1. It was confirmed by Y. Hashimoto et al. that muscle dystrophy of the carp was caused by oxidized oil in the diet.
2. In the present research, ophthalmoscopic and histopathologic inspections were made of the eye fundus of the carp fed on the diet containing the oxidized oil.
3. Such symptoms of arteriosclerosis as hyaline degeneration, hypertrophy or necrose of the wall of vitreal vessels were observed.
4. Other symptoms observed were local or diffused decolourization and partial projection of retina. It was confirmed by histological examinations that the decolourizations of retina were caused by the disintegration of the pigment, distributed outer surface of the pigment epithelium, and that the projections of retina caused by the hypertrophy of the pigment epithelium.