While those with ocular hypertension (OHT) don’t exhibit impaired cerebral vasodilation responses to hypercapnia, those with primary open-angle glaucoma (POAG) do, according to a new study. Researchers theorized that impaired vasoreactivity in POAG patients may have neuronal or vascular origins.

Their study investigated changes in cerebral blood flow and vasomotor reactivity in patients with POAG and found they may have an increased risk for ischemic stroke in cases of impaired cerebral vascular regulation.

A total of 30 patients with POAG, 30 patients with OHT and 30 controls participated in the university hospital-based, cross-sectional, observational study. Using transcranial Doppler ultrasonography, the researchers measured mean blood flow velocity and breath-holding index ipsilaterally in the middle cerebral artery.

Among those with POAG, mean blood flow and breath-holding indices were significantly lower than in the control group. No difference was found between the OHT group and control group.

The researchers concluded that patients with POAG have impaired vasodilation response to hypercapnia. They presume that these neuronal changes and deterioration of the endothelium-mediated vasodilation may disrupt artery regulation in POAG patients. These patients may also experience functional insufficiency on vasoreactivity, they wrote.

Arslan GD, Olgun A, Ozcan D, et al. Assessment of cerebral vasomotor reactivity in patients with primary open angle glaucoma and ocular hypertension using the Breath-Holding Index. J Glaucoma. October 16, 2020. [Epub ahead of print].