Experimental and pathologic studies implicated the role of the epithelial basement membrane and its associated hemidesmosomes and anchoring fibrils in mediating tight adhesion between corneal epithelium and stroma. We evaluated the ultrastructural quality of basement membrane complexes in patients with Reis-Bücklers dystrophy, Cogan's microcystic dystrophy, and nontraumatic recurrent erosion who presented with clinically significant erosive symptoms. Despite the variable clinical and histopathologic appearances among these dystrophies, incompleteness of basement membrane complexes apparently was a common fault shared by these erosive disorders. Such basic incompetence at the basement membrane level can both provoke and sustain erosions, while the more individual pathologic manifestations of a given anterior dystrophy may be of less primary significance.