THE TERMS ocular pemphigus and pemphigus conjunctivae are synonymous and designate a type of pemphigus of the mucous membranes. Ocular pemphigus may be defined as a chronic, slowly progressive disease of the epithelial coat of the eye, which ultimately leads to cicatrization. It frequently is associated with vesicular lesions of the mucous membranes and sometimes with cutaneous lesions. In contrast to other forms of pemphigus, it runs a benign course as concerns the life of the patient and is usually devoid of constitutional symptoms. The etiologic agent is unknown, but the theory of a toxic origin is favored. Pemphigus is classified as acute pemphigus vulgaris, chronic pemphigus vulgaris, pemphigus vegetans, pemphigus foliaceus, pemphigus erythematosus (Senear-Usher disease) and pemphigus of the mucous membranes. Cowan and Klauder1maintained that pemphigus of the mucous membranes should be considered a distinct entity and should further be distinguished from the essential shrinkage or shriveling