Purpose To assess the agreement and repeatability of horizontal visible iris diameter (HVID) or white-to-white (WTW) measurements between four imaging modalities; combination slit scanning elevation/Placido tomography, infrared biometry, dual rotating scheimpflug camera/Placido tomography, and swept source anterior segment optical coherence tomography (AS-OCT). Methods A prospective study of 35 right eyes of healthy volunteers were evaluated using the Orbscan IIz, IOL Master 700, Galilei G2, and DRI Triton OCT devices. The inter-device agreement and repeatability of HVID/WTW measurements for each device were analysed. Results Mean HVID/WTW values obtained by the Orbscan IIz, IOL Master 700, Galilei G2 and DRI Triton OCT were 11.77 ± 0.40 mm, 12.40 ± 0.43 mm, 12.25 ± 0.42 mm, and 12.42 ± 0.47 mm, respectively. All pairwise comparisons revealed statistically significant differences in mean HVID/WTW measurements (p = <0.01) except for the IOL Master 700—DRI OCT Triton pair (p = 0.56). Mean differences showed that the DRI Triton OCT produced the highest HVID/WTW values, followed by the IOL Master 700, Galilei G2 and Orbscan IIz, respectively. The limits of agreement were large on all device pairs. There was high repeatability for all devices (ICC ≥ 0.980). The highest repeatability was seen in the Galilei G2 (ICC = 0.995) and lowest in the Orbscan IIz (ICC = 0.980). Conclusions The four devices exhibit high repeatability, but should not be used interchangeably for HVID/WTW measurements in clinical practice.

The purpose of this study was to assess the repeatability and agreement of horizontal white-to-white (WTW) measurements using 4 different imaging modalities including a slit-scanning elevation topographer, dual rotating Scheimpflug camera and Placido Disc tomographer, Placido Disc topographer, and anterior segment optical coherence (OCT) tomographer. Methods:In this prospective study, 33 eyes of 33 healthy subjects were scanned 3 times using each of the Orbscan IIz, Sirius, Nidek OPD III, and DRI OCT Triton devices and WTW measurements were recorded. Repeatability was assessed using the intraclass correlation coefficient (ICC), and agreement was analyzed using Bland-Altman plots.

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