[Long-term results of large diameter keratoplasties in the treatment of severe chemical and thermal eye burns].

BACKGROUND

In severe chemical and thermal eye burns the limbal stem cells, which are important for the regeneration of the corneal epithelium, are lost. In our retrospective study two questions were investigated: 1) is it possible to restore the limbal region by transplantation of large diameter keratoplasties 2) has the time of transplantation an influence on the clinical outcome.

PATIENTS AND METHOD

In a retrospective study the outcome of 48 eyes (43 patients) with severe chemical and thermal burns were analysed. Large diameter (11 - 12 mm) penetrating keratoplasties were performed between 1987 and 1996. Complete limbal deficiency was present in 17 eyes, while 31 eyes had developed sterile corneal ulceration. According to the time of transplantation three different groups were distinguished. Group I (early keratoplasty, n=24): transplantation within 3 months after the accident (mean: 26 days). Group II (intermediate keratoplasty, n=13): transplantation between 4 - 18 months after the burn (mean: 190 days). Group III (late keratoplasty, n=11): surgery more than 18 months after the injury (mean: 36.6 months).

RESULTS

Follow-up time was 28.4 months in early keratoplasty, 26.4 months after intermediate keratoplasty, and 34.3 months in late keratoplasty. Long-term results of the keratoplasties were poor. 60.4 % of the transplants failed due to surface problems, 18.8 % due to endothelial rejection episodes. Late keratoplasties were significantly more successful than intermediate keratoplasties. 25 % of the early keratoplasties and 36.4 % of the late keratoplasties showed an intact limbal region at the end of the follow-up time, but none of intermediate keratoplasties.

CONCLUSION

The prognosis for large diameter keratoplasties depends on the time of transplantation. Late and early keratoplasties had the best results. However, survival of heterologous stem cells is limited.