Abstract
Purpose:
β-zone peripapillary atrophy (PPA) has been recognized as risk factor for glaucoma. Recently, it has been suggested that β-zone PPA should be distinctively treated on the basis of the presence of Bruch’s membrane (BM). The purpose of this study was to determine whether visual field progression was different by microstructure of β-zone PPA.
Methods:
One hundred fifty three eyes with primary open angle glaucoma (POAG) were observed for ≥2 years with at least 5 visual fields test after spectral-domain optical coherence tomography (SD-OCT, SpectralisTM HRA+OCT) examination. In SD-OCT examination, six raster scan images centered at the optic disc were obtained. Based on the extent of BM opening within β-zone PPA area, β-zone PPA was divided into PPA+BM (intact BM) and PPA-BM (lacking BM). Eyes were categorized as group A (only PPA+BM; 46 eyes), group B (both PPA+BM and PPA-BM; 89 eyes), and group C (PPA-BM; 18 eyes) on the horizontal scan image. The width of β-zone PPA, PPA+BM and PPA-BM were measured on horizontal scan and scans of 30 degrees above and below horizontal scan, and the averages of the measured values were analyzed.
Results:
The mean age of group A (65.5±11.9 years) was higher than that of the other groups (group B, 59.7±12.5 years; group C, 54.6±10.0 years; P=0.003). The mean spherical equivalent of group A (-3.1±3.7 diopters) was less myopic than that of the other groups (group B, -5.9±3.6 diopters; group C, -8.2±3.1 diopters; P <0.001). The visual field in group A progressed more rapidly (-0.38±0.44 dB/year) than those in the other groups (group B, -0.27±0.36 dB/year; group C, -0.11±0.36 dB/year; P <0.035). The mean deviation slope was significantly associated with the average width of PPA+BM (P=0.002, R=-0.247), but not with the average width of β-zone PPA (P=0.908) and PPA-BM (P=0.078).
Conclusions:
The visual field progression was different according to microstructure of β-zone PPA. The width of PPA+BM would be a risk factor for visual field progression in POAG.