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. 2022 May 23;9(1):19.
doi: 10.1186/s40662-022-00290-6.

Comparison of corneal tomography using a novel swept-source optical coherence tomographer and rotating Scheimpflug system in normal and keratoconus eyes: repeatability and agreement analysis

Affiliations

Comparison of corneal tomography using a novel swept-source optical coherence tomographer and rotating Scheimpflug system in normal and keratoconus eyes: repeatability and agreement analysis

Robert Herber et al. Eye Vis (Lond). .

Abstract

Background: To determine the repeatability and agreement using corneal tomography of a swept-source optical coherence tomographer (SS-OCT) compared to a rotating Scheimpflug camera (RSC) in normal eyes and keratoconus (KC) eyes.

Methods: This prospective repeatability analysis was performed at the Department of Ophthalmology of University Hospital Carl Gustav Carus, Dresden, Germany. Forty-three normal and 57 KC eyes were enrolled in the study. Three consecutive measurements were performed by the same operator on each device. Corneal parameters of anterior and posterior corneal surface, such as simulated keratometry (SimK), as well as central and thinnest corneal thickness were evaluated. Repeatability and agreement were assessed by using the coefficient of repeatability and Bland-Altman analysis.

Results: The repeatability of anterior corneal parameters was comparable between RSC and SS-OCT in normal eyes (repeatability < 0.5 D). Repeatability was increased in mild and moderate KC for all parameters using both devices. In moderate KC, repeatability of Kmax was 1.33 D and 0.78 D for RSC and SS-OCT, respectively. Repeatability of posterior corneal parameters was consistently better for SS-OCT. Significant offsets and wide ranges of limits of agreement were found between the devices for SimK and corneal thickness values.

Conclusions: SS-OCT showed highly repeatable measurements of anterior and posterior corneal parameters in normal and KC eyes. Compared to RSC, the SS-OCT had a better repeatability of anterior corneal parameters in mild and moderate KC as well as posterior corneal parameters in all groups. Both devices should not be used interchangeably in the diagnostic process of patients. Trial registration NCT04251143 at Clinicaltrials.gov, registered on 12 March 2018, https://clinicaltrials.gov/ct2/show/NCT04251143?cond=Keratoconus&cntry=DE&city=Dresden&draw=2&rank=1.

Keywords: ANTERION; Cornea; Keratoconus; OCT; Pentacam; Scheimpflug; Swept-source; Tomography; Topography.

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Conflict of interest statement

All authors have no conflicts of interests to be declared. There are no financial interests to disclose.

Figures

Fig. 1
Fig. 1
Comparison of topography maps of RSC (left) and SS-OCT (right) of a keratoconus with corresponding Scheimpflug image (left) and OCT scan (right). Color scaling is set to 0.5 D
Fig. 2
Fig. 2
Bland-Altman plots of steep SimK (anterior), average SimK (anterior) of each subgroup
Fig. 3
Fig. 3
Bland-Altman plots of Kmax (anterior) of each subgroup
Fig. 4
Fig. 4
Bland-Altman plots of central corneal thickness (CCT), and minimal corneal thickness (MCT) of each subgroup

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