Abstract

DO.17.07

Flicker-induced vasodilatation in chornic smokers

Gerhard Garhöfer, Hemma Resch, Günther Weigert, Leopold Schmetterer

Universitäts-Klinik für Klinische Pharmakologie, Medizinische Universität Wien, Wien, Österreich

Objective
Habitual smoking is a risk factor for several vascular and ocular diseases. The current study was performed to test the hypothesis that the coupling between blood flow and neural activity is impaired in habitual smokers. For this purpose, flicker induced vasodilatation of retinal vessels was measured in chronic smokers and in a non smoking control group.
Methods
In this parallel group study, 24 chronic smokers and 24 age and sex matched never-smoking volunteers were included. Flicker induced vasodilatation was determined using the Dynamic Retinal Vessel Analyser. Flicker light induced vasodilatation was expressed as percent change of baseline. Intraocular pressure was determined using applanation tonometry.
Results
Intraocular pressure and mean arterial pressure were comparable in both groups. Stimulation with flicker light increased retinal venous diameter by +7.6± 3.3 in the non-smoking subjects. The flicker induced vasodilatation, however, was significantly diminished in chronic smokers (+4.9± 2.4; p<0.05). No significant difference was detected in retinal arteries between the two groups. Flicker stimulation did not affect mean arterial presser or intraocular pressure.
Conclusions
Our data indicates that flicker induced vasodilatation in retinal veins is reduced in habitual smokers compared to age matched non smoking healthy volunteers. This supports the hypothesis that chronic smoking leads to endothelial dysfunction in the eye.

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