Screening for Previous Refractive Surgery in Eye Bank Corneas by Using Optical Coherence Tomography.
Lin, Roger C PhD; Li, Yan MS; Tang, Maolong PhD; McLain, Marcy CEBT; Rollins, Andrew M PhD; Izatt, Joseph A PhD; Huang, David MD, PhD
26(5):594-599, June 2007.
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Purpose: To use optical coherence tomography (OCT) to detect previous refractive surgery in donor corneas.
Methods: We constructed a tabletop OCT scanner operating at 1310-nm wavelength. Donor corneas at the Cleveland Eye Bank were scanned while sealed within the sterile container immersed in Optisol GS. OCT scanning was performed with 7.6-mm-long lines (512 axial scans) along 8 meridians. Anterior and posterior corneal surfaces were automatically mapped using image processing software that we developed. Curvature was computed from the best parabolic fit in the central 5-mm diameter. Layered analysis of the stromal reflectivity was also performed. Twenty-nine corneas from 19 donors were examined. Five had a history of laser in situ keratomileusis (LASIK).
Results: The flap interfaces could not be visualized on slit-lamp or OCT images but were confirmed by histology. The death-to-scan time was 22.1 /- 11.4 (SD) hours for normal corneas and 100.6 /- 57.5 hours for LASIK corneas. The anterior surface power was 67.5 /- 2.5 D in control corneas and 64.5 /- 2.4 D in LASIK corneas (P = 0.023). There was no significance between the 2 groups in terms of posterior curvature and thickness parameters. The anterior/posterior reflectivity ratio in the central 4-mm diameter was significantly lower in post-LASIK corneas than in control (P < 0.05).
Conclusions: OCT provides thickness, topography, and reflectivity maps of donor corneas without taking them out of preservation medium and container. The anterior curvature and the anterior/posterior stromal reflectivity ratio may be useful for detecting previous LASIK.
Copyright (C) 2007 Wolters Kluwer Health, Inc. All rights reserved.