Glaucoma and ocular blood flow: An anatomical perspective

Open-angle glaucoma (OAG) is a chronic progressive optic neuropathy that is increasing in prevalence worldwide. Currently, intraocular pressure is the only known modifiable risk factor. With lowering of intraocular pressure, the proportion of individuals who experience progression of visual field defects is reduced but continues to occur in some individuals. Many other risk factors have been identified, including decreased ocular perfusion pressure and decreased ocular blood flow. Various imaging methodologies have shown an association between OAG and altered blood flow in the various circulations: retrobulbar, retinal, optic nerve head and choroidal. In addition, different morphological alterations have been found to be associated with OAG. This review will cover the evidence that supports the association between altered ocular blood flow and glaucoma. Furthermore, it serves to describe the future methodologies that will assess ocular metabolism, which will strive to move the field closer to definitively understanding the effect of vascular changes on OAG.