Rate and pattern of visual field decline in primary open-angle glaucoma

Abstract

Purpose: To study the rate and pattern of visual field decline in primary open-angle glaucoma.

Design: Retrospective observational case series.

Participants: Forty eyes of 40 patients with primary open-angle glaucoma that were followed longitudinally with serial Goldmann visual fields for a minimum period of 8 years in an academic institution. Eyes with any other ocular disease except for mild cataract were excluded.

Methods: Visual fields obtained with worse than 20/50 Snellen visual acuity from cataract were excluded from analysis. In the remainder (671 Goldmann visual fields), the I4e isopter was quantified manually using a grid template previously described by Esterman. The visual field was divided into central and peripheral, superior and inferior, and nasal and temporal regions, all centered at the blind spot. The rate of visual field decline was estimated for each visual field region (including the four quadrants: superonasal [SN], superotemporal [ST], inferotemporal [IT], and inferonasal [IN]) using linear regression. Asymmetry of visual field progression was determined by comparing the rates of progression among the four quadrants. Pertinent clinical factors were evaluated for association with the asymmetry of visual field progression.

Main outcome measures: Rates of visual field decline for the entire visual field and each region. Long-term clinical outcome measures, including visual acuity, cataract and cup-to-disc ratio progression, intraocular pressures, and medical and surgical interventions were also studied.

Results: The rate of visual field change was -1.3% per year for the entire visual field. The rates of visual field section change (in % per year) were -1.3 (central), -1.4 (peripheral), -1.5 (superior), -1.2 (inferior), -1.4 (nasal), -1.2 (temporal), -1.8 (SN), -1.3 (IT), -1.2 (IN), and -1.1 (ST). About half the patients showed symmetric visual field decline, whereas others showed a more asymmetric pattern. Asymmetric visual field progression was associated with the presence of disc hemorrhage, overall rate of visual field progression, and surgical intervention for glaucoma.

Conclusions: In this group of selected patients with primary open-angle glaucoma with a long-term follow-up, all sections of the visual field declined over time. Disc hemorrhage was associated with more asymmetric visual field progression, implicating focal damage to the optic disc.