Abstract
Purpose :
To evaluate changes in regional corneal epithelial thickness after corneal cross-linking using higher fluence (7.2 J/cm2) and accelerated treatment time (4 minutes) [A-CXL] in eyes with keratoconus using spectral-domain optical coherence tomography (SD-OCT) and to correlate focal epithelial and focal anterior curvature changes.
Methods :
Patients with keratoconus randomized to undergo A-CXL were prospectively measured using anterior segment SD-OCT (RTVue-100; Optovue, Inc., Fremont, CA) to compare regional corneal epithelial thickness and Scheimpflug imaging for focal axial curvature in eyes with keratoconus before and 1, 3, 6, and 12 months after accelerated CXL.
Results :
In total, 27 eyes from 20 patients were evaluated. Prior to A-CXL, epithelium was thinnest in the inferior inner and outer temporal regions, while 12 months postoperatively epithelium was significantly thinned in the outer nasal region by 3.2 μm, inner nasal by 3.2 μm, outer inferonasal by 3.4 μm, inner inferonasal by 1.4 μm, outer inferior by 1.8 μm, outer inferotemporal by 1.8 μm, and outer temporal by 1.1 μm (P < 0.05, all measurements), with no significant changes from 6 to 12-months. Epithelial thickness standard deviation across the central 6mm was significantly reduced by 3 months (1.4 μm, P = 0.09) and remained stable (reduced by 0.09 μm) at 1 year after A-CXL (P = .009). Change in epithelial thickness was poorly correlated to change in anterior curvature (r = -0.035) with wide variation between eyes.
Conclusions :
Significant epithelial remodeling occurs after accelerated CXL in eyes with keratoconus. The epithelium becomes thinner in pre-operatively thicker regions and more regular across the central 6mm of the cornea over the first 6 months after treatment, and stabilizes by 1 year. There was minimal overall correlation between focal epithelial thickness and anterior curvature changes, with wide variability. Establishing the pattern of epithelial remodeling after cross-linking may help optimize future customized treatment protocols.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.