Evaluation of the Effect of Hypercapnia on Vascular Function in Normal Tension Glaucoma.

Abstract

INTRODUCTION:

Altered ocular perfusion and vascular dysregulation have been reported in glaucoma. The aim of this paper was to evaluate the vascular response to a hypercapnic stimulus.

METHODS:

Twenty normal tension glaucoma (NTG) patients and eighteen age- and gender-matched controls had pulsatile ocular blood flow (POBF) measurements, systemic cardiovascular assessment, and laser Doppler digital blood flow (DBF) assessed. Measurements were taken at baseline, after 10-minutes rest, in the stable sitting and supine positions and following induction and stabilization of hypercapnia, which induced a 15% increase in end-tidal pCO2. The POBF response to hypercapnia was divided into high (>20%) and low responders (<20%).

RESULTS:

65% of NTG patients had a greater than 41% increase in POBF following CO2 rebreathing (high responders). These high responders had a lower baseline POBF, lower baseline DBF, and a greater DBF response to thermal stimulus.

CONCLUSION:

NTG patients that have a greater than 20% increase in POBF after a hypercapnic stimulus have lower baseline POBF and DBF values. This suggests that there is impaired regulation of blood flow in a significant subgroup of NTG patients. This observation may reflect a generalised dysfunction of the vascular endothelium.

• Authors: B Quill, E Henry, E Simon, C J O'Brien
• Journal: BioMed research international (Biomed Res Int) Vol. 2015 Pg. 418159 ( 2015) ISSN: 2314-6141 [Electronic] United States
• PMID: 26557667 (Publication Type: Journal Article)

Topics

• Blood Flow Velocity (physiology)
• Case-Control Studies
• Eye (physiopathology)
• Female
• Humans
• Hypercapnia (physiopathology)
• Intraocular Pressure (physiology)
• Low Tension Glaucoma (blood, physiopathology)
• Male
• Middle Aged
• Pulsatile Flow (physiology)
• Regional Blood Flow (physiology)