NORMAL-TENSION GLAUCOMATOUS OPTIC NEUROPATHY IS RELATED TO BLOOD PRESSURE VARIABILITY IN THE MARACAIBO AGING STUDY

Abstract

Objective: Optic nerve hypoperfusion might play a role in the pathogenesis of normal-tension glaucomatous optic neuropathy. Although the ocular perfusion pressure is partly determined by blood pressure levels, no previous study have addressed the risk of glaucomatous optic neuropathy in relation to blood pressure (BP) variability, independent of the BP level. We aimed this study o assess reading-to-reading BP variability of mean arterial pressure (MAP) in 24 h ambulatory BP recordings as risk factor for normal-tension glaucomatous optic neuropathy. Design and method: The Maracaibo Aging Study is a population-based epidemiological study conducted to investigate age-related diseases and which currently includes more than 3000 participants =>40 years of age assessed between 1998 and 2015. For the present study, we selected 93 participants who underwent cross-sectional optical coherence tomography, visual field assessment and 24 h ambulatory BP monitoring (2011–2016). Glaucoma cases were defined as normal-tension glaucomatous optic neuropathy with and without visual field defects. BP variability was reading-to reading variability of 24 h MAP, a determinant of ocular perfusion pressure, captured by a variable independent of the BP level (VIMmap). ORs were expressed per 2 mm Hg (1 SD) increment in VIMmap. Odds ratios (ORs) were adjusted for BP level and confounders summarized or not in a propensity score. Results: Among the 93 participants (87.1% women; mean age, 61.9 years), 26 had open-angle glaucomatous optic neuropathy at both eyes; 14 with and 19 without visual field defects. The ORs ratios for glaucomatous optic neuropathy, expressed per 1 SD increment in VIMmap (2 mm Hg), were 2.17 (95% confidence interval, 1.33–3.53) unadjusted; 2.20 (1.35–3.61) adjusted for 24 h MAP level only; 1.93 (1.10–3.41) with additional adjustment for age, educational attainment, high-density lipoprotein cholesterol and office hypertension, and 1.95 (1.10–3.45) in models also including intraocular pressure. Conclusions: We confirmed our a priori hypothesis that BP variability, most likely operating via hypoperfusion of the optic nerve, is a risk factor for normal-tension glaucomatous optic neuropathy. 24-H ambulatory BP monitoring might therefore help in stratifying for risk of normal-tension glaucomatous optic neuropathy.