COLOR DOPPLER IMAGING OF OPHTHALMIC ARTERY BLOOD-FLOW VELOCITY - A STUDY OF REPEATABILITY AND AGREEMENT

Purpose: Color Doppler imaging (CDI) is a relatively new technique tha t allows quantification of blood flow velocity in orbital and ocular v asculature. Despite the numerous clinical studies that have used CDI, repeatability of this technique and agreement between observers have n ot been documented. Methods: The authors performed a prospective inves tigation of the repeatibility and agreement between observers on ophth almic artery blood flow velocity measurements in 35 patients (35 eyes) . Results: Results on the estimated error of measurement (variability between repeated readings on the same subject) indicate good repeatabi lity of the measurements; in fact, the measurement variances were only 5.6% for the peak systolic velocity, 11.4% for the end diastolic velo city, and 6.2% for the mean envelope velocity. The statistical analysi s of repeatability showed a very narrow 95% confidence interval for bo th observers. The measurement of agreement between the two observers d emonstrated the existence of a good concordance of the measurements ta ken by each observer on each subject. Conclusions: Results suggest tha t CDI is a reliable tool for quantitative assessment of opthalmic arte ry blood flow velocity.