The contributions Donald Doughman, M.D., made to corneal tissue preservation more than 30 years ago have had a long-lasting impact on corneal transplant surgery.
When he arrived at the University in 1972, tissue from donated corneas were transplanted within 24 hours, which meant that patients had to be near a phone at all times with their bags packed, and surgeons often had to get up in the middle of the night to perform transplant operations, says Doughman, professor of ophthalmology and medical director of the Minnesota Lions Eye Bank. “Corneal transplants were done on an emergency—not an elective—basis,” he says.
Physicians followed the 24-hour rule because there was no evidence showing how long it was safe to use unpreserved corneal tissue. Because they were concerned about the risk of infection, surgeons exercised caution.
While working with researchers who studied methods for skin preservation, Doughman noticed some significant anatomical similarities between skin tissue and corneal tissue. In 1974 he began transplanting corneas that had been preserved in culture media similar to the media used to preserve skin tissue. This preservation technique made it possible to safely transplant corneal tissue that wasn’t used within 24 hours of being harvested. In fact, Doughman’s study showed that corneal tissue could be stored safely for up to a month using this method.
One limitation to this technique was that preserving corneal tissue in culture media at body temperature altered the characteristics of the tissue, making it difficult to handle.
In a follow-up study, Doughman examined preservation at refrigeration temperatures and showed that corneal tissue preserved in culture media could be kept safely at refrigeration temperatures for four to five days. This method did not alter the tissue, making it easier to handle. And considering that refrigeration dramatically reduced the risk of infection, this method of preservation became widely accepted in the field.
“Over time, with surgical advances made in ophthalmology, there has been an increased need for corneal tissue for transplants,” says Doughman, “and with these preservation techniques, it is possible to store corneas like we store money in a bank. This has given us the luxury of scheduling a patient’s corneal transplant surgery a month in advance, knowing that we will have tissue available at that time.”
Robert Letson, M.D., a retired associate professor in the Department of Ophthalmology, says Doughman has made many important contributions to the department and to the field in general during his time at the University. During Doughman’s tenure as department chair, he helped develop additional clinical specialties besides pediatric ophthalmology and retinal and anterior segment diseases, the two that previously existed in the department, Letson says. Doughman also pioneered this corneal preservation method in cooperation with the Minnesota Lions Eye Bank and has been a successful director of the Eye Bank for many years.
“Dr. Doughman worked very diligently to develop a method for corneal preservation,” Letson says. “His research has made a positive difference to countless patients.”