摘要
Introduction The word pterygium comes from two Greek words:(pteryx)meaning wing and(pterygion)fin(1-3).Pterygium,one of the most common benign tumors of the ocular surface,is a focal fibrovascular proliferation of conjunctival tissue onto the cornea(1-6).The pterygium is usually triangular in shape and localized in the nasal palpebral fissure(1-6).Histopathologically,there is usually a nonkeratinizing epithelium and loss of goblet cells(4).Some cases show also the development of a multilayered keratinizing squamous epithelium.Subepithelial features include thickened collagen fibers,numerous vascular incisions,and pathognomonic elastoid degeneration.Sometimes,chronic inflammation,such as lymphocytic infiltration,can also be seen(2-6).Furthermore,the head of the pterygium,which is firmly fused to the cornea,can also grow into the upper corneal layers and fragment Bowman’s lamella(1-4).
