<prompt> Conjunctival mucosal overgrowth over cornea-PterygiumPingeculaVernal keratoconjunctivitisHerbes pit  <response>: Pterygium is a degenerative conjunctival fold which encroaches on the cornea in the palpebral area. It must be differentiated from pseudopterygium an inflammatory fold of conjunctiva encroaching on cornea.Pterygium L. Pterygion a wing is a wing-shaped fold of conjunctiva encroaching upon the cornea from either side within the interpalpebral fissure ref: A K KHURANA OPHTALMOLOGY,E4, Page-80 ref img 