Relationship between repeatability in corneal topography parameters and increased disease severity in keratoconic eyes

Session Details

Session Title: Keratoconus and Phakic IOLs

Session Date/Time: Monday 12/09/2016 | 16:30-18:30

Paper Time: 17:18

Venue: Hall C4

First Author: : C.Bergin SWITZERLAND

Co Author(s): :    F. Majo   I. Guber                 

Abstract Details

Purpose:

Good repeatability of topographic measurements has been demonstrated in normal eyes but a clinically significant reduction in repeatability has been recently identified in keratoconic eyes. The aim of this study was to evaluate the relationship between repeatability and disease severity in keratoconic eyes measured by the Pentacam HR® device and to identify the best performing parameters in each disease stage.

Setting:

Intra-instrument repeatability assessment study in corneal and refractive surgery unit of the Jules-Gonin Eye Hospital, Switzerland

Methods:

Two hundred and forty eight keratoconic eyes of 197 patients were identified. All available images were exported automatically from the Pentacam HR device. Two good quality images taken on the same day within the same sitting were extracted and the repeatability between these two measures was assessed. The strength of the correlation between disease severity and repeatability was examined. Intereye correlations were corrected for with analysis of variance.

Results:

Mean age was 35.3 years, average maximal corneal curvature (K-max) was 55.3D, mean minimum pachymetry (TCT) was 458m. Mean repeatability(r) of K-max was 0.7D, 1.3D, 1.8D and 2.4D for topographic keratoconus classification (TKC) grade 1, 2, 3 and 4 respectively. A highly significant relationship between K-max and repeatability was observed, p<0.001. In TKC grade 1-4, the location of TCT was more repeatable than in healthy eyes. The relative utility values indicate that astigmatism and the Belin Ambrosia score will be best placed to distinguish new cases of keratoconus (TKC1), while the anterior corneal curvature parameters will be best placed to distinguish disease progression.

Conclusions:

The results of the present study suggest that progression will be more difficult to detect accurately using topographic measures in patients with high corneal curvature and/or more advanced keratoconus disease. In this study those parameters with the best repeatability were isolated for each stage of keratoconus in order to identify the corneal parameters which potentially detect disease progression most reliably.

Financial Disclosure:

NONE