RT info:eu-repo/semantics/article T1 Repeatability and reproducibility of Keratograph 5M corneal topography A1 Ortiz Toquero, Sara A1 Sánchez Pavón, Irene A1 Martín Herranz, Raúl K1 Optometría K1 Keratograph 5M K1 Topografía K1 Repetibilidad K1 Reproducibilidad K1 2209.15 Optometría AB Background: Corneal topography is an important diagnostic tool and highly repeatable and reproducible topographic devices are essential in eye care practice. Placido disc-based topography is one of the most widely used methods because of its high resolution and accuracy. The aim of this study was to analyse the intrasession repeatability and intersession reproducibility of measurements obtained with a Keratograph 5M in a sample of healthy subjects.Methods: Three consecutive measurements were performed with a Keratograph 5M during two sessions in 24 healthy subjects to calculate the within-subject standard deviation (Sw), repeatability and reproducibility limits, coefficient of variation (CoV), and intraclass correlation coefficient (ICC) of corneal curvature (K1, K2 and Max-K), eccentricity, corneal diameter, and corneal aberration (6-mm pupil; coma, trefoil, spherical aberration, secondary astigmatism and quadrafoil).Results: No statistically significant differences were found between the three measurements in either session (P ≥ 0.06). The corneal parameters that demonstrated the best repeatability were corneal curvature and corneal diameter with a CoV, and the ICCs ranged from 0.41% and 0.990 (corneal diameter) to 0.28% and 0.998 (K2). Eccentricity and corneal aberrations had lower repeatability results, with CoVs and ICCs ranging from 3.88% and 0.992 (spherical aberration) to 40.21% and 0.643 (quadrafoil), respectively. In the case of reproducibility, excellent results were obtained for corneal curvature and diameter measurements (CoV ≤ 0.36% and ICC ≥ 0.987), with moderate reproducibility for corneal eccentricity (CoV ≥ 2.03% and ICC ≤ 0.986), secondary astigmatism (CoV = 20.05% and ICC = 0.787), and quadrafoil (CoV = 23.55% and ICC = 0.696).Conclusions: The Keratograph 5M demonstrated excellent repeatability and reproducibility in measuring corneal curvature and corneal diameter in healthy subjects. Corneal eccentricity shows moderate accuracy, whereas corneal aberrations (except coma, trefoil, and spherical aberrations) exhibit moderate measurement reliability and should be interpreted with caution in clinical practice. PB PeerJ YR 2025 FD 2025 LK https://uvadoc.uva.es/handle/10324/79391 UL https://uvadoc.uva.es/handle/10324/79391 LA eng NO PeerJ. 2025 May 22;13:e19478. DS UVaDOC RD 07-nov-2025