CORNEA DONOR STUDY INVESTIGATOR GROUP FINDS PREOPERATIVE CELL DENSITY NOT A FACTOR IN SUCCESS
January 11, 2010
CLEVELAND - A new predictor of cornea transplant success has been identified by the Cornea Donor Study (CDS) Investigator Group. New analysis of data from the 2008 Specular Microscopy Ancillary Study (SMAS), a subset of the CDS, found that the preoperative donor cell count of endothelial cells, previously considered to be an important predictor of a successful transplant, did not correlate with graft success. Instead the study found that a patient's endothelial cell count six months post-cornea transplant is a better indicator of subsequent failure of the graft rather than the donor's cell count. These results offer an additional, reliable indicator of success that surgeons can use for monitoring patients at the six-month milestone after transplantation.
Endothelial cells form the back layer of the cornea and keep the cornea clear and prevent it from swelling. Previously it was thought that the more endothelial cells/mm2 in the donor cornea, the better, which put pressure on the eye banks to have donors with the highest count possible to distribute to corneal surgeons. However, the SMAS findings show no correlation between it and a patient's graft success rate five-years post transplant, as long as the industry standard minimum of 2,000 cells/mm2 was met. The results of this study are published in the January issue of the Archives of Ophthalmology.
"These new findings of the SMAS are excellent examples of evidence-based medicine impacting clinical practice," says Jonathan H. Lass, M.D., senior author of the study and Professor and Chair of the Department of Ophthalmology and Visual Sciences at Case Western Reserve University School of Medicine and University Hospitals Case Medical Center. "This evidence offers surgeons a broader pool of donors for their patients and will allow more individuals to donate to eye banks." The results were analyzed at the Specular Microscopy Reading Center, part of the Department of Ophthalmology and Visual Sciences at Case Western Reserve University and the University Hospitals Eye Institute.
Conceived in 1998, the CDS is a prospective cohort study that has already reported: 1) The age of the donor does not impact transplant survival after five years for conditions with moderate risk for graft failure due to endothelial dysfunction (Fuchs' dystrophy, pseudophakic/aphakic corneal edema) (Ophthalmology 2008); 2) Incompatibility of blood type between the donor and recipient also does not impact graft survival at five years (Am J Ophthalmology 2009); and 3) There was a trend toward greater endothelial cell loss (75%) in the older donor age group (over 65 years to 75 years of age) than the younger donor age group (under 65 years) (69%), but this difference did not impact graft survival at five years (Ophthalmology 2008. This NIH-funded study has been extended through 2012 in order to determine whether these findings persist for a total of ten years post-transplant.
"The more than 100 physicians and researchers involved in the Cornea Donor Study have been leading the effort to identify factors that will keep donated corneas clearer for longer," says Roy W. Beck, M.D., Ph.D., the principal investigator of the Cornea Donor Study Investigator Group and Executive Director of the Jaeb Center for Health Research in Tampa, Florida.
Additional support for CDS was provided by: Eye Bank Association of America, Bausch & Lomb, Inc., Tissue Banks International, Vision Share, Inc., San Diego Eye Bank, The Cornea Society, Katena Products, Inc., ViroMed Laboratories, Inc., Midwest Eye-Banks (Michigan Eye-Bank, Illinois Eye-Bank), Konan Medical Corporation, Eye Bank for Sight Restoration, SightLife, Sight Society of Northeastern New York (Lions Eye Bank of Albany), and Lions Eye Bank of Oregon.
Founded in 1843, Case Western Reserve University School of Medicine is the largest medical research institution in Ohio and is among the nation's top medical schools for research funding from the National Institutes of Health. The School of Medicine is recognized throughout the international medical community for outstanding achievements in teaching. The School's innovative and pioneering Western Reserve2 curriculum interweaves four themes--research and scholarship, clinical mastery, leadership, and civic professionalism--to prepare students for the practice of evidence-based medicine in the rapidly changing health care environment of the 21st century. Nine Nobel Laureates have been affiliated with the School of Medicine.
Annually, the School of Medicine trains more than 800 MD and MD/PhD students and ranks in the top 25 among U.S. research-oriented medical schools as designated by U.S. News & World Report's "Guide to Graduate Education."
The School of Medicine is affiliated with University Hospitals Cleveland Medical Center, MetroHealth Medical Center, the Louis Stokes Cleveland Department of Veterans Affairs Medical Center, and the Cleveland Clinic, with which it established the Cleveland Clinic Lerner College of Medicine of Case Western Reserve University in 2002. case.edu/medicine.