Comparison of anterior corneal curvature measurements using a Galilei dual Scheimpflug analyzer and Topcon auto kerato-refractometer

Abstract

Purpose. To compare anterior corneal keratometry (K) measurements taken by a dual Scheimpflug analyzer and an auto kerato-refractometer. Methods. Sixty-four normal eyes underwent keratometric measurements with both devices. The repeatability of the auto kerato-refractometer measurements was assessed by calculating the coefficient of variation (COV). The interdevice agreement was evaluated using the Bland-Altman analysis, Pearson correlation coefficient, and paired two-tailed t -test. Results. The COV of the flat K and steep K measurements taken by the auto kerato-refractometer were 0.21% and 0.29%, respectively. There were no significant differences between the steep K and average K measurements for the Topcon and Galilei devices (P = 0.475, and P = 0.137, resp.). The Galilei flat K values were lower than those of the Topcon (P = 0.002). Both of the instruments showed good agreement for all anterior corneal keratometric values. There was a significant linear correlation between the Galilei and Topcon devices for the flat K (r = 0.989, P < 0.0001), steep K (r = 0.987, P < 0.0001), and average K values (r = 0.994, P < 0.0001). Conclusions. The anterior corneal flat keratometric values were not interchangeable between the Galilei and Topcon devices. However, the measurements of the two instruments showed significant linear correlation with each other. © 2014 Xiaogang Wang et al.