The benefit of reducing intraocular pressure to prevent progression of glaucoma is well documented.1 2 Despite decreased intraocular pressure some patients will, however, continue to suffer glaucomatous progression. Potentially, as yet undetermined risk factors may be present in those patients who portend progression despite seemingly adequate ocular hypotensive therapy.

Although the exact risk factors have yet to be elucidated, impaired ocular blood flow is commonly cited as a possible cause. However, conclusive evidence of its role in pathogenesis, or the benefit of improving ocular blood flow, and thereby improving patient outcomes, remains elusive.

The purpose of this review is twofold: to evaluate the data linking the pathogenesis of reduced ocular blood flow to glaucoma; and to review the benefits of improving ocular blood flow in glaucoma.

Two lines of evidence exist that potentially link impaired ocular blood flow to the pathogenesis of glaucoma: epidemiological and short-term ocular hemodynamic studies. Numerous published studies have found associations between various forms of cardiovascular disease and elevated intraocular pressure or glaucoma.3 These trials have generally linked two types of disease classes to glaucoma and ocular hypertension: chronic cardiovascular disease (i.e. systemic hypertension, diabetes or atherosclerotic heart disease) or vasospastic disorders (i.e. migraine and Raynaud’s phenomenon). The common pathological effect of these disease states is presumed to be decreased ocular perfusion pressure.

Although the majority of published data suggest a link between atherosclerotic or vasospastic disease and glaucoma, the data are inconsistent. For example, the Ocular Hypertension Treatment Study did not confirm cardiovascular disease as a risk factor …