Histology of pterygium: an electron microscopic study.

An electron microscopic study of the cap areas of several pterygia shows the presence of active fibroblasts in the natural tissue planes surrounding Bowman's layer. The hypothesis is advanced that the fibroblasts originate in the limbal connective tissue. They advance in the cornea above and below Bowman's membrane, destroying the latter and a variable amount of superficial corneal stroma.