Ultrasound biomicroscopy and anterior segment OCT in ocular surface squamous neoplasia: complementary roles, case series, and targeted literature review.

Introduction: Ocular surface squamous neoplasia (OSSN) encompasses a spectrum of epithelial malignancies of the conjunctiva and cornea that, untreated, may invade intraocularly or into the orbit. Clinical examination alone may fail to define true depth of invasion, risking under- or overtreatment. Advanced anterior segment imaging provides objective structural information that complements slit-lamp assessment. Methods: This review summarizes the complementary roles of anterior segment optical coherence tomography (AS-OCT) and ultrasound biomicroscopy (UBM) in assessing OSSN depth through a targeted literature review and illustrates their practical applications through representative cases from a single tertiary center. Results: AS-OCT offers non-contact, high-resolution imaging of the epithelium and stromal interface, facilitating detection of invasive change. UBM, with deeper penetration, visualizes the sclera, ciliary body, angle, and iris, detecting deep or clinically occult extension. The cases demonstrate how each imaging modality contributes to refining diagnosis, guiding treatment selection, and supporting long-term surveillance. Discussion: Applying AS-OCT for superficial disease and UBM for suspected deep extension enhances diagnostic confidence and supports personalized, globe-preserving management. Integrating both modalities into a stepwise imaging workflow can improve staging accuracy and align treatment intensity with true disease extent.