Robert Herber1, Riccardo Vinciguerra, Bernardo Lopes, Frederik Raiskup, Lutz E Pillunat, Paolo Vinciguerra, Renato Ambrósio. 1. From the Department of Ophthalmology (Herber, Raiskup, Pillunat), University Hospital Carl Gustav Carus, TU Dresden, Germany; Humanitas San Pio X Hospital (R. Vinciguerra), Milan, Italy; School of Engineering (R. Vinciguerra, Lopes), University of Liverpool, United Kingdom; Rio de Janeiro Corneal Tomography and Biomechanics Study Group (Lopes, Ambrósio) and the Departments of Ophthalmology, Federal University of São Paulo (Lopes, Ambrósio), and Federal University of the State of Rio de Janeiro (Ambrósio), Brazil; Humanitas Clinical and Research (P. Vinciguerra), Rozzano, and Humanitas University (P. Vinciguerra), Department of Biomedical Sciences, Milan, Italy.
Abstract
PURPOSE: To assess the repeatability and reproducibility of dynamic corneal response (DCR) parameters obtained by ultra-high-speed Scheimpflug imaging (Corvis ST); in keratoconic patients. SETTING: Clinics in Germany, Italy, and Brazil. DESIGN: Prospective, observational study. METHODS: Patients were examined 3 times using 2 different dynamic Scheimpflug analyzers (Corvis ST) to obtain repeatability and reproducibility. The reliability of intraocular pressure (IOP), biomechanically corrected IOP (bIOP), pachymetry, and DCR parameters were assessed by the coefficient of repeatability, coefficient of variation (CoV), intraclass correlation coefficient (ICC), and within-subject standard deviation (sw). RESULTS: Ninety-eight eyes from 98 KC patients were included. The sw of the IOP and bIOP did not exceed 1.1 mm Hg. A CoV less than 10% was found in all DCR parameters and had a good to excellent accordance regarding the ICC. The Corvis Biomechanical Index showed an excellent repeatability and interdevice reproducibility of 0.918 and 0.827, respectively. Also, the tomographic biomechanical index showed an excellent repeatability of 3 Corvis ST and Pentacam measurements (ICC = 0.997). With regard to keratoconic severity, a significant increase in the CoV was found between mild and moderate stages compared with the advanced stage. Nevertheless, it did not exceed 10% of the CoV in severe keratoconic eyes. CONCLUSION: Corvis ST measurements in keratoconic eyes were highly repeatable and reproducible.
PURPOSE: To assess the repeatability and reproducibility of dynamic corneal response (DCR) parameters obtained by ultra-high-speed Scheimpflug imaging (Corvis ST); in keratoconic patients. SETTING: Clinics in Germany, Italy, and Brazil. DESIGN: Prospective, observational study. METHODS:Patients were examined 3 times using 2 different dynamic Scheimpflug analyzers (Corvis ST) to obtain repeatability and reproducibility. The reliability of intraocular pressure (IOP), biomechanically corrected IOP (bIOP), pachymetry, and DCR parameters were assessed by the coefficient of repeatability, coefficient of variation (CoV), intraclass correlation coefficient (ICC), and within-subject standard deviation (sw). RESULTS: Ninety-eight eyes from 98 KC patients were included. The sw of the IOP and bIOP did not exceed 1.1 mm Hg. A CoV less than 10% was found in all DCR parameters and had a good to excellent accordance regarding the ICC. The Corvis Biomechanical Index showed an excellent repeatability and interdevice reproducibility of 0.918 and 0.827, respectively. Also, the tomographic biomechanical index showed an excellent repeatability of 3 Corvis ST and Pentacam measurements (ICC = 0.997). With regard to keratoconic severity, a significant increase in the CoV was found between mild and moderate stages compared with the advanced stage. Nevertheless, it did not exceed 10% of the CoV in severe keratoconic eyes. CONCLUSION: Corvis ST measurements in keratoconic eyes were highly repeatable and reproducible.