Intrasession repeatability of pachymetry measurements with RTVue XR 100 optical coherence tomography in normal cornea

Abstract

Purpose: To assess intra-observer reproducibility and repeatability of corneal pachymetry measurements with RTVue XR-100 anterior segment optical coherence tomography (AS-OCT) in normal cornea.

Methods: Eighty-four eyes of 84 healthy volunteers were enrolled for this study. A single examiner performed 3 successive corneal pachymetry mappings with RTVue XR-100 AS -OCT in a single session. One eye was randomly selected for the analysis. Intrasession intraexaminer reproducibility and repeatability were calculated for the minimum corneal thickness (MCT), central corneal thickness (CCT, central 0-2 mm), pericentral (2-5 mm) and peripheral (5-6 mm) annular zones of cornea, in the pachymetry mapping protocol by intraclass correlation coefficient (ICC), coefficient of variation and test retest variability.

Results: The mean CCT was 497.08 ± 32.83 µm and MCT was 490.28 ± 32.87 µm. ICC was 0.994 for CCT and 0.983 for MCT in central 2 mm zone. ICC in the pericentral 2-5 mm zones and 5-6 mm zone was lower than that in central 2 mm zone, but were still over 0.961 in 2-5 mm zone and had ICC of 0.85 in 5-6 mm zone.

Conclusion: In normal cornea, corneal thickness measurements produced highly repeatable pachymetry measurements at the central and paracentral zones (up to 6-mm diameter) which could be because of the high resolution and faster image acquisition with RTVue XR-100 OCT.

Keywords: AS-OCT; Pachymetry; Repeatability.