Comparison between Pentacam-HR and optical coherence tomographycentral corneal thickness measurements in healthy feline eyes.

Objectives: To measure the central corneal thickness (CCT) in healthy feline eyes with Scheimpflug imaging (Pentacam, Pentacam(®) -HR) and to compare these values with those obtained with spectral-domain optical coherence tomography (OCT, Optovue(®) iVue).

Animals Studied: Thirty one sedated Domestic Short-haired cats.

Procedures: Two repeated CCT measurements were obtained from both eyes using Pentacam measured at the pupil center and corneal apex (CCTpupil and CCTapex ) and using SD-OCT (CCTOCT ). Agreement between the imaging modalities for CCT and intradevice repeatability was evaluated with Bland-Altman analysis. Mixed modeling was used to test for a difference between methods.

Results: The calculated mean ± SD CCT was CCTOCT  = 584.93 ± 39.05 μm, CCTpupil  = 608.25 ± 47.26 μm, and CCTapex  = 606.41 ± 44.18 μm. There was a statistically significant difference between CCTOCT vs. CCTpupil (P < 0.0007) and CCTOCT vs. CCTapex (P < 0.0003) (n = 59 eyes). The 95% limits of agreement (LoA) for CCTOCT vs. CCTpupil was (-89.57 μm, 40.04 μm) and for CCTOCT vs. CCTapex was (-79.62 μm, 33.79 μm) (n = 59 eyes). 95% LoA between repeated CCT measurements by SD-OCT was (-10.23 μm, 9.32 μm) and by Pentacam was (-22.66 μm, 18.30 μm) at pupil and (-15.81 μm, 16.17 μm) at corneal apex (n = 11 eyes).

Conclusions: SD-OCT and Pentacam provide excellent CCT measurement repeatability. Pentacamapex is our recommended clinical setting for use of the Pentacam. The level of agreement between SD-OCT and Pentacam for CCT is good.