Vascular theory of the glaucomatous optic neuropathy pathogenesis: physiological and pathophysiological rationale. Part 2
The review covers some of the physiological mechanisms of ocular blood flow regulation and disorders in the aspect of glaucomatous optic neuropathy development. The ocular perfusion pressure and its relations with intraocular and blood pressure, with emphasis on the role of circadian oscillations, have been studied. The studies have shown that glaucoma is associated with a reduction in the perfusion pressure. The problems of ocular blood flow autoregulation and neurovascular interactions' role in the ocular blood flow regulation have been considered. Particular attention has been paid to the comparison of retinal and choroidal blood flow with an emphasis on the regulation of these two sources of blood supply to the retina and optic nerve. The fundamental causes of ocular blood flow disorder in glaucoma, such as endothelial dysfunction and primary vascular dysregulation, are discussed as well. The variety of factors involved in maintaining the constant ocular blood flow, making the choice of therapy problematic, has been noted. The main mechanisms that support the constancy of ocular blood flow autoregulation and causes of neurovascular interaction disorders have been describes. Thus, despite the presence of all the classic mechanisms of ocular blood flow regulation, physiology and pathophysiology of the eye hemoperfusion largely unique.