Sections from the anterior segment of the fetal and adult human eye and from limbal tissue excised during standard trabeculectomies were studied immunohistochemically with monoclonal antibodies against human tenascin or monoclonal antibodies against cellular fibronectin (cFN). In the fetal eye, tenascin-like immunoreactivity (TEN-LI) was observed in the area of the developing limbus. In the adult eye TEN-LI was most intense at the corneoscleral margin in the stromal tissue and decreased towards the posterior sclera. No reaction was observed in the corneal stroma, but the epithelium showed moderate immunofluorescence. All tissues obtained during trabeculectomy showed similarly strong TEN-LI. The sections from trabecular specimens incubated with antibodies against cFN were negative.