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a uniocular retinopathy associated with occlusion of the central retinal vein; a nonischemic central retinal vein occlusion.
retinal vein occlusion
Occlusion of the central retinal vein (CRVO) can be either non-ischaemic CRVO (venous-stasis retinopathy) which is the most common type, or ischaemic CRVO (haemorrhagic retinopathy). Predisposing causes are cardiovascular disease, systemic hypertension, diabetes or raised intraocular pressure. Non-ischaemic CRVO is characterized by some loss of vision, metamorphopsia, slight impairment of the pupil responses to light and partial or complete central scotoma due to macular oedema. The ophthalmoscopic picture shows retinal haemorrhages, flame-shaped in appearance and distributed throughout the whole fundus, dilated and tortuous veins and a swollen optic disc. In some cases cotton-wool exudates are also noted. When the condition affects young adults it is commonly referred to as papillophlebitis (optic disc vasculitis) in which the clinical picture is similar except that the pupillary responses to light are normal and the patient is often asymptomatic. Ischaemic CRVO, which usually affects older people, is a more severe type and the signs and symptoms are much more marked than in the non-ischaemic type.Occlusion is more frequently limited to one branch of the central retinal vein (BRVO). In this case the clinical picture is limited to the etinal area drained by the occluded branch, but most patients will have some loss of vision depending on the extent of the macular oedema. Many eyes with BVRO have been found to be hyperopic. Treatment depends on the primary cause. Photocoagulation is used in some cases (Fig. R12). See fluorescein angiography; rubeosis iridis; central retinal vein.