The Reproducibility of BEasurements of Macular Capillary Bood Flow by Scanning Laser Doppler Flowmetry

Choi, Moon Jeoung; Kim, Hyung Chan; Kim, Ha Kyoung

Abstract

To apply retinal capillary blood flow measurements using Scanning laser Doppler Flowmetry(SLDF) to clinical use, they should be reproducible and no interpersonal difference in nomal subject. Furthermore, the method of measurements must be simple, standardized and show acceptable range of error. We studied 10 eyes of 10 healthy normal subjects. Each subject was scanned in 2 sessions which were separated by at least 2 hours. In each session, we obtained 5 scans and measured macular capillary blood flow in two elected areas from the scanning images. The coefficients of variation of volume, flow, and velocity at each area were ranged from 3.4 to 13.2% 1.4 to 16.9%, and 3.1 to 14.3%, respectively, The reproducibility of measurements was good at each corresponding areas in each subject. No statistically significant locational difference was observed(Kolmogorov-Smirnov test, p>0.05). The Spearman rank correlation coefficients(r) were volume 0.75, flow 0.71, and velocity 0.73. They showed relatively significant correlation between first and second sessions. But there were signigicant differences on interpersonal difference in all 3 parameters: volume, flow, and velocity(Kruskal-Wallis one way ANOVA test. p<0.05). The comparison of measurements between different persons was not meaningful.