OCT-derived 3-D epithelial thickness distribution: comparative variability study in healthy and keratoconic eyes

Session Details

Session Title: Presented Poster Session 23: Refractive Surgery New Techniques / Instrumentation / Devices 2

Session Date/Time: Tuesday 16/09/2014 | 15:00-17:00

Paper Time: 16:00

Venue: Pod 2 (Poster Village)

First Author: : G.Pamel GREECE

Co Author(s): :    G. Asimellis   A. Kanellopoulos   C. Karabatsas        

Abstract Details

Purpose:

To evaluate repeatability, accuracy and precision, as well as the clinical feasibility of in vivo measurement of epithelial thickness and epithelial topographic variability in a large cohort of healthy and keratoconic eyes by spectral domain optical coherence tomography (AS-OCT), and to compare with Scheimpflug imaging keratoconus severity.

Setting:

Laservision.gr Eye Institute, Athens, Greece

Methods:

250 healthy (group-A) and 155 untreated keratoconic (group-Β) eyes were subjected to anterior segment OCT three-dimensional epithelial thickness imaging. Comparative statistical analysis of patterns was performed, investigating central, minimum, inferior, posterior, and topographic variability of epithelial thickness. Epithelial thickness characteristics were correlated to established Scheimpflug imaging–derived keratoconus classification and anterior surface irregularity indices.

Results:

Intra-individual repeatability of epithelial thickness was for group A ±1.13 μm, for group B ±1.78 μm for center and average ±1.67 μm (center, superior, inferior, maximum and minimum). In group A, center epithelial was 52.54±3.23 μm, maximum 55.33±3.27 μm and minimum 48.50±3.98 μm. In group B, center thickness was 51.75±7.02 μm, maximum and minimum were 63.54±8.85 μm and 40.73±8.51 μm. Topographic variability was 6.07±3.55 μm (range -22.81±12.55 μm) for the keratoconic group, while for the control group 1.59±0.79 μm (-6.86±3.33 μm). Both epithelial thickness variability and range were increased with keratoconus severity and correlated well with keratoconus severity.

Conclusions:

AS-OCT epithelial thickness measurement in keratoconus had high predictability. Compared to normal, particularly in lower stages of keratoconus, increased topographic thickness variability and range correlated remarkably with keratoconus severity, obtained by established Scheimpflug imaging-derived anterior-surface irregularity indices.

Financial Interest:

One or more of the authors... travel has been funded, fully or partially, by a company producing, developing or supplying the product or procedure presented