Goal is to guarantee supply meets future demand
Researchers at Case Western Reserve University School of Medicine will lead a national study determining if corneas transplanted up to two weeks after donor death work as well as corneas transplanted up to one week after donor death. The National Eye Institute has awarded a $12.3 million grant to support the work.
The supply of donated corneas nationwide meets current needs - about 40,000 transplants in 2010.
But with an aging population and health concerns about the future donor pool, researchers want to ensure the supply can meet an expected growth in demand over the next two to three decades.
"Over the past 20 years, corneal transplant specialists have gotten comfortable using corneas up to one week after the death of the donor, when in fact they can use them up to two weeks after death," said Dr. Jonathan Lass, the Charles I Thomas Professor and Chairman of the Case Western Reserve Department of Ophthalmology and Visual Sciences and Director of the University Hospitals Eye Institute. Lass, who is also medical director of the Cleveland Eye Bank, which provides corneas for transplant, is the lead investigator of the Cornea Preservation Time Study.
The kickoff meeting for investigators and eye banks participating in the Cornea Preservation Time Study will be held prior to the American Academy of Ophthalmology Convention in Orlando, Friday, Oct. 21 at the Cornea Society/Eye Bank Association of America Fall Symposium.
"The Cornea Preservation Time Study is a model for the type of research we must continue to pursue in order to creatively target critical issues such as donor organ shortages," said Pamela B. Davis, MD PhD, dean of the CWRU School of Medicine.
"This project offers the potential of immediate, life-altering impact for thousands of people."
The U.S. Food and Drug administration does permit corneas to be stored in preservation medium at refrigerator temperature up to two weeks after donor death. And the excess supply of donated corneas in the U.S. - about 20 percent annually - are shipped overseas where they are successfully transplanted more than a week after donation.
But there has been limited follow-up.
To convince U.S. corneal surgeons to change from their regular practice, successful transplantation in the second week needs to be proved, Lass said.
The result of doubling the window for corneal transplants will increase the pool of donated corneas and improve public health and safety, he said.
Patients who need corneal transplants are typically 50 and older. According to projections by the U.S. Census Bureau, that population will grow from about 99 million in 2010 to about 133 million by 2030 in this country.
While the number of patients will grow the number of potential donors is waning.
"All of these issues disqualify potential donors: food contamination, such as mad cow disease and the recent listeria outbreak in cantaloupe; the growing number and spread of infectious diseases such as HIV and West Nile virus and the tropical disease chikungunya, which have no cure; high-risk behaviors such as methamphetamine use - which is at epidemic levels in some parts of the country - IV drug use and imprisonment; the growing number of people diagnosed with Alzheimer's or other neurologic diseases of unknown origin; and the aging population itself, which is less suited to donate because corneas age and deteriorate;" explained Dr. Marian Macsai, a professor of ophthalmology at the University of Chicago and chair of the Eye Bank Association of America. "Add them up and you've got a shrinking donor pool."
In addition to fewer donors to rely on, the growing list of disqualifiers requires greater scrutiny of the sources, Lass said. "We need more time to analyze the donor and test blood to ensure the safety of the recipient and quality of the cornea he or she receives."
The five-year study will be conducted at university-based, including University Hospitals Case Medical Center, and private clinics across the U.S. Leading institutions include Case Western Reserve School of Medicine's Vision Research Coordinating Center and Cornea Image Analysis Reading Center, in Cleveland, and the Jaeb Center for Health Research, in Tampa, Fla.
Researchers will compare the outcomes of 1,330 corneal transplants. Half the patients will receive transplants within 7 days of donor death, half within 8 to 14 days.
People suffering from diseases affecting the corneal endothelium, the critical back cell layer of the cornea that keeps the cornea from swelling, including Fuchs' Endothelial Corneal Dystrophy, an age-related disease that may be inherited; and pseudophakic/aphakic corneal edema, a complication following cataract surgery, will be enrolled.
All patients will undergo a corneal transplant called an endothelial keratoplasty. Doctors or the eye bank take a slice from the back of a healthy donated cornea, open a small slit in the patient's eye, scrape out the diseased endothelial cells and replace them with the donor cells.
Doctors will examine patients' transplants over the next three years, to determine if the cornea has remained clear or become clouded due to poor functioning or death of the transplanted cells.
Although results of the study directly apply only to the use of donor corneas used for this specific operation and these conditions, researchers hope that results could be extended to donor corneas used for other types of transplants and other diseases.
In addition to the federal grant, the Eye Bank Association of America, individual eye banks, and the Cornea Society, which represents corneal surgeons, have contributed $315,000 to support the study.
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