Corneal thickness measurements during corneal collagen cross-linking: comparability of 3 ultrasound pachymeters and swept-source OCT

Session Details

Session Title: Cross-Linking

Session Date/Time: Sunday 06/09/2015 | 08:00-09:30

Paper Time: 08:33

Venue: Main Auditorium

First Author: : J.Peeters THE NETHERLANDS

Co Author(s): :    M. Dickman   N. Visser   S. Gast   I. Saelens   T. Berendschot   R. Nuijts     

Abstract Details

Purpose:

To assess the comparability, correlation and agreement between 3 ultra-sound pachymeters (USP) and swept-source ocular coherence tomography (OCT) for central corneal thickness (CCT) measurement during corneal collagen cross-linking (CXL) for keratoconus. *7th co-author:A. Ayvaz, MD, University Eye Clinic Maastricht

Setting:

Prospective comparative study at University Eye Clinic Maastricht, Holland

Methods:

20 patients undergoing CXL for keratoconus were included. CCT was measured using 3 USP devices: 1. POCKET II, Quantel-Medical, 2. SP-100, Tomey, 3. DGH 555B-Pachette 4, DGH Technology and swept-source OCT: CASIA SS-1000, Tomey. USP and swept-source OCT measurements were performed prior to and immediately following CXL. Additional USP measurements were performed following epithelial abrasion, after Riboflavin administration, and after 10 and 20 minutes of ultra-violet A radiation. Linear Mixed Model (LMM) analysis was used to assess CCT comparability. Correlations were investigated by Pearson correlation analysis. Agreement was evaluated using Bland Altman plots for repeated measurements.

Results:

CCT measurements were comparable between USP devices, and between swept-source OCT and USP devices (F=0.538, P=0.627). Correlation between the USP devices, and between swept-source OCT and USP devices was high (r=0.937-0.942, p<0.001 ; r=0.810-0.857, p<0.001). Agreement between USP devices was highest between the POCKET II and SP-100 (mean=-2.8μm, LoA=-49.9-44.3μm) and lowest between the DGH-555B and SP-100 (mean=6.7μm, LoA=-42.9-56.2μm). Agreement between swept-source OCT and USP devices was highest between the CASIA SS-1000 and the SP-100 (mean=0.0μm, LoA=-79.0-79.0μm) and lowest between the CASIA SS-1000 and the POCKET II (mean=-6.5μm, LoA=-91.4-78.5μm).

Conclusions:

Mean CCT measurements between USP devices, and between swept-source OCT and USP devices are comparable and highly correlated in patients with keratoconus. However, agreement between USP devices, and between swept-source OCT and USP devices is low. This raises concerns regarding the interchangeability of these devices for CCT measurement during CXL.

Financial Interest:

NONE