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C. E. Wheeldon, R. L. Niederer, C. N. J. McGhee; Comparison of Central Corneal Thickness Measurements by Pentacam, Orbscan II, Visante Anterior Segment Optical Coherence Tomography, and Ultrasound Pachymetry. Invest. Ophthalmol. Vis. Sci. 2009;50(13):5098.
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© ARVO (1962-2015); The Authors (2016-present)
To compare central corneal thickness (CCT) measurements in normal subjects obtained by four different
Pentacam rotating Scheimpflug camera, Visante anterior segment optical coherence tomography (ASOCT), Orbscan II, and ultrasound pachymetry (USP).Methods: Prospective study. Fifty normal subjects (100 eyes) underwent sequential measurements in CCT by Pentacam, ASOCT, Orbscan II (acoustic equivalent correction factor 0.89), and USP by a single experienced examiner. Data was analysed using the paired sample t test, and Bland Altman plots.
The mean age of subjects was 38 ± 12.1 years (mean ± standard deviation [SD]) (range 21 - 60 years). Mean measurements of CCT by Pentacam, ASOCT, Orbscan II, and USP were 553.7 ± 37.0µm (mean ± SD), 525.2 ± 38.3 µm, 559.2 ± 40.6 µm, and 541.4 ± 39.1 µm respectively. Measurements between the 4 modalities were strongly correlated (Pearson correlation r value >0.95). There was a statistically significant difference between the measurements obtained in CCT by all 4 methods (p<0.0001). Compared to USP, Pentacam and Orbscan II significantly overestimated CCT by a mean of 12.33 ± 1.81µm (mean ± SD), and 17.80 ± 2.37µm respectively while ASOCT underestimated it by 16.16 ± 1.79 µm.
Measurements in CCT obtained in clinical practice by these four different methods are not directly interchangeably and should be used with caution.
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