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S. Hick, J.–F. Laliberté, J. Meunier, P.J. Ousley, M.A. Terry, I. Brunette; Objective screening for the detection of refractive surgery on donor corneas . Invest. Ophthalmol. Vis. Sci. 2004;45(13):4612.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose : Contamination of the donor pool by eyes with previous refractive surgery has become a major concern for eye banks worldwide. The aim of this study is to develop a sensitive, reliable, and rapid screening tool based on corneal topography to detect previous laser refractive surgery in donor corneas. Methods : 49 topographies (Orbscan II, Bausch & Lomb) were studied (Lions Vision Research Lab): 39 from unoperated donors and 10 from corneas with previous refractive surgery to correct myopia. Two screening algorithms for in–vivo detection of previous LASIK (Laliberté 2004) were used: VESm calculated the volume summation between the anterior surface and the best fit sphere for central and mi–peripheral zones, and DCm calculated the mean anterior tangential curvature difference between the central and mid–peripheral zones. Receiver operating characteristic (ROC) curves were obtained for each algorithm and sensitivity values at fixed specificities were calculated. For comparison purposes, 112 topographies from unoperated donors from the Quebec Eye Bank were also used. Results : For the ROC curve analysis, we obtained an area under the curve of 0.86 (Standard Error = 0.079) and 0.85 (SE = 0.080) for VESm and DCm, respectively. Both algorithms resulted in a sensitivity of 80% for a specificity set at 87%. The 2 false negatives had a very low correction (1.6 and 1.8 diopters of astigmatism). Development of screening algorithms for the detection of previous LASIK on donor eyes necessitates adaptation to the various degenerative changes affecting corneal shape and reflection after death, including epithelial damage, hypotony, and epithelial and stromal edema. It also needs to be robust to some degrees of decentration, in order to compensate for the absence of fixation of eye bank eyes at the time of topography. Conclusion: Criteria based on Orbscan II corneal topography are proposed for the screening of Eye Bank eyes for laser refractive surgery. Additional topographies from operated donor corneas are necessary to further improve the program.
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