ULTRASOUND BIOMICROSCOPY - II - INTRAOBSERVER AND INTEROBSERVER REPRODUCIBILITY OF MEASUREMENTS

Purpose: To evaluate intraobserver and interobserver reproducibility o f measurements in images obtained by the 50 MHz Humphrey(R) Ultrasound Biomicroscope. Methods: The first stored image of central cornea, cen tral anterior chamber, and angle structures obtained at 50 examination s were measured twice by three observers. Nine different parameters me re measured in angle images and two in images of central cornea and an terior chamber. Intraobserver reproducibility was assessed by calculat ing the coefficient of variation and interobserver reproducibility by a two-ways ANOVA. Results: Intraobserver reproducibility was high for all measurements of central cornea thickness and anterior chamber dept h with a coefficient of variation (%) less than or equal to 3.8%. In a ngle images the intraobserver reproducibility of measurements,vas ofte n lower (coefficient of variation (%) 1.3-52.6%). The lower reproducib ility was most noticeable in measurements involving the less defined s tructures. Interobserver reproducibility was poor. Conclusions: Compar ison of measurements are best done of well defined structures and by o nly one observer.