BACKGROUND This study was carried out to evaluate intraocular or systemic factors associated with the visual field damage progression in eyes with normal-tension glaucoma (NTG). METHODS Forty-seven NTG eyes with a minimum follow-up of 5 years were enrolled into the retrospective study. A stepwise regression analysis was performed to correlate the visual field damage progression, expressed as the mean deviation (MD) change per year, with several independent clinical factors including age, history of disc hemorrhage, initial MD, mean intraocular pressure (IOP), peak IOP, diurnal fluctuation of IOP, presence of a beta zone of peripapillary atrophy, and use of Ca(2+)-channel blockers. RESULTS Statistical analysis revealed that non-use of Ca(2+)-channel blockers (P = 0.01), peripapillary atrophy (P = 0.03) and disc hemorrhage (P = 0.04) were associated with visual loss progression. CONCLUSIONS Risk factors unrelated to IOP were suggested to be associated with progression of visual field loss. Systemic use of Ca(2+)-channel blockers has a favorable effect on visual field prognosis in NTG eyes.