PURPOSE: To assess vascular endothelial function in patients with normal pressure glaucoma using forearm blood flow responses to intra-arterial infusions of endothelial-dependent and -independent vasoactive agents.
METHODS: Eight patients with newly diagnosed and untreated normal pressure glaucoma and eight healthy age- and sex-matched control volunteers underwent measurement of forearm blood flow using venous occlusion plethysmography. Blood flow was assessed in response to incremental doses of sodium nitroprusside (an endothelial-independent vasodilator), acetylcholine (an endothelial-dependent vasodilator) and the vasoconstrictor N(G)-monomethyl-L-arginine (an inhibitor of nitric oxide synthase).
RESULTS: Sodium nitroprusside caused a dose-related increase in forearm blood flow in patients and controls. Glaucoma patients appeared to have an increased vasodilatory response, but this was not significant (P = 0.23). Acetylcholine also induced vasodilatation in both groups, but the response was significantly reduced in the glaucoma group (P = 0.04). N(G)-monomethyl-L-arginine induced a similar degree of vasoconstriction in both groups (P = 0.76).
CONCLUSIONS: This study has shown an impairment of peripheral endothelium-mediated vasodilatation in normal pressure glaucoma. These findings would support the concept of a generalized vascular endothelial dysfunction in patients with this condition.
|Number of pages||5|
|Journal||Investigative Ophthalmology & Visual Science|
|Publication status||Published - Jul 1999|
- Blood Flow Velocity
- Brachial Artery
- Dose-Response Relationship, Drug
- Endothelium, Vascular
- Enzyme Inhibitors
- Glaucoma, Open-Angle
- Infusions, Intra-Arterial
- Intraocular Pressure
- Middle Aged
- Nitric Oxide Synthase
- Vasodilator Agents