Nocturnal Ophthalmic Arterial Hemodynamics in Primary Open-Angle Glaucoma

Abstract

Recent studies have found nocturnal reductions in systemic arterial blood pressure associated with progressive visual field loss in glaucoma. Although ocular ischemia has been hypothesized to link these two phenomena, it remains unknown if perfusion of the eye is reduced during the night in patients with glaucoma. Nine patients with primary open-angle glaucoma (POAG) and stable visual fields who were free from systemic hypertension, as well as nine age- and gender-matched controls, were studied at 9:00 P.M., and then during sleep at 12:00, 3:00, and 6:00 A.M. Systemic blood pressure, intraocular pressure (IOP), and color Doppler imaging (CDI) of the ophthalmic artery were measured at each time. Arterial blood pressure and ophthalmic artery peak systolic and end-diastolic velocities were similar and were unchanged over time, in both groups. In contrast, the ophthalmic arterial resistance index decreased as the night progressed (p < 0.05), identically in controls and patients. In patients with glaucoma, CDI indices were independent of changes in arterial pressure, IOP, or calculated ocular perfusion pressure. Patients with POAG characterized by stable visual fields who were free from systemic hypertension exhibited normal ophthalmic arterial hemodynamics at night; there was no evidence of ocular ischemia or vasoconstriction.