Immunohistochemical localization of collagen types I, II, III, and IV in pterygium tissues

Distribution of extracellular matrix proteins in pterygia: an immunohistochemical study

“…Against this background the present investigation proved the expression of various ECMs and epithelial cell proteins in pterygial tissues in a hitherto unknown specification. The stroma of normal conjunctiva contains collagen types I, II, and III, while the normal corneal stroma contains collagen I and III but not II [5]. In contrast, collagens I, II, and III were found in pterygial stroma [5].…”

Pathogenetic mechanisms and treatment options for ophthalmic pterygium: Trends and perspectives (Review)

“…Epithelial changes are variable and include hyperkeratosis, parakeratosis or akanthosis (21). Fibroblasts lying at the anterior corneal stroma (underneath Bowman's membrane) may become activated by ultraviolet radiation and may cause Bowman's membrane rupture resulting in the firm adherence of pterygium on underlying corneal stroma (22). On the contrary, the presence of Tenon's capsule prevents the adherence of the episcleral portion of pterygium on the underlying sclera (21,22).…”

“…Fibroblasts lying at the anterior corneal stroma (underneath Bowman's membrane) may become activated by ultraviolet radiation and may cause Bowman's membrane rupture resulting in the firm adherence of pterygium on underlying corneal stroma (22). On the contrary, the presence of Tenon's capsule prevents the adherence of the episcleral portion of pterygium on the underlying sclera (21,22). From a histochemical standpoint, abnormal forms of mucopolysaccharides, often with increased amounts of neutral sugars and sialic acid, are reported in pterygia, together with higher levels of specific amino acids, such as praline, compared with normal conjuctiva (23)(24)(25).…”

Prevalence and severity of pterygium among commercial motorcycle riders in south eastern Nigeria

“…2 It is speculated to be associated with corneal and conjunctival microtrauma from exposure to sunlight and/or dust 3 . The exposure to UV light is thought to cause repeated rapid evaporation and destruction of the tear film with subsequent elastoid degeneration of the sub epithelial connective tissue.…”