There exist, in the literature, a total of 32 cases of unilateral retinitis pigmentosa.1-10 François,11 reviewing the subject, feels that in order to make this diagnosis the affected eye must show all the classical symptoms and signs of the disease and the healthy eye have no trace of the lesion; that the patient be observed over a sufficiently long period of time to preclude the later development of the disease in the fellow eye; and that systemic causes of a secondary retinitis pigmentosa be ruled out. In addition to the usual clinical findings, we believe that a unilateral case should have a nonrecordable or greatly diminished electroretinogram and adaptometric findings indicative of loss of rod function in the affected eye only. Less rare than unilateral cases are patients in whom all the findings usually associated with retinitis pigmentosa are present but whose fundi are lacking the usual