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Lacey Haines, Olivera Kralj, Sebastian Marschall, Ahmed Gawish, Paul Fieguth, Neera Singal, Hall Chew, David Rootman, Allan Slomovic, Wendy Hatch, Kostadinka K Bizheva, Luigina Sorbara; Morphological corneal changes up to one year after crosslinking surgery with and without intracorneal ring segment insertion. Invest. Ophthalmol. Vis. Sci. 2019;60(9):6323.
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© ARVO (1962-2015); The Authors (2016-present)
Knowledge of morphological changes induced by crosslinking (CXL) and CXL plus intrastromal ring segment (CXL+ICRS) surgeries may help guide treatment decisions. This observational study investigates alterations in corneal shape during and after CXL treatments and identifies predictive factors.
64 eyes with keratoconus from 39 subjects were imaged with a Scheimpflug topographer prior to receiving CXL surgery and one year after. From this sample, 11 eyes that received CXL surgery and 8 eyes that received CXL+ICRS surgery were imaged with a research grade swept-source optical coherence tomographer (SS-OCT). The thicknesses of the cornea (TCT) and epithelial layer (ET) were acquired from SS-OCT images using custom processing software. The minimum corneal thickness (MCT) during surgery was measured using an ultrasound (US) pachymeter.
For CXL only, there was no significant difference between MCT from preoperative SS-OCT estimates and intraoperative US measurements (p>0.05). For CXL+ICRS, the preoperative SS-OCT MCT was significantly thinner than the US MCT (p=0.03). The mean ET did not change significantly one year after CXL only (p=0.82), but demonstrated a significant decrease of five microns for CXL+ICRS (p=0.01). For CXL only, baseline ET was predictive for changes in ET (R2=0.407,p= 0.029) and TCT (R2=0.364,p= 0.048), and age was significantly correlated with TCT changes at one year (R2=0.388,p= 0.048). For CXL+ICRS, age was predictive for changes in TCT at one year (R2=0.74,p= 0.006). There were no significant differences in the locations of the points of highest elevation, thinnest pachymetry or maximum curvature (p>0.05 for all) one year after CXL, however, individual data shows some eyes may experience clinically significant shifts.
Preoperative MCT estimates do not correlate well with intra-operative pachymetry measurements. Changes in ET and TCT are correlated with baseline ET and age. The locations of topographical features do not show large changes one year after surgery, although some individual corneas may demonstrate clinically significant modifications.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
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