.51+/-0.6 dB/year; P<0.01). Multivariate regression showed significant influence of mean IOP (hazard ratio [HR], 1.11; P<0.01), IOP fluctuation (HR, 1.17; P = 0.02), and presence of beta-zone PPA (HR, 2.59; P<0.01) on VF progression. Moderate (0.5-1.5 dB/year; P = 0.01) and fast (>1.5 dB/year; P = 0.08) global rates of progression occurred more commonly in eyes with beta-zone PPA than in eyes without it. Thinner CCT (<525 microm) had a weak but significant correlation with presence of beta-zone PPA (kappa = 0.13).

Conclusions: Eyes with beta-zone PPA are at increased risk for glaucoma progression and warrant close clinical surveillance.