Changes in corneal epithelium-to-stroma ratio in patients with keratoconus without visual limitation

Session Details

Session Title: Corneal Biomechanics

Session Date/Time: Sunday 15/09/2019 | 16:30-18:00

Paper Time: 17:36

Venue: Free Paper Forum: Podium 4

First Author: : I.Toprak SPAIN

Co Author(s): :    A. Vega-Estrada   E. Esplá-Almodóvar   J. Alió                       

Abstract Details

Purpose:

To demonstrate association between changes in corneal epithelium and stroma using a high resolution anterior segment optical coherence tomography (AS-OCT) combined with placido disc system in patients with keratoconus (KC) with no or minimal visual limitation.

Setting:

Vissum Innovation, Alicante, Spain

Methods:

Fifty-five eyes (33 patients) diagnosed with keratoconus without or mild visual limitation and 59 control eyes (31 subjects) were included. Eyes with keratoconus were grouped as grade 0 (spectacle corrected visual acuity [CDVA] ≤ 0 logMAR, n= 28) and grade 1 (CDVA between 0.01 to 0.09 logMAR, n= 27) according to the visual limitation-based keratoconus severity system, which was previously validated. Epithelial and stromal thicknesses and epithelium/stroma thickness ratio (at the thinnest point, center, nasal, temporal, superior, inferior, superonasal, inferonasal, superotemporal, and inferotemporal quadrants) obtained from MS-39 AS-OCT (CSO, Firenze, Italy) were compared between the keratoconus and control groups.

Results:

Eyes with grade 0 KC had significantly thinner stroma and epithelium (thinnest point and inferotemporal quadrant), whereas higher nasal epithelium/stroma ratio when compared to the control eyes. Similarly, stromal (all) and epithelial thicknesses (at the center, superotemporal quadrant and thinnest location) values were significantly lower in eyes with grade 1 KC than in the control group, while epithelium/stroma ratio was higher in all quadrants. Comparing grade 0 and grade 1KC groups, stromal thicknesses at the center, thinnest location, nasal quadrants were significantly lower, whereas nasal epithelium/stroma ratio was higher in grade 1 KC group (p< 0.016 for all).

Conclusions:

Recent studies reported remarkable corneal epithelial thinning in KC in addition to stromal thinning. However, it is not clear whether corneal epithelium and stroma are altered equally in KC and corneal epithelium to stroma ratio was not reported up to date in early KC. The present study demonstrated decreased epithelial thickness and increased epithelium/stroma ratio in eyes with keratoconus with no or mild visual limitation compared to those of the healthy controls. In early KC, reduction in epithelial and stromal thicknesses seems not to be identical, since nasal epithelium/stroma thickness ratio tends to increase with KC progression.

Financial Disclosure:

None