A material of Open Angle Glaucoma (G) collected by an eye practitioner (B S) from 1980 to 1991 is analysed with special respect to the occurrence of disc haemorrhages (Hs) and retinal vein occlusions (VOs). There is a close association between Hs and VOs and G, which in all categories increases with increasing follow-up time. Furthermore, the occurrence of mixed cases--H in one eye and VO in the same or the other--support the opinion that Hs, branch vein occlusions and central vein occlusions are manifestations of the same vascular disease, the difference between them being the size of the vessel affected. The well known morphological changes in the retinal veins of glaucomas and in central vein occlusions are endothelial proliferations causing progressive increase of flow resistance. Similar changes most probably also cause branch occlusions and disc haemorrhages. The vascular affection which obstructs the vessels with hindrance of the blood flow and impaired nutrition of neuronal tissue, might be the primary cause of glaucoma.