A new imaging tool is helping us understand the healing response after corneal collagen crosslinking (CXL) in keratoconic patients, according to a study presented at ARVO. Investigators from the University of Vienna used polarization-sensitive optical coherence tomography (PS-OCT), which is better than conventional OCT at distinguishing individual tissues, to capture early changes after CXL. The polarizing properties of corneal tissue allowed PS-OCT to image individual corneal layers with greater contrast so that the effects in each could be seen more clearly.

The study included 30 patients with bilateral keratoconus who underwent both conventional anterior segment OCT (AS-OCT) and PS-OCT. Scans were done immediately after epi-off CXL, at day four and again at one month.

Researchers found greater restructuring not only in the anterior but also in the deep posterior stroma after CXL when imaging with PS-OCT. In all cases but one, the CXL effect reached Descemet’s membrane. These findings could serve as future biomarkers to predict therapeutic outcomes or detect non-responders, the investigators concluded.

By providing more detail than what’s currently available with conventional OCT, this technology may someday serve as predictor for expected responses with CXL, says Joseph Shovlin, OD, of Scranton, PA. “More detail of the morphologic changes following this procedure may help us understand who might have the best long-term desired effect in stabilizing this non-inflammatory thinning disorder.”

Lammer J, Beer F, Pircher N, et al. Early structural changes in keratoconic eyes after corneal crosslinking detected by polarization sensitive optical coherence tomography. ARVO 2018. Abstract 3435.