BLOOD-FLOW VELOCITY IN THE EXTRAOCULAR VESSELS IN CHRONIC SMOKERS

Aims--To determine blood flow velocity in the extraocular vessels in h ealthy, chronic smokers and to compare these blood flow velocities wit h those of healthy nonsmokers. Methods--In 46 healthy chronic smokers and 189 healthy non-smokers, peak systolic velocity (PSV), end diastol ic velocity (EDV), and the resistivity index (RI) were measured in the ophthalmic artery (OA), central retinal artery (CRA), lateral short p osterior ciliary artery (LPCA), and medial short posterior ciliary art ery (MPCA) by means of a colour Doppler device, Siemens Quantum 2000. The maximal (max) and minimal (min) velocities were measured in the ce ntral retinal vein (CRV). Only one eye was measured in each subject, a nd right and left eyes were chosen randomly. Blood flow velocities wer e compared with one way MANOVA and t tests. The influence of age, sex, systolic and diastolic blood pressure, as well as heart rate on blood flow velocity and RI were evaluated by an analysis of covariance. The potential differences of the influence of the covariables on blood fl ow variables in smokers and nonsmokers were tested by calculating the interactions. Results--In the majority of measured vessels blood flow velocity was higher in smokers than in non-smokers. This difference wa s statistically significant in the OA, CRV, and LPCA. The RT indices w ere equal or slightly lower in smokers. Furthermore, smokers had signi ficantly lower systolic and diastolic blood pressure. Heart rate was h igher in smokers but this difference did not reach statistical signifi cance. Conclusions--Colour Doppler measurements may differ significant ly in smokers compared with non-smokers. Therefore, smoking habits sho uld be considered when interpreting colour Doppler imaging results, an d comparing different groups of diseased or healthy subjects.