2M.D Professor, Turgut Ozal University Faculty of Medicine, Department of Ophthalmology, Ankara/TURKEY
3M.D, Kayseri Training and Research Hospital, Eye Clinic, Kayseri/TURKEY
4M.D, Turgut Ozal University Faculty of Medicine, Department of Ophthalmology, Ankara/TURKEY Purpose: To compare the central corneal thickness (CCT) measurements of three different devices.
Material and Methods: CCT was measured in one eye of 41 healthy subjects (age: 29.6±7.23 range:20-47), using the Nidek AL-Scan, Galilei G4 Dual Scheimpflug Analyzer and Cirrus HD-OCT (Cirrus Version 6.0). The agreement between the measurements of three devices was assesed using the one way ANOVA test. To assess the interexaminer reproducibility, two different examiners consecutively obtained CCT measurements in 23 eyes with Nidek AL-Scan, Galilei Dual Scheimpflug Analyzer and Cirrus HD-OCT.
Results: Mean±SD values for CCT using the Nidek AL-Scan, Galilei Dual Scheimpflug Analyzer and Cirrus HD-OCT were 541.04±34.91 μm, 541.56±31.05 μm, and 541.73±33.83 µm respectively. There was no statistically significant difference between these three devices at measuring CCT (p=0.98). Intraclass correlation between different observers was fine (>0.9 for each device) and Bland Altman plots of observers' measurements with each device showed good agreement.
Conclusions: Nidek AL-Scan, Galilei G4 Dual Scheimpflug Analyzer and Cirrus HD-OCT provide CCT measurements that are in agreement with each other and with the published values for CCT in human subjects. CCT measures from these instruments should be used interchangeably.
Keywords : Central corneal thickness, optical biometer, scheimpflug camera, optical coherence tomography