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

Abstract Objective To investigate the impact of systolic and diastolic blood pressure (BP) dip at baseline on subsequent visual field (VF) progression in eyes with normal-tension glaucoma (NTG). Design Prospective cohort study Participants This study included 119 eyes of 119 newly-diagnosed NTG patients followed up for at least 2 years (average: 40.4 ± 16.9 months). Methods All subjects underwent baseline 24-hour ambulatory BP monitoring and measurements of intraocular pressure (IOP) and at least five serial VF examinations. Subjects were followed up as outpatients at 4–6 month intervals. VF progression was defined according to Early Manifest Glaucoma Trial criteria. The associations of VF progression with systolic BP (SBP) and diastolic BP (DBP) measured during the day and at night and other clinical variables were analyzed. Main Outcome Measures Factors associated with VF progression over time. Results During follow-up, 41 eyes (34%) showed VF progression. In the multivariate Cox regression model, lower nighttime trough DBP (hazard ratio [HR] 0.953; P = 0.023) and greater nighttime DBP dip ‘area’ (time multiplied by nighttime DBP >10 mmHg below mean daytime DBP; HR 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. Conclusions 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.