Axial length measurements: Comparison of a new swept-source optical coherence tomography-based biometer and partial coherence interferometry in myopia

Purpose: To compare axial length (AL) measurements between a swept-source optical coherence tomography (SS-OCT) biometer (10LMaster 700) and a partial coherence interferometry (PCI) biometer (10LMaster, version 5.4) in myopic eyes. Setting: Severance Hospital, Yonsei University, Seoul, South Korea. Design: Prospective evaluation of a diagnostic test. Methods: This study enrolled patients with a diagnosis of myopia in their medical records. Two consecutive AL measurements were performed in each eye in random order using the 2 biometers. Sub analysis was performed according to lens status, fixation status, degree of myopia, and the presence of posterior staphyloma. The interdevice agreement was evaluated with Bland-Altman analyses and paired t tests. Results: This study comprised 219 eyes of 117 patients. During a fixation check using SS-OCT, 19.6% of eyes showed fixation loss. Overall, the SS-OCT biometer showed a longer AL than the PCI biometer. (P <.001) In a subanalysis that categorized eyes according to lens status, fixation status, degree of myopia, and the presence of posterior staphyloma, the SS-OCT biometer also showed longer ALs than the PCI biometer. Of eyes with good fixation, significant differences in AL measurements between devices were detected for those with posterior staphyloma (P <.001) but not for those without posterior staphyloma (P =.104). Conclusions: The 2 devices showed differences in AL measurements in myopic eyes. Fixation status and the presence of posterior staphyloma were important factors in these differences. For myopic eyes with posterior staphyloma, the SS-OCT biometer is expected to produce more precise AL measurements because it allows evaluation of the fixation status. (C) 2017 ASCRS and ESCRS