Dynamic cerebral autoregulation is impaired in glaucoma

Area of Science:

• Ophthalmology
• Neurology
• Physiology

Background:

• Autonomic and endothelial dysfunction are implicated in normal pressure glaucoma (NPG) and primary open angle glaucoma (POAG).
• Previous studies suggest vasomotor dysregulation and reduced peripheral and ocular blood flow in these conditions.
• Cerebral autoregulation (CA) has not been previously evaluated in NPG and POAG patients.

Purpose of the Study:

• To assess dynamic cerebral autoregulation (CA) in patients diagnosed with NPG and POAG.
• To investigate the relationship between glaucoma and the brain's ability to regulate its blood flow.

Main Methods:

• The study involved 10 NPG patients, 11 POAG patients, and 11 healthy controls.
• Cerebral blood flow velocity (CBFV) responses to mean arterial pressure (MAP) oscillations (0.1 Hz) induced by deep breathing were measured.
• Cerebral autoregulation (CA) was quantified using the autoregressive cross-spectral gain between MAP and CBFV oscillations.

Main Results:

• No significant differences in MAP oscillation power were observed across the groups.
• CBFV oscillation power was significantly higher in both NPG and POAG patients compared to controls.
• The MAP-CBFV gain, a measure of CA, was significantly elevated in NPG and POAG patients relative to controls.

Conclusions:

• Elevated transmission of MAP oscillations to CBFV in NPG and POAG suggests impaired cerebral autoregulation.
• This impaired CA may increase the risk of cerebrovascular disorders in individuals with these types of glaucoma.
• Findings highlight a potential link between glaucoma pathophysiology and cerebrovascular health.