Comparability and repeatability of pachymetry in keratoconus using four noncontact techniques

• DOI: 10.4103/0301-4738.170987
• Publication Date: 2015-12-03T11:23:05Z
• Authors: Mukesh Kumar; Rohit Shetty; Chaitra Jayadev; Debarun Dutta
• Keywords: Scheimpflug principle; Repeatability; Corneal pachymetry

Purpose: To compare and determine the repeatability of central corneal thickness (CCT) measurements using four noncontact pachymetry instruments in eyes with keratoconus. Materials Methods: The CCT consecutive patients keratoconus was measured during a single visit swept source optical coherence tomography (SS-OCT, Casia SS-1000°CT, Tomey, Nagoya, Japan), rotating Scheimpflug camera system (Pentacam, Oculus Optikgerate GmbH, Wetzlar, Germany), scanning slit topographer (Orbscan IIz topography, Baush Lomb Surgical Inc., San Dimas, CA, USA), hand-held spectral domain OCT (HHSD-OCT, Bioptigen Durham, North Carolina, USA). Test-retest variability, correlation between interdevice agreement were analyzed. Results: Fifty 25 participants analyzed this study. All measurement methods correlated well each other (r > 0.9, P < 0.001). Mean ± standard deviation by HHSD-OCT, Orbscan IIz, SS-OCT, Pentacam 462 41 μm, 458 454 40 447 42 respectively. While HHSD-OCT over-estimated (P 0.001), there good obtained from three devices. However, numerical difference high trend seen all paired comparisons. Conclusions: Though different devices well, may be inadequate for their interchangeable use clinical practice.