Frequency and Risk Factors for Pterygium in the Barbados Eye Study

Abstract

DURING THE last several decades, numerous theories have been suggested for the pathogenesis and formation of pterygia. These include excessive exposure to ultraviolet light,¹ chronic infection and thrombosis of conjunctival veins,^2,3 invasion of the cornea by subconjunctival fibroblasts,⁴ and the presence of a pterygium angiogenesis factor that causes new vessels to proliferate on the cornea.⁵ Pinkerton et al⁶ proposed an immunologic mechanism, based on the finding of infiltration of small lymphocytes and plasma cells in the pterygium. More recently, the focus on the pathogenesis of pterygium has changed from a degenerative process to a proliferative condition. This theory is supported by a report on the abnormal expression of the p53 tumor suppressor gene in the conjunctiva of patients with pterygia.⁷