RESUMEN
PURPOSE: To evaluate the repeatability of a new swept source optical coherence tomography (SS-OCT) based biometer to measure anterior segment parameters, and to assess the agreement with three other imaging devices based on different measurements principles. SETTING: Unit of Eye and Vision, Department of Clinical Neuroscience, Karolinska Institutet, Sweden. DESIGN: Prospective, comparative case series. METHODS: 3 consecutive measuremetns were obtained in unoperated eyes with the Eyestar900 (SS-OCT), Lenstar 900, MS-39, and Sirius. The following anterior segment parameters were evaluated: central corneal thickness (CCT), corneal diameter (CD), aqueous depth (AQD), and corneal power metrics. The repeatability limit (Rlim), coefficient of variation (CoV), and a repeated measures Bland-Altman analysis were performed. RESULTS: 74 eyes of 74 participants were measured. The Rlims for CCT, CD, and AQD were lower than 10µm, 0.3mm, and 0.10mm for all devices, respectively. The corresponding CoVs for these parameters never exceeded 1.2%. The Rlim for the corneal power metrics never exceeded 0.60D for any of the instruments. Lenstar showed the best agreement with the MS-39 to measure CCT, CD, and AQD (limit of agreement interval, LoA: 15.54µm, 0.55mm, and 0.16mm, respectively). The mean difference for keratometry parameters was lower than 0.3D for all device comparisons, and the LoA interval ranged between 0.52D to 1.21D. CONCLUSIONS: The repeatability for measuring anterior segment parameters was good, and the agreement among all the instuments was good for CD and AQD measurements. However, for CCT and keratometer parameters, the instruments cannot be used interchangeably due to large LoA interval.
