Repeatability and agreement of a new anterior segment optical coherence tomography with standard devices in normal, keratoconus, and post-refractive eyes

Purpose: To assess repeatability and agreement of Eyestar 900 (Haag-Streit, Köniz, Switzerland) with Pentacam AXL Wave system (Oculus, Wetzlar, Germany), Anterion (Heidelberg Engineering GmBH, Heidelberg, Germany), and MS-39 (CSO, Florence, Italy) in measuring anterior segment parameters. Methods: Two hundred normal eyes, 50 keratoconus (KC) eyes, and 50 post-refractive surgery eyes underwent three sequential scans on each instrument. The order of scans was randomized. Repeatability was assessed using within-subject standard deviation (Sw) and intraclass correlation coefficient (ICC). Bland-Altman analysis was used to assess the 95% limits of agreement. Results: Eyestar 900 had comparable repeatability to Anterion and MS-39 across groups. ICC was overall >0.8. Pentacam AXL Wave had lower Sw (better repeatability) across all groups. In normal eyes, Eyestar 900 can be used interchangeably with MS-39 and Anterion (P > 0.23). Eyestar 900 and Pentacam AXL Wave did not show agreement on any parameter, except anterior chamber depth (ACD) (P = 0.92). Eyestar 900 in KC eyes can be used interchangeably with MS-39, except for posterior keratometry (pK) and thinnest corneal thickness (TCT) (P < 0.001), and with Anterion, except for TCT and ACD (P < 0.001). In post-refractive eyes, Eyestar 900 can be used interchangeably with MS-39, except for pK (P < 0.001), and with Anterion, except for ACD (P < 0.001). Pentacam AXL Wave and Eyestar 900 cannot be used interchangeably in KC and post-refractive eyes. Conclusions: Newer devices such as Eyestar 900 can be used interchangeably with Anterion and MS-39 in normal eyes and partly in KC and post-refractive eyes. Pentacam AXL Wave and Eyestar 900 cannot be used interchangeably across the various groups. However, these multifunctional hybrid tools of combined topography, AS-OCT, can be helpful in refractive clinics.