Corneal preservation: recent advances.

New methods of corneal preservation for penetrating keratoplasty have recently been developed to meet the increasing demand for donor corneal tissue. Techniques utilized in the laboratory to evaluate the viability of the corneal endothelium and the clinical results obtained with each method are discussed. All of the new methods (storage in serum or McCarey-Kaufman medium, cryopreservation and organ culture) required excision of the cornea from the donor eye. Good clinical results have been obtained in several ophthalmology centers with cryopreservation and storage in McCarey-Kaufman (M-K) medium. Storage in M-K medium has rapidly become popular because it is a simple and inexpensive method and appears to maintain endothelial viability for about 4 days. Cryopreservation is a more complicated procedure, but it enables longterm storage of donor tissue. Organ culture is still experimental and requires careful technique, but offers promise of maintaining endothelial viability for 3 to 4 weeks.