Baseline Systolic versus Diastolic Blood Pressure Dip and Subsequent Visual Field Progression in Normal-Tension Glaucoma

Abstract

To investigate the impact of systolic and diastolic blood pressure (DBP) dip at baseline on subsequent visual field (VF) progression in eyes with normal-tension glaucoma (NTG). Prospective cohort study. This study included 119 eyes of 119 newly diagnosed NTG patients followed up for at least 2 years (average, 40.4±16.9 months). All participants underwent baseline 24-hour ambulatory blood pressure (BP) monitoring and measurements of intraocular pressure (IOP) and at least 5 serial VF examinations. Participants were followed up as outpatients at 4- to 6-month intervals. Visual field progression was defined according to Early Manifest Glaucoma Trial criteria. The associations of VF progression with systolic BP (SBP) and DBP measured during the day and at night and other clinical variables were analyzed. Factors associated with VF progression over time. During follow-up, 41 eyes (34%) showed VF progression. In the multivariate Cox regression model, lower nighttime trough DBP (hazard ratio, 0.953; P= 0.023) and greater nighttime DBP dip area (time multiplied by nighttime DBP > 10 mmHg less than mean daytime DBP; hazard ratio, 1.017; P= 0.003) at baseline were significant predictors of subsequent VF progression. None of the SBP parameters was associated with VF progression. Nocturnal DBP dip showed a greater association with VF progression than SBP dip. Nocturnal trough DBP and DBP dip area at baseline are significant predictors of subsequent VF progression in NTG. Nocturnal DBP dip may be more relevant to future VF progression than SBP dip in NTG eyes.