Comparison of corneal elevation and pachymetry measurements made by two state of the art corneal tomographers with different measurement principles

• Published in: PloS one Vol. 14; no. 10; p. e0223770
• Main Authors: Schröder, Simon, Langenbucher, Achim, Schrecker, Jens
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 16.10.2019; Public Library of Science (PLoS)
• Subjects: Aged; Aged, 80 and over; Axl protein; Biology and Life Sciences; Cataracts; Contact lenses; Cornea; Cornea - anatomy & histology; Corneal Pachymetry - instrumentation; Corneal Topography - instrumentation; Data points; Electronic devices; Engineering and Technology; Female; Humans; Male; Mathematical analysis; Medicine and Health Sciences; Middle Aged; Realignment; Reproducibility; Reproducibility of Results; Research and Analysis Methods; Standard deviation; Surgery; Thickness measurement; Topography; Ultrasonic imaging; Germany
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0223770

To compare corneal tomography measurements (elevation and pachymetry) as made by two corneal tomographers: Pentacam AXL and CASIA 2. The devices were used in a standard measuring mode. 77 normal eyes were measured five times with both devices. The data maps for anterior and posterior corneal elevation and pachymetry were exported and analyzed. Repeatability and average values were calculated for each valid data point on the exported data maps. We also calculated a corrected repeatability of the elevation data maps by removing rotation, tilt, and decentration through realignment of the elevation measurement of each eye prior to analyzing the variations in the measurement usingthe same method as for the repeatability. Pentacam AXL offered the better (corrected) repeatability for anterior corneal elevation measurements. CASIA 2 offered better repeatability for the pachymetry measurements. The tomographers could not be used interchangeably. The central corneal thickness was measured 9 μm ± 3 μm larger when measured with Pentacam AXL compared to CASIA 2.