Ortiz-Toquero Sara, Sanchez Irene, Martin Raul
Departamento de Física Teórica, Atómica y Óptica, Universidad de Valladolid, Valladolid, Castilla y León, Spain.
Optometry Research Group, IOBA Eye Institute, University of Valladolid, Valladolid, Castilla y León, Spain.
PeerJ. 2025 May 22;13:e19478. doi: 10.7717/peerj.19478. eCollection 2025.
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.
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).
No statistically significant differences were found between the three measurements in either session ( ≥ 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).
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.
角膜地形图是一种重要的诊断工具，在眼科护理实践中，高度可重复和可再现的地形图设备至关重要。基于普拉西多盘的地形图因其高分辨率和准确性，是使用最广泛的方法之一。本研究的目的是分析在健康受试者样本中使用角膜地形图仪5M获得的测量值的日内重复性和日间再现性。
对24名健康受试者在两个时间段内使用角膜地形图仪5M进行连续三次测量，以计算角膜曲率（K1、K2和最大K值）、偏心率、角膜直径和角膜像差（6毫米瞳孔；彗差、三叶草像差、球差、继发性散光和四叶草像差）的受试者内标准差（Sw）、重复性和再现性极限、变异系数（CoV）和组内相关系数（ICC）。
两个时间段内的三次测量之间均未发现统计学上的显著差异（≥0.06）。显示出最佳重复性的角膜参数是角膜曲率和角膜直径，其CoV分别为0.41%和0.990（角膜直径）至0.28%和0.998（K2）。偏心率和角膜像差的重复性结果较低，CoV和ICC分别为3.88%和0.992（球差）至40.21%和0.643（四叶草像差）。在再现性方面，角膜曲率和直径测量结果优异（CoV≤0.36%且ICC≥0.987），角膜偏心率（CoV≥2.03%且ICC≤0.986）、继发性散光（CoV = 20.05%且ICC = 0.787）和四叶草像差（CoV = 23.55%且ICC = 0.696）的再现性中等。
角膜地形图仪5M在测量健康受试者的角膜曲率和角膜直径方面显示出优异的重复性和再现性。角膜偏心率显示出中等准确性，而角膜像差（除彗差、三叶草像差和球差外）的测量可靠性中等，在临床实践中应谨慎解释。
