Ocular surface squamous neoplasia (OSSN) is a term that encompasses a spectrum of epithelial squamous malignancies ranging from dysplasia to invasive carcinoma. This video evaluates the pros and cons of surgery versus interferon, 5 FU, and mitomycin as therapy. Dr. Karp shares her approach to deciding between a surgerical or a medical approach. In stubborn cases, she often uses a combination of therapies.