The Effect of Hyperoxia on the Retinal and Optic Nerve Head Microcirculation in Smoke rs and Non-Smokers

ABSTRACT

The effect of hyperoxia and smoking on retinal and optic nerve head microcirculation, and O2 reactivity in smokers and non-smokers were investigated using HRF(Heidelberg Retinal Flowmeter). 10 eyes of 10 young healthy non-smoking volunteers and 10 eyes of 10 young healthy smoking volunteers were investigated. Blood flow measurements were performed using HRF before and after 100% oxygen was applied to the subjects. In the non-smoking group, retinal flow was reduced by 33%, retinal volume by 24%, optic nerve head flow by 16% and optic nerve head volume by 18%. In the smoking group, retinal flow was reduced by 19%, retinal volume by 16%, optic nerve head flow by 16% and optic nerve head volume by 16%. The difference of O 2 reactivity between smokers and non-smokers was statistically significant in the retinal blood flow and volume, but not significant in the optic nerve head flow and volume. These results indicate that hyperoxia leads to a decrease in capillary blood flow of the retina and optic nerve head secondary to vasoconstriction, and that smoking decreases O2 reactivity in retinal microcirculation. The findings might be based on the long term effects of nicotine on the vascular system in smokers.