Agreement of post-LASIK corneal power and corneal thickness measurements by pentacam and GALILEi corneal tomography systems
Hsieh, Y.-H.; Weng, T.-H.; Chou, Y.-C.; Wu, K.-L.; Liang, C.-M.; Tai, M.-C.
Journal of the Chinese Medical Association Jcma 82(1): 72-77
ISSN/ISBN: 1728-7731 PMID: 30839408 DOI: 10.1016/j.jcma.2018.07.005
Post-LASIK corneal conditions cannot be accurately measured by traditional optometric approaches. Therefore, we aimed to analyze the agreement of two rotating Scheimpflug cameras in corneal assessment. Fifty otherwise healthy volunteers who had undergone LASIK were recruited in this study. The values of mean and central total corneal power (TCP), including TCP1, TCP2, and TCP-IOL, were measured by GALILEI Scheimpflug camera. The values of total corneal refractive power (TCRP) readings at both 2 mm ring and 3 and 4 mm zones were detected by Pentacam Scheimpflug camera. Central corneal thickness (CCT) and thinnest corneal thickness (TCT) were quantified by GALILEI and Pentacam respectively. Paired t-tests and Bland-Altman analyses were used to evaluate statistical differences between measurement results obtained by GALILEI and by Pentacam. Among these 50 subjects, the mean and central TCP1 values (37.31 ± 2.61 and 37.27 ± 2.64) derived from GALILEI measurements were consistent with the TCRP values (37.08 ± 2.76, 37.11 ± 2.74, and 37.19 ± 2.68; p > 0.05) determined by Pentacam at the 2 mm ring apex, 3 mm zone apex, and 4 mm zone apex. There were no statistically significant differences in central corneal thickness (CCT) values measured by the two cameras (463.64 ± 55.67 μm for GALILEI and 470.69 ± 44.04 μm for Pentacam, respectively; p > 0.05). However, the limits of agreement were wide when comparing mean TCP1 (-1.4 to 1.8 D, -1.4 to 1.8 D, and -1.3 to 1.6 D), central TCP1 (-1.2 to 1.6 D, -1.2 to 1.6 D, and -1.2 to 1.4 D) and CCT (-77.2-63.0 μm). Corneal power and corneal thickness are disparate post-LASIK evaluation parameters when comparing the utility of GALILEI with that of Pentacam.