agreement among galilei, orbscan ii, and placido disk-based topography

purpose: to evaluate agreement between galilei, orbscan ii, and placido disk-based topography in terms of keratometry readings, and anterior and posterior elevation. methods: in this prospective comparative study, 184 eyes of 92 keratorefractive surgery candidates were evaluated with galilei, orbscan ii, and placido disk-based topography. keratometry readings and anterior and posterior elevation maps were compared using anova and paired t-test. results: mean keratometry reading by galilei, orbscan ii and corneal topography was 44.30±1.49 d, 44.11±1.47 d, and 44.60±1.56 d, respectively. the maximum difference in simk and astigmatism obtained three devices was less than 0.5 d with respect to the anterior and posterior best fitted sphere, the agreement between the galilei and orbscan ii was 0.96 and 0.95, respectively. maximum elevation of the anterior central cornea was 9.17±5.1 m by orbscan ii and 3.2±1.78 m by galilei. maximum depression of the posterior central cornea was 33.84±9.33 mm and 6.81±3.78 m, respectively. conclusion: despite a significant difference in mean keratometry readings, the three devices can be used as the difference in measurements was not clinically significant. however a large amount difference was found between galilei and orbscan ii interms of anterior and posterior maximum elevation values.