Material and methods: [corrected] In the Institute of Radio-Oncology in Lucerne we reviewed the records of 75 patients with 97 pterygia in a retrospective study. All patients had the same number of fractions (4), the same single fraction dose (1250cGy) and the same total dose (5000cGy). The operation technique used was the bare sclera technique. Patients were treated following three different concepts. The first group was treated prior to the operation, 1 fraction weekly, at least 2 months before operation. The second group was treated postoperatively, also one fraction weekly, immediately after operation. The third group received 2 fractions prior to and 2 fractions following operation.

Results: We observed only 2 out of 97 (2%) recurrences in the second group. Because of their clinically inactive behavior these two cases required no further treatment. Three patients showed teleangiectasia as a moderate reaction. As a severe complication we observed one ulcus corneae, which was successfully treated with a lamellar keratoplasty, for a complication rate of 1%.

Conclusion: Beta irradiation has proved to prevent pterygium recurrence. Severe late complications after excision and B-irradiation may partly be caused by other factors than irradiation alone. But it seems unequivocal that there is a relation with the high single-dose procedure of more than 2200cGy or re-irradiation. Fractionation must therefore be used.