Is epithelial thickness mapping a reliable tool in forme fruste keratoconus?

Session Details

Session Title: Moderated Poster Session: Cornea

Venue: Poster Village: Pod 1

First Author: : A.Swampillai UK

Co Author(s): :    K. O'Kane   N. Habib                    

Abstract Details

Purpose:

Epithelial thickness profile across the cornea and in the thinnest corneal zone has been claimed as a useful tool for the early diagnosis of corneal ectasia. Here we present five cases of form fruste keratoconus with near normal epithelial thickness mapping with optical coherence tomography (OCT).

Setting:

Royal Eye Infirmary, Plymouth, UK.

Methods:

Retrospective case review of five cases of established keratoconus in one eye with the form fruste condition in the other eye. All eyes were assessed using a rotating Scheimpflug camera (Pentacam) and a Fourier-domain OCT system (RTVue) utilising a “Pachymetry + Cpwr” corneal scan pattern (6mm diameter, 8 radials, 1024 axial-scans each repeated 5 times) centring on the pupil. Zonal epithelial thickness and other diagnostic variables, including pachymetry statistics (within 5mm zone) and epithelium statistics (within 5mm zone including superior-inferior, minimum-maximum, standard deviation) were analysed.

Results:

In all five patients, normal epithelial thickness was noted within the central 2mm zone (average 54 µm +/-1) in the form fruste corneas. Near normal epithelial thickness was also noted in the thinnest corneal zone (average 51-53 µ). In contrast to previous studies, the thinnest epithelial point was not found to be consistently located inferiorly.

Conclusions:

Epithelial thickness mapping in the thinnest corneal zone may not always be a reliable indicator of early form fruste keratoconus.

Financial Disclosure:

None