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 lo st. In our retrospective study two questions were investigated: 1) is it po ssible to restore the limbal region by transplantation of large diameter ke ratoplasties 2) has the time of transplantation an influence on the clinica l outcome. Patients and method: In a retrospective study the outcome of 48 eyes (43 pa tients) with severe chemical and thermal burns were analysed. Large diamete r (11-12 mm) penetrating keratoplasties were performed between 1987 and 199 6. Complete limbal deficiency was present in 17 eyes, while 31 eyes had dev eloped 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 = 1 1): 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 fai led due to surface problems, 18.8% due to endothelial rejection episodes. L ate keratoplasties were significantly more successfull than intermediate ke ratoplasties. 25% of the early keratoplasties and 36.4% of the late keratop lasties showed an intact limbal region at the end of the follow-up time, bu t 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.