<prompt> Pterygium is-A vascular anomalyA connective tissue degenerationAn inflammatory conditionAssociated with Vit. A deficiency  <response>: Pathologically pterygium is a degenerative and hyperplastic condition of conjunctiva. The subconjunctival tissue undergoes elastotic degeneration and proliferates as vascularised granulation tissue under the epithelium, which ultimately encroaches the cornea. The corneal epithelium, Bowmans layer and superficial stroma are destroyed. ref: A K KHURANA OPHTALMOLOGY,E4, Page-80 