Retrobulbar blood flow in glaucoma patients with nocturnal over-dipping in systemic 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 (CDI) in the ophthalmic artery as well as the central retinal artery of one randomly selected eye were obtained in 193 primary open-angle glaucoma patients. CDI parameters were compared by means of analysis of covariance between patients with a nocturnal decrease in mean systemic blood pressure (MBP) below 20% of the average daytime MBP (over-dippers), patients with a decrease between 10% to 20% (dippers), and patients with a decrease of less than 10% (nondippers), using age, intraocular pressure (IOP), and MBP during color Doppler measurement as covariates.

RESULTS

An analysis of covariance disclosed, after correcting for age, IOP, and MBP during color Doppler imaging, a significantly lower EDV (P =.0096) and a significantly higher RI (P =.033) in the central artery of over-dipping glaucoma patients compared with nondippers or dippers. This effect seemed independent of the use of vasoactive drugs .

CONCLUSIONS

Glaucoma patients with a marked drop in nocturnal systemic blood pressure seem to have altered retrobulbar blood flow parameters, suggesting that an abnormal systemic blood pressure profile may be the manifestation of some kind of systemic vascular dysregulation relevant for the ocular circulation.