Variability in corneal and epithelial pachymetry using optical coherence tomography machines in dry eye patients and contact lens wearers

Background Accurate evaluation of corneal and epithelial thickness is crucial for diagnosing and monitoring ocular surface disorders. This study compared the variability and agreement of corneal and epithelial thickness measurements obtained using two optical coherence tomography (OCT) devices – REVO FC 130 (Optopol Technology, Zawiercie, Poland) and RTVue XR Avanti (Optovue Inc. Fremont, CA, USA) – in patients with dry eye disease and long-term contact lens wearers.Research design and methods In this prospective, cross-sectional study, 67 participants (41 contact lens users and 26 with dry eye disease) underwent OCT imaging with both devices. Two trained operators performed at least three scans per eye. Main outcomes included intra-examiner repeatability, inter-examiner reproducibility, and inter-device agreement for epithelial, stromal, and pachymetric thicknesses, analyzed using Bland – Altman plots, Deming regression, and intraclass correlation coefficients (ICC).Results Both devices demonstrated high repeatability and reproducibility (ICC > 0.9) with minimal mean differences across all parameters. The REVO device provided slightly higher thickness values than the Avanti. Measurements in dry eye patients showed marginally lower consistency than in contact lens wearers.Conclusions Both OCTs deliver comparable, reliable corneal measurements, supporting their use interchangeably in clinical and research settings. Minor device-related variations should be acknowledged when assessing patients with ocular surface instability.