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Yan Li, Omkar C Thaware, Winston Chamberlain, Afshan Nanji, John Clements, David Huang; OCT-Guided Laser Custom Corneal Collagen Cross-linking in Keratoconus. Invest. Ophthalmol. Vis. Sci. 2019;60(9):350. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
To report postoperative 6-month results of OCT-guided laser custom corneal collagen cross-linking (CXL) in keratoconus.
A commercial spectral-domain OCT (Avanti, Optovue) with a corneal adaptor module was used to map corneal and epithelial thicknesses. Keratoconic eyes with minimal corneal thickness more than 410 µm were considered for the laser custom CXL procedure. The procedure utilized myopic astigmatism treatment followed by hyperopic astigmatism treatment (Wavelight EX500 “wavefront-optimized” ablation, Alcon) to remove the epithelium and part of the Bowman’s layer and superficial stroma. Preoperative calculation used OCT pachymetry map and estimated ablation depth to ensure a minimum residual stromal thickness of more than 360 microns after laser ablation. Standard FDA-approved Avedro protocol was used for CXL treatment. Refraction, uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA), flat and steep simulated keratometry (SimK) readings were evaluated preoperatively and at a series of postoperative visits.
Eighteen eyes of 16 patients had the procedure and completed postoperative 6-month visits. The mean UDVA showed an improvement from 0.61 ± 0.33 logMAR preoperatively to 0.50 ± 0.37 logMAR (p=0.17) at 6-month follow-up. The mean CDVA improved from 0.16 ± 0.18 logMAR preoperatively to 0.12 ± 0.12 logMAR (p=0.35) postoperatively. A decrease in the mean spherical equivalent (SE) refraction was observed from -3.03 ± 3.45 diopters (D) prior to surgery to -2.74 ± 3.40 D (p=0.54) at the 6-month follow-up. The manifest cylinder significantly decreased from -2.83 ± 1.35 to -2.08 ± 1.42 (p=0.03) postoperatively. The mean steep and flat SimK readings decreased significantly from 49.3 ± 3.14 D and 46.3 ± 3.4 D preoperatively to 48.2 ± 2.7 (P=0.003) and 44.8 ± 2.9 D (P<0.0001) postoperatively.
Keratoconic eyes undergone OCT-guided laser custom CXL procedure demonstrated vision improvement at 6-month follow-up. Longer-term follow-up is needed to further evaluate the efficacy of the procedure.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
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