Agreement of Total Keratometry and Posterior Keratometry Among IOLMaster 700, CASIA2, and Pentacam

PURPOSE: The purpose of this study was to compare total keratometry (TK) and posterior keratometry (PK) obtained by two swept-source optical biometers (IOLMaster 700 and CASIA2) and one Scheimpflug-based topography (Pentacam AXL). METHODS: The TK and PK in cataract surgery candidates obtained by IOLMaster 700, CASIA2, and Pentacam AXL were compared. Intraclass correlation coefficients (ICCs), limit of agreement, and Bland-Altman plots were used to assess the agreement. RESULTS: One hundred two patients with a mean age of 68.21 ± 8.70 years were included. There were significant differences among IOLMaster 700, CASIA2, and Pentacam AXL in the mean TK (TK(m)) (44.23 ± 1.59 diopters [D] vs. 43.25 ± 1.53 D vs. 43.94 ± 1.68 D; all P < 0.001), mean PK (PK(m); −5.90 ± 0.24 D vs. −6.25 ± 0.25 D vs. −6.37 ± 0.26 D; all P < 0.001) and TK-J0 (−0.34 ± 0.65 D vs. −0.23 ± 0.53 D vs. −0.12 ± 0.62 D; all P < 0.001). We also observed significant differences in PK-J45 between IOLMaster 700 and Pentacam AXL as well as between CASIA2 and Pentacam AXL (both P < 0.001). There was a good agreement in TK(m), TK-J0, TK-J45, and PK-J0 (ICC = 0.887, 0.880, 0.751, and 0.807, respectively), a moderate agreement in PK-J45 (ICC = 0.626), and a poor agreement in PK(m) (ICC = 0.498) among these 3 biometers. CONCLUSIONS: TK, PK, and the corresponding astigmatism obtained by IOLMaster 700, CASIA2, and Pentacam AXL showed significant differences, and could not be used interchangeably. TRANSLATIONAL RELEVANCE: Our study may help to guide preoperative keratometry measurement for intraocular lens (IOL) power calculation and astigmatism evaluation for patients with cataract.