Relationship between blood pressure and retrobulbar blood flow in dipper and nondipper primary open-angle glaucoma patients

Purpose: To evaluate the relationship between retrobulbar hemodynamic parameters in the ophthalmic artery (OA), central retinal artery, and short posterior ciliary artery and 24-hour blood pressure (BP) measurements in dipper and nondipper patients with primary open-angle glaucoma (POAG). Methods: A prospective, cross-sectional, and observational study was conducted on consecutive patients, referred or recruited, attending the outpatient service of our ophthalmology department. Ambulatory BP monitoring, Doppler imaging, and ocular pulse amplitude measurements were performed on the same day. Patients with nocturnal BP decrease up to 10% of the diurnal BP were defined as dippers and those with BP decrease less than 10% were defined as nondippers. Results: A total of 114 patients (36 nondippers and 78 dippers) were included in the study. The end-diastolic velocity was significantly lower and the resistivity index (RI) was significantly higher in the dippers than in the nondippers (p<0.0001 and p<0.0001, respectively). The RI in the OA was significantly correlated with daytime and nighttime systolic BP and with the daytime mean arterial pressure in the dippers. Conclusions: The RI in the OA significantly correlates with BP in patients with POAG with nocturnal BP dips. Additionally, retrobulbar blood flow parameters are reduced in dippers as compared with nondippers with POAG.