Background and purpose: To evaluate long term results and to demonstrate safety and efficacy of non-surgical, exclusive strontium-/ yttrium-90 beta irradiation of non-operated pterygia.

Patients and methods: Between March 1977 and April 1999, 43 patients with 54 primary pterygia were treated with an exclusive strontium-/yttrium-90 beta-irradiation up to a total dose of 50 Gy divided in four fractions with one week apart. All patients were referred from the same ophthalmologist. The average follow-up were 112(G88 months (range, 12–321 months), median 96 months.

Results: The patients were referred with early symptomatic manifestations of pterygia with a mean horizontal diameter of 1.6G0.7 mm (range, 0.5–4.5 mm), which shrank to a mean diameter of 0.9G0.6 mm (range, 0–2.5 mm) after irradiation (P!0.005). There was a reduction of size in every pterygium, none of the 54 pterygia developed a recurrent growth and there were no patient with any late side effect. Following the strontium-/yttrium-90 application the process came up with an obliteration of the vessels, which resulted in a grey, thin and avascular pannus.

Conclusions: Strontium-/yttrium-90 beta-irradiation as an exclusive, non-surgical treatment for early pterygia provides a significant reduction of the size of the irradiated pterygia, is a safe and effective therapy to prevent a recurrence and can be performed without late side effects.