Venous tone in glaucoma and hypertension

The aim of this study was the assessment of physiological venous reflexes in systemically hypertensive and normotensive subjects with primary open-angle glaucoma. The experimental group consisted of 20 normotensive and 20 untreated systemically hypertensive patients with open-angle glaucoma. The control group consisted of 31 volunteers divided into two subgroups: 16 control normotensives and 15 untreated hypertensives. The assessment of venous tone changes was performed by testing venous reflexes, Venoconstriction responses to physiological stimuli were significantly decreased in normotensive glaucoma patients, compared to normotensive controls [for the Valsalva manoeuvre 93.4 +/- 80.2 vs, 413.3 +/- 335.4 venoconstrictive units (VCUs), p = 0.02, and for a deep breath 89.1 +/- 100.1 vs. 316.8 +/- 343.2 VCUs, p = 0.03]. The intensity of venous reflexes in hypertensive glaucoma patients did not differ significantly from that seen in hypertensive controls, due to a significantly weaker reflex venoconstriction in hypertensive controls when compared to normotensive controls subjects. This study confirmed the presence of venous dysregulation in subjects with primary open-angle glaucoma and visual field loss as a part of an autonomic dysfunction. Systemic hypertension does not make this condition worse.