Early structural changes in keratoconic eyes after corneal cross-linking detected by polarisation sensitive optical coherence tomography

Session Details

Session Title: Cross-Linking

Session Date/Time: Tuesday 25/09/2018 | 14:00-16:00

Paper Time: 14:46

Venue: Room A3, Podium 3

First Author: : J.Lammer AUSTRIA

Co Author(s): :    F. Beer   N. Pircher   S. Holzer   M. Pircher   C. Hitzenberger   G. Schmidinger     

Abstract Details

Purpose:

To assess early structural changes in keratoconic corneas secondary to epi-off corneal crosslinking (CXL) using polarization sensitive optical coherence tomography (PS-OCT).

Setting:

General Hospital, Medical University of Vienna; Department of Ophthalmology and Optometry

Methods:

Thirty eyes of 30 subjects with bilateral keratoconus were imaged using conventional anterior segment (AS-)OCT and PS-OCT imaging. PS-OCT raster scanning was performed prior to as well as immediately after, 4 days and 1 month after CXL. Reflectivity images, as well as co-polarized, cross-polarized and retardation images of each visit were evaluated for structural changes. Findings were correlated with corresponding AS-OCT imaging.

Results:

At baseline, a homogenous depolarizing stromal signal was observed in the retardation image. 4 days after CXL a distinct delineation could be detected in the anterior stroma (43.2 ± 8.9% depth). One month after CXL all corneas presented a striking ring-shaped polarization preserving pattern. The pattern started at the peripheral anterior limits of the original CXL UV-A irradiation and reached the descemet’s layer in all cases but one (96.7%). Compared to corresponding AS-OCT images the ring-shaped patterns were found in the region of the demarcation line, however were less delineated and reached much deeper into the stroma.

Conclusions:

Using PS-OCT, tissue response to corneal crosslinking of keratoconic eyes was investigated in high detail, taking advantage of the polarizing properties of corneal tissue. Findings suggest a more profound restructuring not only in the anterior but also deep and posterior stroma after CXL than previously described in the literature. Such new morphologic signs might serve as future biomarkers to predict therapeutic outcomes or detect non-responders.

Financial Disclosure:

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