Study explores influence of ocular blood flow in course of glaucoma.
Although results of multiple studies demonstrate the importance of ocular perfusion pressure and ocular blood flow as risk factors for glaucoma and its progression, there is insufficient evidence to conclude that vascular insults are a primary instigator to the disease process, said Alon Harris, PhD.
“More longitudinal studies are needed to gain insight in this area; OCT angiography is emerging as a tool that will allow dual-purpose assessment of structure and function. Clinical research, however, has limitations, including limitations of measurements that can be obtained in patients and the complexity of the anatomy and vascular supply of the optic nerve head. These limitations make specific determination of its relevance to glaucoma challenging,” said Dr. Harris, Letzer Endowed Professor of Ophthalmology, professor of cellular and integrative physiology, and director of clinical research, Glick Eye Center, Indiana University School of Medicine, Indianapolis.
“The use of physically-based mathematical models, however, might provide a virtual laboratory that would allow for better understanding of the importance of risk factors in isolation and their synergistic actions.”
Discussing research that is relevant to understanding how ocular blood flow might affect the course of glaucoma, Dr. Harris noted that studies clearly show ocular blood flow is altered in multiple ocular structures in patients with glaucoma, including in the optic nerve head, retina, choroid, and retrobulbar vessels.
In addition, there is an understanding that there are multiple underlying causes for the changes, including autoregulation mechanisms, vasospasm, aging, genetics, and racial influences.
Further support for the idea that vascular abnormalities are important in glaucoma pathophysiology comes from evidence of extraocular vascular abnormalities/disease in patients with glaucoma.
Vascular abnormalities have been described in the nailfold capillary bed and cerebral vasculature of patients with glaucoma, reduced renal function was found to correlate with glaucoma prevalence in one study, and patients with open angle glaucoma have also been shown to have increased risks of cardiovascular disease and stroke.
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