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

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

Department of Ophthalmology of University Hospital Carl Gustav Carus, Dresden

This prospective repeatability analysis enrolled 43 normal and 57 KC eyes. 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.

The repeatability of anterior corneal parameters was comparable between RSC and SS-OCT in normal eyes (r<0.5D). Coefficient of repeatability (r) was increased in mild and moderate KC for all parameters using both devices. In moderate KC, r 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.