Apr. 10, 2007 One donor cornea may be divided and transplanted into multiple patients with eye disease or damage, according to a report in the April issue of Archives of Ophthalmology, one of the JAMA/Archives journals.
Transplantation of the cornea, the clear membrane that covers the front of the eye, was first performed in 1905, according to background information in the article. Recent developments have allowed ophthalmologic surgeons to move from transplanting the entire cornea in every patient to more focused operations that involve removing and replacing only the diseased or damaged portion of the cornea. "Such surgical techniques provide an opportunity to make use of a single donor cornea in more than one patient," the authors write.
Rasik B. Vajpayee, M.S., F.R.C.S., F.R.A.N.Z.C.O., then of the All India Institute of Medical Sciences, New Delhi, and now of the University of Melbourne, East Melbourne, Australia, and colleagues used one cornea from a 44-year-old donor who had died of cardiac arrest to complete transplants in three patients. The corneal tissue was divided into three parts.
The first patient, a 40-year-old man, had a degenerative cornea disease that appeared only to affect the front two-thirds of his corneal tissue. He received the front portion of the donor cornea through a procedure known as automated lamellar therapeutic keratoplasty (ALTK), in which a thin slice of tissue is removed. His visual acuity before surgery was 20/200.
The second patient, a 60-year-old man, developed complications following cataract surgery and had a visual acuity of 20/400. He received the rear portion of the cornea through a technique known as Descemet stripping automated endothelial keratoplasty (DSAEK), which involves replacing damaged endothelium, or the layer of cells on the inside of the cornea.
The third patient was a 5-year-old boy who had chemical burns in his right eye. Stem cells from the donor cornea, at the junction of the cornea and conjunctiva (the membrane that covers the outer eye and inner eyelid), were transplanted to improve his vision, which was limited to counting fingers close to his face.
The procedures were all performed on the same day and were all successful. New tissue grew over the transplant in the ALTK patient after four days, and after three months the patient's visual acuity improved to 20/60. In the DSAEK patient, minor swelling in the graft cleared within two weeks, and visual acuity improved to 20/40 after three months. New tissue grew in the child after one week, and at the three-month follow-up visit, his vision had improved to 20/200.
"Our strategy of using a single donor corneal tissue for multiple patients opens up the possibility of optimal use of available donor corneal tissue and will reduce the backlog of patients with corneal blindness in countries in which there is a dearth of good-quality donor corneal tissue," the authors write. This includes India, where 300,000 donor corneas are needed each year but only 15,000 are available, with almost half of those unsuitable for transplantation. "With more corneal surgeons converting to techniques of customized component corneal transplantation in the form of anterior and posterior lamellar disc corneal transplantation, the use of a single donor cornea in more than one patient may become standard surgical practice."
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