Association Between Nocturnal Blood Pressure Dips and Optic Disc Hemorrhage in Patients With Normal-Tension Glaucoma

Abstract

Purpose: To investigate the effect of nocturnal blood pressure (BP) dips on the occurrence of optic disc hemorrhage (ODH) in normal-tension glaucoma (NTG) patients and determine whether ODH is associated with greater likelihood of visual field progression (VFP).

Design: Prospective case-control study.

Methods: This study enrolled 698 eyes of 349 consecutive NTG patients who were ≥40 years old, underwent 24-hour intraocular pressure and ambulatory BP monitoring in the habitual position, were examined for ODH every 4-6 months with optic disc photography, and had ≥5 reliable visual field tests with minimum follow-up of 3 years. NTG patients were classified into 2 groups: "nonphysiologic" dippers, including nondippers and overdippers, and "physiologic" dippers. Odds ratios for the association between the "nonphysiologic" group and ODH were calculated using logistic regression models. Kaplan-Meier analyses were performed to compare outcomes with reference to the presence of ODH for VFP.

Results: Overall, ODH and VFP were detected in 107 (15.3%) eyes and 60 (8.6%) eyes among total 698 eyes, respectively. Overdippers showed a significantly greater frequency of ODH than nondippers or dippers. Being an overdipper was a significant and an independent risk factor for ODH occurrence during follow-up. The rates of VFP were 6%, 7%, and 24% for dippers, nondippers, and overdippers, respectively. Eyes with ODH were associated with greater likelihoods of subsequent VFP than those without. VFP occurred only in eyes with ODH.

Conclusions: Being an overdipper is a significant risk factor for ODH in NTG eyes. The detection of ODH during follow-up is a potent predictor of future VFP.