Posters

Corneal epithelial thickness intrasubject repeatability and its relation with visual limitation in keratoconus

Poster Details

First Author: M.Mimouni ISRAEL

Co Author(s): A. Vega-Estrada   E. Espla   J. Alio              

Abstract Details

Purpose:

To evaluate intra-subject repeatability of anterior segment optical coherence tomography (AS-OCT) combined with placido disc MS-39 (CSO, Firenze, Italy) and assesses the correlation between epithelial thickness measurements and the degree of visual limitation in keratoconus patients.

Setting:

Vissum Institute of Ophthalmology, Alicante, Spain.

Methods:

This prospective, observational study, included eyes of keratoconus patients and volunteers serving as controls. Three repeated consecutive measurements were taken by the same experienced examiner. The central 3.0 mm and the nasal, temporal, superior, and inferior regions at 3.0-6.0 mm and 6.0-8.0 mm epithelial thickness indices were collected and correlated to the degree of corrected visual acuity (BCVA). Intra-subject repeatability of epithelial indices was assessed. The superior-inferior ratio was calculated by dividing the epithelial thickness at the superior and inferior regions.

Results:

This study included 167 eyes (n=89) of which 107 were keratoconus (n=58) and 60 were normal (n=31). Intraclass correlation coefficient was ≥ 0.90 for all measurements indicating high repeatabilty in keratoconus and normals. In multivariate analysis, associated with worse BCVA were thinner 3mm-central (p=0.04), thicker 8mm-superior (p<0.001) and thinner 8mm-inferior (p<0.001). Central 3mm decreased as keratoconus grading increased (p=0.002). Superior-inferior ratio at 8mm increased as keratoconus grading increased (p<0.001). In multivariate analysis thinner 3mm-central (R2=6.19%,p=0.04), greater superior-inferior 8mm ratio (R2=8.37%,p=0.004), greater superior-inferior 6mm ratio (R2=2.67%,p=0.02), and steeper K2 (R2 =21.51%,p<0.001) were associated with keratoconus (AUC=0.92).

Conclusions:

High repeatability of epithelial thickness measurements may be achieved in both keratoconus and healthy eyes with the MS-39. There is a significant correlation between epithelial thickness measurements and BCVA. These measurements may be of additional value in discriminating between keratoconus and healthy eyes.

Financial Disclosure:

None