To determine whether ocular cicatricial pemphigoid (OCP) may represent a distinct immunopathologic disease when it is pure ocular cicatricial pemphigoid (POCP) (e.g., only confined to the conjunctiva) or when it is associated with skin or extraocular mucous membrane lesions or both (OCP+).Prospective, immunologic, and immunopathologic study with special emphasis on direct immunoelectron microscopy.Six patients with POCP and seven patients with OCP+.After informed consent was obtained, a conjunctival biopsy was performed in all patients. Skin and extraocular mucosa biopsy specimens were harvested in selected cases only.Results of direct immunofluorescence and direct immunoelectron microscopy without freezing on conjunctival and skin biopsy specimens, indirect immunofluorescence, and Western immunoblotting analysis were analyzed.Results of direct immunoelectron microscopic examination of the conjunctiva showed the presence of immune deposits in the upper lamina lucida of the basement membrane zone in the six patients with POCP, whereas the immune reactants were located in the lower part of the lamina lucida and in the lamina densa of the basement membrane zone (conjunctiva, buccal mucosa, and skin) in the seven patients with OCP+. Direct immunofluorescence was positive in the biopsy specimens of three patients with POCP (50%) and the seven patients with OCP+ (100%). Results of indirect immunofluorescence study showed circulating autoantibody levels only in two patients with OCP+, and results of Western immunoblot analysis were negative.Results of direct immunoelectron microscopic examination of the conjunctiva support the hypothesis that POCP may be a disease entity distinct from mucocutaneous cicatricial pemphigoid.