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. 2020 Apr 2;15(4):e0230589.
doi: 10.1371/journal.pone.0230589. eCollection 2020.

Reproducibility, and repeatability of corneal topography measured by Revo NX, Galilei G6 and Casia 2 in normal eyes

Adam Wylęgała  1   2 , Robert Mazur  1   2 , Bartłomiej Bolek  1   2 , Edward Wylęgała  1   2
Affiliations

Reproducibility, and repeatability of corneal topography measured by Revo NX, Galilei G6 and Casia 2 in normal eyes

Adam Wylęgała et al. PLoS One. .

Abstract

Purpose: To test the repeatability and reproducibility of the topography module in posterior segment spectral domain optical coherence tomography with Revo NX (new device) and to compare keratometry values obtained by a Scheimpflug tomography (Galilei G6) and a swept source OCT (Casia 2).

Methods: In this prospective study, healthy subjects with nonoperated eyes had their central corneal thickness (CCT), anterior and posterior K1/K2 corneal power measured with the new device. Two operators made 6 measurements on the new device to check intraobserver repeatability and reproducibility, and measurement on Casia 2 and Galilei G6. Bland-Altman plots were used to assess the agreement between the devices for each analyzed variable.

Results: 94 eyes (94 patients) were studied. All devices produced significantly different mean CCT, the highest for Galilei 569.13±37.58 μm followed by Casia 545.00 ±36.15 μm and Revo 537.39±35.92 μm. The mean anterior K1 was 43.21 ± 1.37 for Casia 2 43.21 ± 1.55 for Revo NX and 43.19 ± 1.39 for Galilei G6, and the differences were insignificant p = 0.617. The posterior K1 for Revo NX was -5.77 ± 0.25 whereas for Casia 2 it was -5.98±0.22 and for Galilei G6-6.09±0.28 D p< 0.0001. The Revo NX showed intraclass correlation coefficient ranging from 0.975 for the posterior K2 surface, and 0.994 for anterior K1 and 0.998 for CCT.

Conclusions: Revo NX is independent of the user and offers a high level of repeatability for the anterior and posterior cornea. The wide range of differences between the devices suggests they should not be used interchangeably.

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Conflict of interest statement

Optopol Technology Ltd. provided the Revo NX equipment with corneal topography module used in this study. AW received a speaker's honorarium form Carl Zeiss and works as a consultant for Carl Zeiss Meditec. Aw has a patent pending for the OCT angiography algorithm. Polish patent office P.418979. This does not alter our adherence to PLOS ONE policies on sharing data and materials.

Figures

Fig 1
Fig 1. Mean interoperator repeatability between operator A and B and reproducibility of Revo NX.
Fig 2
Fig 2. Bland-Altman plots showing the agreement between anterior K1 obtained by the Galileli G6.
Casia 2 and Revo NX and K2 in 94 normal eyes. The mean difference is represented by the solid blue line whereas the dotted lines represent±1.96 SD.
Fig 3
Fig 3. Bland-Altman plots showing the agreement between posterior K1 and K2 obtained by the Galileli G6 Casia 2 and Revo NX in 94 normal eyes.
The mean difference is represented by the solid blue line whereas the dotted lines represent ±1.96 SD.
Fig 4
Fig 4. Bland-Altman plots showing the agreement between central corneal thickness obtained by the Galileli G6.
Casia 2 and Revo NX in 94 normal eyes. The mean difference is represented by the solid blue line whereas the dotted lines represent ±1.96 SD.
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