Corneal Transplants Can Carry Infection Risk
TUESDAY Feb. 12, 2008 -- People who donate corneas are giving the gift of sight, but they may also be passing along a serious infection to the recipients, a new study finds.
This infection, called endophthalmitis, most commonly comes from donors who die in a hospital or had cancer, according to the report in the February issue of the Archives of Ophthalmology. Endophthalmitis is a rare but serious complication of corneal transplant surgery and can result in loss of vision or blindness in the affected eye.
"A national study over a decade showed that serious infection with endophthalmitis, after corneal transplant surgery, is uncommonly reported, but can be caused by a range of microbes, including bacteria and fungi," said study co-author Dr. Kirk R. Wilhelmus, a professor of ophthalmology at Baylor University College of Medicine in Houston. "The chance for infection is higher if eye tissue donations came from decedent donors who died in the hospital or with advanced cancer," he added.
For the study, the researchers used data from a registry that collected information on cases of eye infection after transplants done between 1994 and 2003. Over the 10 years, eye banks distributed 340,174 corneas in the United States and 109,009 in other countries. There were a total of 162 cases of endophthalmitis reported during that time.
The odds that someone was infected by a donor who had been hospitalized were three times greater when compared with a recipient who was not infected. Moreover, getting an infection was substantially more likely if the donor had died from cancer, the researchers found.
Although infections are rare, they do occur, and may be due to infections picked up in the hospital. "Donor tissue can harbor microorganisms that can persist despite antiseptics, sterile procedures, and antibiotics," Wilhelmus said.
Still, corneal transplant surgery is largely a safe and effective procedure, but infection is possible Wilhelmus said. "Eye banking procedures appropriately include quality control procedures for screening potential donors," he said.
To reduce the risk of infection, donors who had blood or other infections are often not allowed to donate corneas. Also, antiseptic tools are used when removing the cornea from the donor and preserving it before transplant.
One expert thinks that because the risk of infection is so small, patients should not fear having corneal transplant surgery.
"The number of infections is very small," said Dr. Joel Sugar, a professor of ophthalmology and visual science at the University of Illinois at Chicago Eye Center and author of an accompanying editorial in the journal. "The Eye Bank Association of America has a very stringent and effective system for reporting such cases."
People who die in hospitals or from cancer make up the largest number of cornea donors, Sugar noted.
"To eliminate those categories for this low-risk event does not make sense. It does highlight, however, the ongoing need to be vigilant in looking for risk factors for infections and doing everything we can to reduce the frequency of infections, even though they are exceedingly small," he said.
Another report in the same issue of the journal concludes that older white people are more likely to develop advanced forms of age-related macular degeneration than black people.
In the study, Dr. Susan B. Bressler, of Johns Hopkins University School of Medicine, and colleagues found that whites 65 and older were more likely to have advanced macular degeneration than blacks -- 1.7 percent versus 1.1 percent, respectively.
What's more, a form of macular degeneration called geographic atrophy was more common among whites than blacks -- 1.8 percent compared to 0.3 percent, the researchers found.
"Such data strongly suggest that white individuals are more likely to progress to advanced vision-disabling age-related macular degeneration (certainly to geographic atrophy) than black individuals," Bressler's team concluded. The researchers also suggested that blacks may have a mechanism that protects them from age-related macular degeneration and other eye problems.
For more on corneal transplants, visit the U.S. National Eye Institute.
Posted: February 2008