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A. Kusnyerik, M. D. Resch, B. Csakany, R. Wilke, F. Gekeler, K. Boda, E. Zrenner, I. Suveges; Reliability of Ultrasound Biometry in the Equatorial Plane in Human Eyes. Invest. Ophthalmol. Vis. Sci. 2009;50(13):3700.
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© ARVO (1962-2015); The Authors (2016-present)
Besides the usual indication, such as intraocular lens calculation, in some cases/disorders the exact measurement of the equatorial diameter of the eyeball is necessary. Our purpose was to assess the interobserver reliability of ultrasound measurements in the equatorial plane in human eyes.
Twenty patients who later underwent phacoemulsification and six healthy volunteers aged between 26 and 82 years (mean, 62) were included in the study. Two masked operators measured the axial length with ultrasound applying contact 10 MHz A-scan transducer, while a third masked operator has measured the axial length using partial coherence interferometry (IOL Master, Zeiss). The horizontal (in maximal nasal gaze) and vertical (in maximal down gaze) equatorial diameters were measured by the same two masked operators. Each operator in each plane performed all measurements 10 times. Intraclass correlation coefficient (ICC) with two-way random effects model and Spearman-rank correlation was calculated.
Axial measurement with IOL Master (22,863+/-0,860 mm) showed good correlation with the ultrasonographic axial biometry results performed by both operators. Correlation coefficient (r) was 0.9963 for operator 1 and r=0.9910 for operator 2 respectively. Significant correlation could be found between mean values of operator 1 and 2: the r values were 0.988 for axial length, 0.937 for horizontal and 0.938 for vertical diameters (p<0.0001 in all cases). Intraclass correlation coefficient (ICC) revealed good reliability with high consistency (axial: 0.997, vertical: 0.921, horizontal: 0.963) and absolute agreement values (axial: 0.996, vertical: 0.916, horizontal: 0.959).
Ultrasound measurement is a well reproducible, safe and cost effective method to assess the equatorial diameter of the eyeball and it can be used to measure the dimensions of the human eye in the equatorial plane. To our best knowledge, this is the first standardized method description for the equatorial A-scan biometry.
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