Assessment of central corneal thickness using optical coherence tomography

Purpose: To demonstrate the capability of model OCT3 optical coherence tomographer to evaluate central corneal thickness (CCT) in normal human corneas in vivo and compare the results with the those of standard ultrasound (US) pachymetry and Orbscan. Setting: New York Eye & Ear Infirmary Resident Clinic, New York, New York, USA. Methods: The CCT in 22 eyes of 11 subjects was determined with the OCT3 (Carl Zeiss Meditec), Orbscan (Bausch & Lomb, Inc.), and US pachymetry (DGH Technology, Inc.). Three central corneal scans of each eye were obtained using the OCT3. First, OCT3 data were processed using the standard OCT software program (OCT3(std)). Second, OCT3 raw data were exported and measurements were repeated using Scion Image for Windows program (OCT3(sci)). The OCT3 and Orbscan results were compared with the mean of 5 US pachymetry measurements in each eye. Results: The OCT3(std), OCT3(sci), and Orbscan CCT measurements showed high correlations with US pachymetry (r = 0.981, r = 0.984, and r = 0.942, respectively; P < .0001). Bland-Altman analysis showed a high level of agreement between US pachymetry and OCT3 techniques but not Orbscan. High repeatability for OCT3(std) (r(2) = 0.05) and OCT3(sci) (r(2) = 0.01) was also seen. Conclusion: Results show the OCT3 is an accurate, noninvasive, and reproducible technique for evaluation of CCT.