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[Age-related contractility of retinal arterioles during pure oxygen breathing]
1Augenklinik der Friedrich-Schiller-Universität, Bachstrasse 18, 07740 Jena.
Background:
Pure oxygen breathing is a non-invasive method to test the contractility of retinal arterioles. The normal response curve of this provocation method was tested using the Retinal Vessel Analyzer (RVA). Statistical analysis between groups was performed with th Man-Whitney test, correlations were tested with Pearsons' linear function.
Methods:
After a 3-min baseline measurement 32 healthy volunteers breathed 100% oxygen for 5 min. The diameter of an retinal arteriole was measured continuously during this provocation by the RVA. Volunteers were separated into four groups according age.
Results:
All four groups reacted to pure oxygen breathing with significant vasoconstriction of the retinal arteriole: in the youngest group (20-29 years) the reduction was 14.6 +/- 5.2% and the three older age groups 9.4 +/- 5.2%, 4.6 +/- 2.7%, and 2.8 +/- 3.3%. The correlation between vasoconstriction and age was r = 0.73.
Conclusions:
Pure oxygen breathing is an easily performed method with minimal invasiveness to the patient. However, the age-correlated response curve must be kept in mind for the clinical use of this method.