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Measurement of central corneal thickness by high‐resolution Scheimpflug imaging, Fourier‐domain optical coherence tomography and ultrasound pachymetry
Author(s) -
Chen Shihao,
Huang Jinhai,
Wen Daizong,
Chen Wuhe,
Huang David,
Wang Qinmei
Publication year - 2012
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.2010.01947.x
Subject(s) - scheimpflug principle , repeatability , reproducibility , optical coherence tomography , fourier domain , ultrasound , optics , coefficient of variation , corneal pachymetry , ophthalmology , medicine , biomedical engineering , mathematics , cornea , corneal topography , physics , radiology , statistics
Abstract. Purpose: To compare the repeatability and reproducibility of central corneal thickness (CCT) measurements by high‐resolution (HR) rotating Scheimpflug imaging and Fourier‐domain optical coherence tomography (FD‐OCT). CCT measurements were compared to those determined by ultrasound pachymetry (UP). Methods: In 35 healthy eyes, intra‐observer repeatability for HR Scheimpflug (Pentacam) and FD‐OCT (RTVue) systems was determined in consecutive images taken by an observer in the shortest time possible. Imaging was repeated again by a second observer to evaluate inter‐observer reproducibility. The CCT measurements were compared among Scheimpflug, FD‐OCT and UP images. Results: Mean coefficients of repeatability were 0.48% for Scheimpflug and 0.26% for FD‐OCT. For Scheimpflug, the coefficient of inter‐operator reproducibility was 0.87%. For FD‐OCT, the coefficient of inter‐operator reproducibility was 0.45%. The CCT measurements by Scheimpflug, OCT and UP images were (mean ± standard deviation) 521.7 ± 27.6 μm, 510.8 ± 28.6 μm and 516.5 ± 27.6 μm, respectively. The differences between instruments were statistically significant. The 95% limits of agreement in CCT were −0.7 to 22.5 μm for Pentacam‐OCT, −13.4 to 24.0 μm for Pentacam‐UP and −26.7 to 15.4 μm for OCT‐UP. There was a high degree of correlation between CCT measured by all 3 methods. Conclusion: Noncontact measurements of CCT with HR Scheimpflug and FD‐OCT systems yielded excellent repeatability and reproducibility and can be used interchangeably. Although both devices were comparable with UP; in clinical practice, the measurements acquired by optical modalities are not directly interchangeable with UP measurements.