Background/aims: To compare the effectiveness and side effect profile of two doses of interferon alpha2b (IFNα2b) eye drops (1 million international units (IU)/ml versus 3 million IU/ml) in the treatment of ocular surface squamous neoplasia (OSSN).
Methods: Retrospective case series.
Results: Thirty-five eyes were identified over an 11 year period (1996-2007). Twenty-one eyes (19 patients) with conjunctival intraepithelial neoplasia (CIN) were treated with 1 million IU/ml of topical IFN-α2b; 12 eyes (9 patients) with CIN were treated with 3 million IU/ml. Two patients with squamous cell carcinoma (SCC) were treated with topical interferon, one with 1 million IU/ml and one with 3 million IU/ml. Baseline demographic information was not statistically different between the two groups. In patients with CIN, topical therapy eliminated disease in 81% of eyes in the 1 million IU/ml group versus 92%, in the 3 million IU/ml group, p=0.41. The median time to OSSN resolution was 2.8 months in the 1 million IU/ml group and 1.9 months in the 3 million IU/ml group, p=0.55. Neither eye with SCC responded to interferon therapy. Topical therapy was well tolerated. After median follow up of 24 months, three recurrences were seen in eyes successfully treated with topical therapy.
Conclusion: In our study, there were no significant differences between the 1 million IU/ml group and the 3 million IU/ml group for the treatment of CIN.