JUL 16, 2008
Comprehensive Ophthalmology, Cornea/External Disease
The primary purpose of the Cornea Donor Study was to determine if the five-year survival rate of corneal tissue grafts taken from donors older than 65 years was similar to grafts from younger donors. The study's researchers found that the five-year graft survival rate was the same for patients who received corneas from either older or younger donors. The results of this research demonstrate that the cornea donor pool should be expanded to age 75.
The double-masked controlled clinical trial involved 105 surgeons at 80 sites, 43 eye banks, and 1090 patients aged 40 to 80 years with corneal disease that placed them at moderate risk of graft failure. Most had been diagnosed with Fuchs' dystrophy or pseudophakic corneal edema. Corneas were required to come from donors aged 10 to 75 years and have baseline endothelial cell densities (ECD) between 2300 and 3300 cell/mm2.
Baseline ECD was slightly higher among the 707 younger donors, who ranged in age from 12 to 65 years, compared with the 383 older donors (2680 versus 2624 cells/mm2). Interestingly, the five-year graft survival rate was 86 percent for the corneas from each of the donor groups. The rates of graft failure due to specific causes were also similar.
A second paper from the same research group sought to determine if endothelial cell loss after five years in successful transplantation cases varied with donor age. The subjects in this study were 347 participants in the initial study who had not experienced graft failure after five years. Among this group, baseline ECD was significantly higher among the 239 subjects who had received corneas from younger donors than among those with corneas from older donors (2731 versus 2585 cells/mm2), as was ECD after five years (824 versus 654 cells/mm2). The percentage ECD decrease was significantly lower among the corneas from younger donors than from older ones (69 percent versus 75 percent), and there was a weak negative association between ECD and donor age. This relationship may affect graft survival over longer periods.
Many eye banks have an upper age limit of 65 for donors. With the bulge in the U.S. population from baby boomers, the demand for cornea transplants will increase. There will also be a relative decrease in suitable younger donors. Together with stringent FDA corneal transplantation regulations, this may stretch the ability to meet the demand for transplantable corneas in the United States.
Eye banks should expand their eligibility criteria to include donors up to age 75, and surgeons and patients should be able to feel comfortable with older donor tissue since it has been found to have the same five-year graft survival rate as younger donor tissue. If eye banks adopt this change, we can improve the worldwide supply of cornea donor tissue.
Dr. Banitt has no financial interests to disclose.