Ocular vasospasm: A risk factor in the pathogenesis of low-tension glaucoma

Abstract

The typical morphological and consequent functional damage caused by disease entities covered by the term 'glaucoma' is the result of inadequate circulation to the optic nerve fibres, predominantly in the papillary region, as a result of elevated intraocular pressure. The aim of this study is classification of different forms of glaucoma on the basis of blood flow parameters. Physiological and pathophysiological aspects of ocular blood flow and of microcirculation and hemorrheology will be considered and the significance of ocular vasospasm in low-tension glaucoma discussed. The frequent occurrence of vasospasm in the nailfold capillaries and of visual field deterioration after a cold-water test demonstrates that vasospasm is an expression of different underlying phenomena. Our results show that, in patients with ocular vasospasm, treatment with a calcium antagonist brings about a clear reversal of their visual field defects.

Blood Flow Velocity in the Peripheral Circulation of Glaucoma Patients

“…The hypothesis that vasospasm is involved in the pathogenesis of glaucoma (especially LTG) is supported by a number of studies, showing evidence of both ocular and peripheral vasospasm [7, 8, 9, 13]. Drance et al [8]using laser Doppler sonography to assess finger blood flow noted that 65% of LTG patients without migraine are vasospastic compared to 26% of non-glaucomatous non-migrainous individuals.…”

Doxium® (Calcium Dobesilate) Reduces Blood Hyperviscosity and Lowers Elevated Intraocular Pressure in Patients with Diabetic Retinopathy and Glaucoma

“…although of course it may coexist with, and increase the effects of, elevated IOP. It has been stated that 'Pathological blood viscosity values can aggravate vascular obliteration when, for in stance, a rise in intraocular pressure causes the driving pressure to fall' [13].…”

“…Blood fluidity is reversibly lost if blood viscosity is abnormally elevated because of high hemat ocrit. high plasma viscosity, or increased aggregability or reduced deformability of erythrocytes [13]. The viscosity initiates a vicious circle in which decreasing flow leads to higher viscosity, which then further slows down flow, and so on [17,31].…”

Altered Autonomic Balance in Normal Tension Glaucoma

“…Abnormalities such as endothelial dysfunction, vasospastic syndrome, and autonomic dysfunctions have been implicated in the development of autoregulatory abnormalities in glaucoma. Indeed, few studies have provided evidence of disturbed autoregulation in glaucoma patients not only at the ocular level but also at the systemic level seen in those with progressive glaucoma [4][5][6][7][8].…”