Graft endothelial density and thickness after non-high-risk penetrating keratoplasty using short-term-preserved or organ-cultured donor corneas

The corneal endothelial cell density is essential for the pump function and the transparency of grafts after penetrating keratoplasty (PK). The purpos e of this study was to assess corneal endothelial cell density after non-hi gh-risk PK and to check for possible correlations with storage parameters o f the donor corneas using two different storage methods. Patients and Methods Endothelial cell density (specular microscope EM 1100, TOMEY, Erlangen) and central corneal thickness (ultrasonic pachymetry SP-2 000, TOMEY, Erlangen) were assessed 6 weeks, 3, 6, 9 months and one year po stoperatively in 168 non-high-risk PKs. Short-term-preserved donor corneas were used in 89 patients, whereas in 79 patients organ-cultured corneas wer e used. The donor trephination was performed from the epithelial side using an artificial anterior chamber. The postoperative treatment with topical s teroids was standardized. The mean donor post-mortem time was 9.6 +/- 8.0 h ours for short-term-preserved and 17.6 +/- 10.5 hours for organ-cultured co rneas (p < 0.0001). The storage time was 71 +/- 49 and 380 +/- 167 hours (p < 0.0001), respectively. Results Endothelial cell density did not differ significantly between the t wo storage methods (p > 0.05). At 6 weeks postoperatively, the mean endothe lial cell density was 2042 +/- 675 cells/mm(2) for short-term-preserved cor neas and 1972 +/- 522 cells/mm(2) for organ-cultured corneas (p = 0.7). End othelial cell density did not decrease significantly (p > 0.05) within the observation period of 12 months in both groups (after 12 months: 1868 +/- 9 57 cells/mm(2) and 1638 +/- 643 cells/mm(2), respectively). The mean cornea l thickness was 542 +/- 50 mu m for short-term-preserved and 541 +/- 55 mu m for organ-cultured corneas and remainded unchanged during the follow-up o f 12 months (542 +/- 42 mu m and 521 +/- 43 mu m, respectively). Neither th e group of short-term-preserved corneas nor organ-cultured corneas showed a significant correlation between endothelial cell density or central cornea thickness with post-mortem time or with storage time of the donor corneas at any postoperative stage (p > 0.1). Conclusion During the first year after PK, only a small decrease in endothe lial cell density was observed in comparison with the 6-weeks finding. The storage method does not seem to affect the short-term changes of endothelia l cell density. Further long-term studies are necessary to assess the clini cal relevance of these observations.