Comparison of Keratometry Measurement Values between HTG-1 and Pentacam According to ISO19980

• Published in: Annals of Optometry and Contact Lens Vol. 24; no. 2; pp. 57 - 66
• Main Authors: Choi, Yun Seok, Choi, Seung Yong
• Format: Journal Article
• Language: English
• Published: 25.06.2025
• ISSN: 2384-0919; 2384-0927
• DOI: 10.52725/aocl.2025.24.2.57

Purpose: This study compared the keratometry values obtained from the HTG-1 (Huvitz, Anyang, Korea) and the Scheimpflug-based Pentacam HR (Oculus, Wetzlar, Germany) in accordance with ISO19980:2012. The study aimed to assess the repeatability, reproducibility, and agreement between the devices, thereby evaluating the clinical validity of the HTG-1 as a corneal topographer.Methods: A total of 75 eyes from 75 subjects were examined for corneal curvature measurements following the ISO19980:2012 standards. The measurements were taken in the central (3 mm zone), middle (5 mm zone), outer (7 mm zone), and simulated K areas. These included steep K, flat K, mean K, astigmatism, and axis, as measured by both the HTG-1 and Pentacam HR. Astigmatism and axis were further analyzed using Jackson Cross Cylinder values (J0 and J45) through power vector transformation. Additional parameters such as corneal asphericity, white-to-white measurements, Keratoconus index, and Keratoconus prediction index were also compared. To investigate how astigmatism might influence these comparisons, subjects were divided into two groups: Group 1 with less than 1.5 D of astigmatism, and Group 2 with greater than or equal to 1.5 D, followed by subgroup analysis.Results: In Group 1 (n = 38) and Group 2 (n = 37), correlation analysis revealed statistically significant differences (p < 0.001) between HTG-1 and Pentacam HR for all corneal curvature and astigmatism measurements. However, the 95% limits of agreement from the Bland-Altman plots generally fell within the repeatability limits for all measurement zones, demonstrating a high degree of agreement between the two devices.Conclusions: Despite employing different measurement principles, the HTG-1 and Pentacam HR exhibit a strong repeatability and agreement across various keratometry values. While there is a need for some adjustment, particularly in the flat K values, the HTG-1 measurements may potentially substitute Pentacam readings in clinical practice.