Occlusion of the central retinal vessels.

A CONSIDERATON of the occlusion of the central retinal vein cannot be regarded as a new thing because a tremendous amount of literature exists on the subject. In spite ofthis, there are many lacunae in our knowledge, so that the existing information cannot explain all the various aspects of the clinico-pathological picture of central retinal vein occlusion. Any additional data based on experimental observations may help to resolve the numerous speculations and discussions that have continued until now. The clinical findings in cases of so-called central retinal venous occlusion have suggested from time to time the possible involvement of the retinal arteries as well as the veins, and a close association between the two. This has been particularly so because of the following observations: (1) Frequent association of central retinal vein occlusion with old age, arteriosclerotic changes, and arterial hypertension. (2) The occurrence of a sector defect in the field of vision in cases of branch occlusion similar to that of an arterial branch occlusion. (3) A very high incidence of permanent blindness in cases of clinical retinal venous occlusion (Cassady (1953) saw it in 80 per cent.). (4) The histopathological examination in cases of obstruction of the central retinal vein shows atrophy of the inner layers of the retina up to the inner nuclear layer, though the visual cells are not affected (Elwyn, 1946), a picture similar to that of arterial occlusion. Recently, while investigating the pathogenesis of oedema of the optic disc (papilloedema) (Hayreh, 1964), some interesting observations on this aspect of central retinal venous occlusion were recorded on direct blockage of the central retinal vessels in Rhesus monkeys. These have been considered worth reporting in detail.