Purpose: To evaluate the imaging characteristics of intraepithelial and invasive ocular surface squamous neoplasia (OSSN) on high-resolution anterior segment optical coherence tomography (ASOCT).
Methods: In this prospective cross-sectional study, 17 consecutive patients (10 intraepithelial and 7 invasive) with histopathologically proven OSSN were included. All patients underwent slit-lamp imaging and time-domain ASOCT at premarked sites. Management included standard complete surgical excision with margin clearance and cryotherapy for all cases. The correlation between imaging characteristics and histopathology sections at the premarked sites was analyzed to determine surrogate markers that may help differentiate intraepithelial from invasive OSSN. In addition, 3 patients with presumed OSSN underwent serial ASOCT for surveillance.
Results: All tumors were staged as T3N0M0 except 2 that were staged as T1N0M0 by the eighth edition of the American Joint Committee on Cancer (AJCC). Mean age was comparable between the 2 groups (56 years vs. 54 years for intraepithelial and invasive groups, respectively, P = 0.79). ASOCT characteristics included all cases (100%) showing a hyperreflective thickened epithelium and abrupt transition between normal and abnormal epithelium. Nine of 10 (90%) intraepithelial OSSN showed a clear plane of separation. A hyperreflective basal membrane was seen in 60% of intraepithelial OSSN, and hyporeflective zones were seen in 57% of invasive OSSN. Mean thickness was 924 and 1662 µm in intraepithelial and invasive OSSN, respectively (P = 0.02, Mann-Whitney test).
Conclusions: A visible clear plane of separation and increased thickness on ASOCT may serve as surrogate markers of intraepithelial OSSN and help differentiate it from invasive OSSN.