Retrobulbar blood flow in glaucoma patients with nocturnal over-dipping insystemic blood pressure

PURPOSE: To evaluate the relationship between the circadian blood pressure rhythm and the retrobulbar blood flow in glaucoma patients. DESIGN: Cross-sectional study. METHODS: Circadian blood pressure measurements and color Doppler imaging (C DI) in the ophthalmic artery as well as the central retinal artery of one r andomly selected eye were obtained in 193 primary open-angle glaucoma patie nts. CDI parameters were compared by means of analysis of covariance betwee n patients with a nocturnal decrease in mean systemic blood pressure (MBP) below 20% of the average daytime MBP (over-dippers), patients with a decrea se between 10% to 20% (dippers), and patients with a decrease of less than 10% (nondippers), using age, intraocular pressure (10P), an MBP during colo r Doppler measurement as covariates. RESULTS: An analysis of covariance disclosed, after correcting for age, lop , and MBP during color Doppler imaging, a significantly lower EDV (P = .009 6) and a significantly higher RI (P = .033) in the central artery of over-d ipping glaucoma patients compared with nondippers or dippers. This effect s eemed independent of the use of vasoactive drugs. CONCLUSIONS: Glaucoma patients with a marked drop in nocturnal systemic blo od pressure seem to have altered retrobulbar blood flow parameters, suggest ing that an abnormal systemic blood pressure profile may be the manifestati on of some kind of systemic vascular dysregulation relevant for the ocular circulation. (C) 2001 by Elsevier Science Inc. All rights reserved.