Visual field loss in patients with normal-tension glaucoma under topical nipradilol or timolol: subgroup and subfield analyses of the nipradilol-timolol study

Abstract

Purpose: To estimate the deterioration rates of visual field loss in Japanese normal-tension glaucoma (NTG) patients under either topical nipradilol or timolol, and to explore intergroup differences in the treatment results.

Methods: A total of 146 NTG patients with mild to moderate damage were randomized to either nipradilol or timolol and followed for 3 years with a periodic comprehensive ophthalmological visual field examination (30-2 Humphrey perimeter program) every 6 months (the Nipradilol-Timolol Study). The time course of mean deviation (MD), the average total deviation (TD(mean)) in four subfields, and the corrected pattern standard deviation (CPSD) were compared between the two groups using regression analysis with a linear mixed effect model.

Results: The estimated slope for MD (dB/year) was -0.03 in the nipradilol and -0.05 in the timolol group (P > 0.4). In both groups, TD(mean) in the superior-central subfield and CPSD showed significant changes (-0.3 and 0.2-0.3, P <or= 0.001). In the patients with early visual field loss or those younger than 40 years, deterioration of some visual field parameters tended to be slower in the nipradilol group than in the timolol group.

Conclusion: During 3 years of monotherapy with either nipradilol or timolol in NTG patients, only TD(mean) in the superior-central subfield and the CPSD changed significantly without any intergroup differences.