Evaluation of penetrating keratoplasties with long-term cryopreserved corneas using simplified method

Since March 1986, the authors have studied and simplified the corneal cryopreservation technique using a self-made QL Bio-freezer. On the basis of successful animal experiments, penetrating keratoplasties with human cadaver corneas cryopreserved 9 to 571 days (averaging 131 days) were performed in 60 patients (61 eyes). The patients were followed up for 1.5 to 50 months. 41 of the corneal grafts remained clear, 9 became translucent and 11 cloudy. A total of 46 eyes had their visual acuity improved significantly. The results show that clinical use of corneal cryopreservation by the simplified two-step method is noteworthy.