Precision (Repeatability And Reproducibility) Of The Pentacam Hr Tomographer Across A Range Of Measurement Parameters, Obtained With Two Different Scan Protocols: “50-Cornea Fine” And “25-3D Scan”, In Patients With Keratoconus

Published 2022 - 40th Congress of the ESCRS

Reference: PO296 | Type: Free paper | DOI: 10.82333/c6sp-hd57

Authors: Davide Romano* ¹ , Giulia Coco ² , Alfredo Borgia ³ , Stephen B Kaye ⁴ , Francesco Semeraro ¹ , Vito Romano ¹

¹University of Brescia,Brescia,Italy, ²University of Rome "Tor Vergata",Italy,Italy, ³Humanitas University,Milan,Italy, ⁴Royal Liverpool University Hospital,Liverpool,United Kingdom

Purpose

To evaluate the precision (repeatability and reproducibility) of the Pentacam HR (high-resolution) tomographer (Oculus, Wetzlar, Germany) across a range of measurement parameters, obtained with two different scan protocols: “50-Cornea Fine” and “25-3D Scan”, in patients with keratoconus

Setting

Eye Clinic- University of Brescia and St.Paul's Eye Unit - Royal Liverpool University Hospital

Methods

51 eyes of 51 patients had three consecutive measurements of both the (25) 3D-scan mode and the (50). Randomly, either the (25) 3D-scan or the (50) Cornea fine scan was taken first.

Investigated parameters included anterior maximal keratometry reading (Kmax) anterior standard keratometry (K) readings (K1 and K2), anterior and posterior average K reading (Km), anterior and posterior astigmatism and associated axis, thinnest corneal thickness (TCT), anterior ectasia, posterior ectasia, index of surface variance (ISV) and index of vertical asymmetry (IVA).

Results

Intraclass Correlation Coefficient with relative 95% CI for each measurement analysed with both (25) 3D-scan and (50) Cornea fine modes. Overall, both scans showed excellent repeatability with almost all ICC > 0.9. Worst repeatability was found in anterior and posterior astigmatic axes and posterior astigmatism, however still showing good values ( > 0.8).

The cornea fine scan provided the most repeatable measurements for the anterior cornea, except for Kmax, where the 25-picture scan proved better repeatability for posterior corneal surface. TCT, ISV and IVA values were more repeatable with the (50) cornea fine scan mode.

Conclusions

Measurements taken with the Pentacam HR are repeatable and reproducible in patient with keratoconus in both 50-cornea fine and 25-3D scans. However, having the opportunity to chose one, 50-cornea fine should be preferred. This is in view of the major repeatability and reproducibility in evaluating the anterior cornea surface, IVA, ISV, TCT.