Repeatability of Pentacam peripheral corneal thickness measurements

Purpose: To assess the repeatability of corneal thickness (CT) measurements, along the horizontal meridian up to 5. mm from centre, in healthy eyes with the Pentacam instrument. Methods: CT was measured in 82 right eyes (82 healthy subjects) at 11 corneal locations nominally 1. mm apart along the horizontal meridian with Scheimpflug topography Pentacam. Two consecutive scans were performed in quick succession. The repeatability of CT was determined by assessing differences between measurements and calculating the coefficient of variation (CV). The relative repeatability (difference) was calculated as the ratio of the absolute peripheral CT difference to the central thickness. A variant of Bland-Altman analysis was carried out to determine the effect of the overall magnitude of CT on the absolute and relative differences. Results: Mean CT (μm) at the temporal 5. mm location was 770 ± 51 and 823 ± 56 μm at the corresponding nasal location; central CT was 554 ± 36 μm Good repeatability (CV.