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Repeatability of corneal layer thickness and vault measures from high resolution optical coherence tomography (OCT)
Session Title: Imaging I
Session Date/Time: Sunday 06/10/2013 | 14:30-16:00
Paper Time: 15:44
Venue: Elicium 1 (First Floor)
First Author: : A.Cervińo SPAIN
Co Author(s): : S. Garcķa-Lįzaro C. Albarran-Diego D. Madrid-Costa F. Pastor
To determine the intra- and interobserver repeatability of corneal layer thickness and vault measures determined manually from high resolution anterior segment OCT images.
Optometry Research Group Lab
Several corneal and phakic IOL images obtained from the HS-100 OCT (Canon Inc, Japan) were analyzed using external image analysis software (ImageJ, NIH, USA). Central thickness of corneal epithelium, Bowman’s layer and stroma were subjectively determined by 5 different experienced observers. Also, central, nasal, and temporal vault measures were obtained from in situ phakic IOL images. Three repeated measures were obtained from each image by each observer.
Coefficient of variation (COV) was less than 6% for intraobserver repeated measures of all parameters, and less than 9% between observers. Specifically, the best agreement between intraobserver repeated measures was for stromal thickness (0.2%) followed by Bowman’s layer thickness (0.5%), central vault (1,2%), epithelial thickness (3.2%), temporal vault (3.3%) and nasal vault (5,7%). Variation between mean values obtained by the different observers were lower for nasal vault (0.8%), followed by stromal thickness (1.3%), epithelial thickness (1.5%), temporal vault (2.9%), central vault (4.5%) and Bowman’s layer (8.1%)
Image quality provided by high resolution OCT systems allows repeatable subjective measures of ocular parameters. Differences between observers rely on the subjective interpretation of the boundaries between layers.