Abstract
Purpose: :
A number of previous studies have shown that blood velocities in retrobulbar arteries are reduced in primary open angle glaucoma patients (POAG), indicative for reduced blood flow to the eye. Some small scale studies also indicate that reduced flow velocities as assessed with color Doppler imaging (CDI) are a risk factor for the progression of the disease. Large scale prospective studies on this topic are, however, still missing. In the present studies we investigated the relation between blood flow velocities in retrobulbar vessels and mean arterial blood pressure in patients with POAG and healthy control subjects.
Methods: :
A total of 252 POAG patients and 198 healthy age-matched control subjects were included. Retrobulbar flow velocities were measured using CDI. Mean flow velocities (MFV) in the ophthalmic artery (OA), posterior ciliary arteries (PCAs) and the central retinal artery (CRA) were taken as the main outcome variables. Mean arterial blood pressure was measured non-invasively using automated oscillometry and intraocular pressure was measured using applanation tonometry.
Results: :
Intraocular pressure was higher in glaucoma patients than in healthy controls (p < 0.01). Mean arterial blood pressure was not different between groups. All flow velocities were significantly reduced in POAG patients as compared to healthy control subjects (p < 0.01 each). The correlation between MFV and mean arterial blood pressure was higher in POAG than in healthy control subjects for all measured vessels.
Conclusions: :
As in previous studies blood velocities in retrobulbar vessels were reduced in POAG as compared to healthy control subjects. In addition, an abnormal correlation between blood velocities and mean arterial blood pressure was found in POAG. This indicates vascular dysregulation and supports the concept that reduced ocular blood flow in glaucoma is not solely a consequence of the disease.