Clinical SciencesObjective Screening Methods for Prior Refractive Surgery in Donor TissueOusley, Paula J. M.T.; Terry, Mark A. M.D.Author Information From the Lions Vision Research Laboratory of Oregon (P.J.O., M.A.T.) and Devers Eye Institute (M.A.T.), Portland, Oregon, U.S.A. Submitted April 18, 2001. Revision received September 27, 2001. Accepted October 3, 2001. This study was supported in part by the Oregon Lions Sight and Hearing Foundation, Portland, Oregon, U.S.A. Presented in part at the annual meeting of the Association for Research in Vision and Ophthalmology, Fort Lauderdale, Florida, U.S.A., May 3, 2000. The authors have no financial, commercial, or proprietary interest in any of the instruments or devices mentioned in this article. Address correspondence and reprint requests to Dr. M.A. Terry, Devers Eye Institute, 1040 NW 22nd Avenue, N200, Portland, OR 97210, U.S.A.; E-mail: firstname.lastname@example.org Cornea: March 2002 - Volume 21 - Issue 2 - p 181-188 Buy Abstract Purpose. Laser refractive surgery presents a growing contamination of the available corneal donor pool. There currently is no objective method for screening donor tissue for previous refractive surgery. We evaluated the usefulness of pachymetry and curvature maps in the screening of donor corneas. Methods. Pachymetry and curvature maps were generated from the Orbscan for 40 normal donor eyes. The average central pachymetry measurement was subtracted from the thinnest average midperipheral pachymetry measurement for each map to generate a normal range of pachymetry measurements. For curvature, the average curvature at the 3-mm zone was subtracted from the average curvature at the 7-mm zone to generate a normal range of corneal curvature. The pachymetry and curvature results from 10 donor eyes that had undergone refractive surgery were then compared with the normal range for each technique. Results. The average difference in pachymetry measurements between the midperipheral and central cornea for normal eyes was 0.040 ± 0.026 mm. Four of 10 corneas that had undergone refractive surgery were outside two standard deviations of this normal range. The average difference in corneal curvature between the 7-mm zone and the 3-mm zone for the healthy eyes was −0.2 ± 1.0 diopters. Four (40%) of 10 corneas that had undergone refractive surgery were identified with this method. When combined, the pachymetry and curvature methods detected seven (70%) of 10 corneas that had undergone refractive surgery. Conclusion. Regional differences in thickness and curvature in donor eyes may provide methods for screening for refractive surgery for myopia. Refinement in mathematical manipulations may further improve the sensitivity of these techniques. © 2002 Lippincott Williams & Wilkins, Inc.