Risk factors for visual field progression in the low-pressure glaucoma treatment study

Abstract

Purpose: To investigate risk factors associated with visual field progression in the Low-pressure Glaucoma Treatment Study, a prospective trial designed to compare the effects of the alpha2-adrenergic agonist brimonidine tartrate 0.2% to the beta-adrenergic antagonist timolol maleate 0.5% on visual function in low-pressure glaucoma. Design: Prospective cohort study. Methods: Low-pressure Glaucoma Treatment Study patients with <5 visual field tests during follow-up were included. Progression was determined using pointwise linear regression analysis, defined as the same 3 or more visual field locations with a slope more negative than -1.0 dB/year at P < 5%, on 3 consecutive tests. Ocular and systemic risk factors were analyzed using Cox proportional hazards model and further tested for independence in a multivariate model. Results: A total of 253 eyes of 127 subjects (mean age, 64.7 ± 10.9 years; mean follow-up, 40.6 ± 12 months) were analyzed. Eyes randomized to timolol progressed faster than those randomized to brimonidine (mean rates of progression, -0.38 ± 0.9 vs 0.02 ± 0.7 dB/y, P