Current and emerging strategies for the manufacture, implantation, and clinical management of corneal tissue allografts.

Approximately 40,000 Australians have received a donor corneal tissue transplant over the last 40 years, with the primary indications being keratoconus, Fuchs' endothelial dystrophy, bullous keratopathy, and failure of a prior corneal transplant. Although corneal cross-linking and rigid contact lenses have emerged as alternative strategies for the management of keratoconus, the demand for donor corneas is increasing in-line with the ageing population in Australia. Moreover, owing to the lack of tissue banking resources in less-developed countries, the global demand for donor corneas exceeds supply by 70-fold. These supply issues, combined with evolving tissue banking and surgical techniques, have led to the emergence of new strategies for the storage, processing and implantation of corneal cells and tissues. Organ culture techniques have been developed that support the storage of donor corneas for up to 30 days, facilitating improvements in tissue supply and surgery scheduling. Bespoke surgical methods have been developed that are tailored to the requirements of specific conditions, allowing reductions in both the volume of tissue required to be transplanted and the size of the necessary surgical incision. Further efficiencies and improvements in patient care may be achieved via exploitation of cell culture technologies as exemplified through use of cultured corneal epithelial cells for the treatment of limbal stem cell deficiency. Promising progress has also been made in developing a cultured corneal endothelial cell therapy for patients with corneal endothelial dysfunction. These evolving strategies are discussed with respect to their potential impact on the clinical presentation and management of patients who have received an implant of donor corneal tissue or cells.