PRE-OPERATIVE DETECTION OF OCULAR SURFACE SQUAMOUS NEOPLASIA IN PATIENTS WITH PTERYGIUM USING ANTERIOR SEGMENT OPTICAL COHERENCE TOMOGRAPHY

Abstract

Pterygium is one of the most common ocular surface disorders. It is considered a fibrovascular overgrowth arising from subconjunctival tissue, triangular in shape, and encroaching on the cornea located in the medial and lateral palpebral fissure. Squamous metaplasia may be present in pterygia specimens.OSSN is the term including the pre-malignant and malignant epithelial lesions of the conjunctiva and cornea. This spectrum includes Dysplasia, Carcinoma in situ (CIS) and Invasive SCC.Risk factors for both pterygium and OSSN are closely the same, UV ray exposure being the most important of them. However, Management plans differ significantly for both pterygium and OSSN. This highlights the importance of preoperative detection and therefore the prognosis.AS-OCT is a safe non-invasive imaging modality. It has an important role in evaluating anterior segment structures including the cornea, anterior chamber, and iris. On AS-OCT, pterygium is a subepithelial hyper-reflective lesion extending from the conjunctiva into the cornea, causing separation of the corneal epithelium from basement membrane (BM). However, OSSN presents as a thickened hyper-reflective epithelial lesion with an abrupt transition between normal and abnormal epithelium.