Comparison and reproducibility of corneal thickness and curvature readings obtained by the Galilei and the Orbscan II analysis systems

Abstract

Purpose To compare central corneal thickness (CCT) and keratometry readings using the Galilei dual Scheimpflug analyzer, the Orbscan II anterior segment analysis system, and the Sonogage ultrasound (US) pachymeter. Setting Lucerne Eye Clinic, Cantonal Hospital, Lucerne, Switzerland. Methods In a prospective single-center study, 85 eyes of 45 healthy volunteers were examined with the Orbscan II and Galilei systems in random order followed by Sonogage US pachymetry. The CCT and keratometry measurements were compared using a paired t test. To assess the intraobserver and interobserver reproducibility of the 2 keratometers, 9 volunteers were examined 3 times by 4 independent observers and the intraclass correlation coefficient (ICC) was calculated. Results The mean CCT was 551.7 μm ± 36.6 (SD) with the Galilei, 554.8 ± 45.1 μm with the Orbscan II, and 558.5 ± 38.4 μm with the Sonogage. The CCT readings of the Galilei and Orbscan II did not differ significantly (P = .12). The mean keratometry readings with the Galilei and Orbscan II were similar, although both the steep (Ks) and flat (Kf) axes tended to be flatter with the Galilei system. The ICCs for CCT, Kf, and Ks were high with both keratometers (0.98, 0.97, 0.84 for Galilei and 0.97, 0.96, 0.95 for Orbscan II, respectively), indicating that variation in measurements was mainly due to true subject-to-subject variation rather than observer error. Conclusion Keratometry and pachymetry readings with the Galilei and Orbscan II systems showed good concordance and high reproducibility, which would allow the examinations to be delegated to nonmedical personnel.