OBJECTIVE: To describe the anterior segment optical coherence tomography (ASOCT) features of nodulo-ulcerative ocular surface squamous neoplasia (nuOSSN) and correlate these findings with histopathology. METHODS: Retrospective study of 16 eyes with nuOSSN with clinical images, ASOCT scans, and histopathology. RESULTS: The mean age at presentation was 55 years (median, 58 years
range, 25 to 81 years). Systemic predisposing factors included human immunodeficiency virus infection (n = 2, 13%) patients and xeroderma pigmentosum (n = 1, 6%). Bulbar conjunctiva was the most common epicenter (n = 10, 63%), with limbal and corneal extension seen in 16 (100%) and 14 (88%) eyes. In addition to epithelial thickening, typical of OSSN, scleral thinning, limbal thinning, and corneal thinning were seen in 5 (31%), 10 (63%), and 7 (44%) eyes of nuOSSN, respectively. Corneal stromal opacification with normal overlying epithelium was seen in 10 (63%) cases, corresponding to the 'wedge sign' on ASOCT in all 10 cases. This corresponded to stromal invasion of OSSN on histopathology in all eyes. The wedge sign had a sensitivity of 77%, specificity of 100%, positive predictive value of 100%, negative predictive value of 50%, and an accuracy of 81% for stromal invasion compared with the gold standard of histopathological examination. CONCLUSION: The ASOCT features of nuOSSN differ from classic OSSN. nuOSSN is associated with adjacent areas of scleral/limbal/corneal thinning. Corneal stromal opacification is seen as a wedge sign on ASOCT and corresponds to corneal stromal tumor invasion on histopathology. Areas of scleral/limbal/corneal thinning, along with the 'wedge sign' on ASOCT, confirmed nuOSSN with stromal invasion in 63% of patients in this retrospective study.