Purpose: Prospective study to evaluate consecutive treatment results and to demonstrate safety and efficacy of nonsurgical, exclusive strontium-/yttrium-90 β-irradiation of nonoperated pterygia.

Patients and Methods: Between November 1999 and March 2002, 20 patients with 21 primary pterygia and six patients with recurrent pterygia after former surgery were treated with exclusive strontium-/yttrium-90 irradiation up to a total dose of 3,600 cGy (six fractions) and 4,800 cGy (eight fractions), respectively. All patients were referred from a single institution. The mean followup is 35.6 ± 7.3 months (range 24–48 months).

Results: Prior to irradiation the mean horizontal diameter of all pterygia was 2.6 mm and shrank to a mean diameter of 1.6 mm

after treatment (p = 0.0011, Student’s t-test). The treatment led to a reduction in size of all 21 primary and all six recurrent

pterygia.

Visual acuity reached a value of 0.73 before and 0.82 after treatment. This improvement was not significant in Student’s t-test (p = 0.12). The visual acuity did not decrease in any patient, complications were not observed, and in none of the 27 pterygia a recurrence developed.

Conclusion: Exclusive strontium-/yttrium-90 irradiation of the early and moderately advanced pterygium is a very efficient and very well-tolerated method of treatment. As to the therapeutic management, it is suggested to apply β-irradiation prior to the development of an astigmatism-relevant pterygium, which requires excision.