OR WAIT null SECS
The development of customized component corneal transplantation techniques could enable a single donor cornea to be used to treat multiple patients. The practice could help address tissue shortages and reduce the wait time for surgery in developing countries. A researcher formerly practicing in India talks about the first published report of this strategy.
East Melbourne, Australia-Customized component corneal transplant techniques may help relieve shortages of donor corneas by allowing the use of one cornea in multiple patients. In the first published report of this strategy, Rasik B. Vajpayee, MS, FRCS, FRANZCO, described three successful procedures using one cornea from a 44-year-old donor who died of cardiac arrest.
All of the procedures were performed in the same day at the Dr. Rajendra Prasad Center for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, where Dr. Vajpayee was employed at the time. He now is a professor of ophthalmology and head of corneal and cataract surgery at the Centre for Eye Research Australia, Department of Ophthalmology, University of Melbourne, East Melbourne, Australia.
In the first case, the anterior lamellar disc of the donor cornea was transplanted into a man, aged 40 years, with macular corneal dystrophy involving only the anterior two-thirds of corneal stroma. He received the front portion of the cornea during an automated lamellar therapeutic keratoplasty (ALTK) procedure. New tissue grew over the transplant within a few days, and his best-corrected visual acuity (BCVA) improved from 20/200 preoperatively to 20/60 3 months postoperatively.
In the third case, a boy, aged 5 years, with total limbal stem cell deficiency in one eye due to chemical burns received two partial-thickness corneal limbal stem cell lenticles harvested from the peripheral corneoscleral rim of the donor cornea. Before surgery, his vision was limited to counting fingers close to his face. The corneal epithelium regenerated in the first week postoperatively; the operated eye developed mild inflammation, but the ocular surface was stable at 3 months, and BCVA was 20/200. The child was scheduled to undergo optical penetrating keratoplasty.
First to publish
Dr. Vajpayee said he was uncertain whether other corneal surgeons had divided donor corneas for use in more than one patient but believes that he and his colleagues were the first to publish their experiences. Their report on this new concept for corneal transplantation surgery appeared in the April 2007 issue of Archives of Ophthalmology (125:552–554).
The first corneal graft was performed in 1905. Until recently, the two main techniques for corneal transplant were full-thickness and partial-thickness procedures. These procedures, however, required using all of the donor corneal tissue even in cases where only a small portion was needed for a successful transplant, Dr. Vajpayee said.
Lately, customized component corneal transplantation techniques such as DSAEK and ALTK have come into vogue. These approaches are designed to replace only the diseased portion of the cornea with healthy donor tissue. These techniques not only have resulted in fewer postoperative complications but also have opened the door for using one cornea in many patients, he continued.
"In a country like India, where I was working previously, there is a shortage of corneal tissue. If one patient had disease only in the anterior cornea and one patient had disease only in the posterior cornea, we would split the tissue in two parts and use it for those two patients," Dr. Vajpayee said. "That way, the tissue does not go to waste, and it also decreases the waiting time for surgery."
Dr. Vajpayee said that in India, about 300,000 donor corneas are needed each year, but only 15,000 are available, and almost half of those corneas are unsuitable for transplantation. Using a single cornea for more than one patient could help address the shortage in India and other developing countries that have a scarcity of donor tissue. Not all patients could be treated with selective replacement of diseased corneal tissue, but multiple use of donor tissue could become a standard surgical procedure in appropriate cases, he added.
"It is not a panacea, but it is a new concept, and it can be useful for the optimal use of donor corneal tissue," Dr. Vajpayee concluded.