A hypothesis on the pathogenesis of pterygiums.

All true pterygiums are attracted to a specific site at the corneoscleral junction along the 3 to 9 o'clock meridian. The pathogenesis of a pinguecula-pterygium is postulated to be due to a noninfected inflammation at the junction of the conjunctival blood vessels and Bowman's membrane where the autolytic process of inflammation results in a protein degradation amino acid mixture which has the ability of attracting conjunctival blood vessels on the cornea. This amino acid mix is hypothesized to contain a pterygium angiogenesis factor.