LATE COMPLICATIONS IN BRANCH RETINAL VEIN OCCLUSION

Neovascularization in branch retinal vein occlusion usually develops 6 -12 months after the onset of the disease, although some cases have be en reported in which neovascularization and subsequent vitreous haemor rhage developed 2-3 years later. This is a report of nine cases of lat e appearance of vitreous haemorrhage due to branch retinal vein occlus ion, which occurred 3-6 years after the initial onset of the disease. In two of these nine cases the vitreous haemorrhage was very profound and had to be managed by vitrectomy. We have studied the remaining sev en cases, which had retinal ischaemia and optic disc or retinal neovas cularization documented by fluorescein angiographic examination. Laser coagulation was applied in these seven cases, which resulted in consi derable regression of the neovascularization and absorption of the vit reous haemorrhage. In one out of the seven cases recurrent vitreous ha emorrhages appeared and it was finally treated by vitrectomy. Visual a cuity improved in six of the seven cases. The follow-up period ranged from 12 to 48 months. The late appearance of the ischaemic type of bra nch retinal vein occlusion with neovascularization can be attributed t o the change in character of the initially mild oedematous form of the disease. Partial posterior vitreous detachment and traction exerted a t some later stage upon the neovascularization could be additional fac tors of the late appearance of vitreous haemorrhage. Patients with bra nch retinal vein occlusion should be followed up regularly over a long period of time in order to avoid late complications of the disease, s uch as vitreous haemorrhage following optic disc or retinal neovascula rization.