Pigmentary degeneration of retina which is hereditary is a kind of chronic progressive disease of fundus. In clinic, it mainly manifests the symptoms of night blindness and gradual contraction of visual field. Monocular attacking occasionally, it is often characterized by the binocular onset, obviously familial heredity, consanguineous marriage of parents and more male patients than the female (a pro-
portion of three to two). The morbidity of the disease, according the survey in some parts of China, is about1/3 500.