[Methods of preserving donor corneas]

Corneal transplantation is the most successful and frequently performed allotransplantation procedure. Benign outcome of penetrating and posterior keratoplasty depends on viability of the corneal tissue and presence of the proper endothelial layer, which retaining is one of the main objectives of preservation of donor material. Methods designed to reach this goal may be classified according to storage duration as short-term (storage in a moist chamber), medium-term (hypothermia), long-term (organ cultivation) and unlimited (cryopreservation). While there are reports of successful application of cryo-conserved corneas for penetrating keratoplasty, its use for this type of transplantation is limited due to complexity of the method and very high requirements for the quality of donor material. However, being a method of unlimited storage, it still attracts the attention of researchers. Taking into account the ongoing development of innovative keratoplasty technologies and the tendency for predominant use of layered grafts that in some cases do not need viable endothelium, methods of preservation of such material for anterior lamellar and intralamellar keratoplasties become relevant. In this context, cryopreservation without the use of cryoprotective agents is promising because it allows simple and fast accumulation of large amount of material with long storage time. Further research on the development of preservation methods of the corneal endothelial layer at sub-zero temperatures may allow storing the material by cryopreservation that will be suitable for penetrating and posterior keratoplasty.