Within-session and between-session repeatability of corneal thickness in patients with endothelial disease

Session Details

Session Title: Cornea: Medical

Session Date/Time: Tuesday 10/10/2017 | 08:00-10:30

Paper Time: 09:06

Venue: Room 3.6

First Author: : F.Arnalich SPAIN

Co Author(s): :    C. Auladell   A. Couceiro                 

Abstract Details

Purpose:

To determine repeatability within-session and reproducibility between-sessions of apex and thinnest corneal thickness measurements using two noncontact pachymetry instruments based on Scheimplug system (Pentacam) and Swept Source Fourier Domain OCT (Casia S-100) in patients with corneal endothelial disease.

Setting:

Cornea Unit. Hospital Universitario Ramón y Cajal, Madrid, Spain

Methods:

For the purpose of this research, Pentacam and Casia OCT were used. Twenty-five normal subjects (35 eyes), 40 Fuchs dystrophy subjects with (23 eyes) or without corneal edema (38 eyes), 15 DSAEK patients (22 eyes) and 20 DMEK patients (29 eyes) were examined by a single operator. Subjects took part in two testing sessions, separated by a two-week break. During each session, three sets of measurements were taken for each subject. Statistical analysis was performed with STATA software. Within-session and between-sessions agreement tests were applied: repeatability and reproducibility coefficients, intraclass correlation coefficients, coefficient of variation, and 95% limits of agreement.

Results:

Precision of corneal thickness measurements was best for normal, Fuchs dystrophy without edema and DMEK for each measured point and with any of the instruments, while Fuchs dystrophy with edema had the worst precision. Casia measurements, specifically apex corneal thickness, had the best repeatability within-session and reproducibility between-sessions, significantly better than measurements taken with the Pentacam. The within-session and between-sessions coefficient variation with the Casia was < 0,4 % and < 1.2 % respectively. The within-session and between-sessions coefficient of variation with Pentacam ranged from 0.8 to 1.2 %, and from 1.3 to 2.7 % respectively depending on the group.

Conclusions:

Swept source fourier domain OCT is clinically more precise than Pentacam in order to evaluate changes in corneal thickness during follow up of corneal endothelial disease patients. Between-examination differences in thickness measurements during follow up of these patients should be interpreted differently depending on the instrument used to measure corneal thickness and the clinical status of the patient.

Financial Disclosure:

NONE