[Etiopathogenic aspects in development and evolution of pterigyum].

Pterygium is an epithelial hyperplasia accompanied by a fibrovascular growth originating at the corneo-conjunctival junction, from where the modified limbic cells migrate and surpass the cornea. The studies reviewed show that it is an active process associated with cell growth, remodelling of the connective tissue, angiogenesis and inflammation. Despite the lack of knowledge regarding the pathogenesis of pterygia, epidemiologic evidence suggests that exposure to UV-irradiation may be an initial trigger in the development of this lesion.