Comparison Of Anterior Segment Measurements Between A Dual Schiempflug Analyzer And A Swept Source Optical Coherence Tomography.

To compare anterior segment measurements including anterior and posterior keratometry values, anterior chamber depth (ACD), central corneal thickness (CCT), and aberrations obtained by a Scheimpflug tomography (Galilei G6) and a swept source optical coherence tomography (OCT) (Casia 2).

National Health Insurance Service Ilsan Hospital

In this retrospective study, health subjects with unoperated eyes had their anterior, posterior, and total corneal curvature, central corneal thickness, spherical and higher order aberration, and anterior chamber depth measured with Galielei G6 Dual Schiempflug Analyzer (Ziemer, Port, Switzerland) and a swept source OCT (Casia 2; Tomey Corporation, Nagoya, Japan). The analyzed variables were compared for their discrepancy, and the agreement was evaluated using intraclass correlation coefficient (ICC) and Bland-Altman plots.

 

50 eyes (50 patients) were studied. There was no significant difference in total corneal curvature between the two devices, however the difference in anterior flat keratometry value and posterior steep and mean keratometry values were significant. The astigmatism axis also exhibited significant difference between the two devices. The anterior and total keratometry values showed ICC values of over 0.80, however the posterior keratometry values were all below 0.80. The astigmatism axis and diopters also showed ICC values below 0.80. The ICC values CCT and ACD were above 0.80. The Bland-Altman plot showed agreement in CCT, ACD, and spherical aberration.

Although some anterior segments including CCT and ACD showed agreement between Shiempflug analyzer and swept source OCT, the keratometry values, especially the astigmatism axis and diopter exhibited variability. Therefore, the keratometry values of the two devices should not be used interchangeably.