Screening for Previous Refractive Surgery in Eye Bank Corneas by Using Optical Coherence Tomography

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.