Among various diseases of the retina, pigmentary degeneration was always considered one of the best outlined clinical entities. The ophthalmoscopic appearance of this disease, the changes in the visual fields, the state of adaptation and even the histopathologic observations, whenever they were available, presented little difficulty in diagnostic interpretation. However, with the introduction of finer methods of clinical investigation and with the accumulation of larger clinical experience, some atypical and rudimentary forms of pigmentary retinitis became known. Then new problems requiring further investigation came into existence. An unusual variation of pigmentary retinitis, its unilateral form, was first reported as early as 1865 (Pedraglia1 ). So rare, however, was the unilateral occurrence of this disease that fifty years after the first report Leber2 could find only fourteen similar cases in the literature. Of these, several were excluded because they seemed unreliable. It is not surprising under these circumstances