Vascular changes after retinal branch vein occlusion.

I have described the vascular changes after retinal branch vein occlusion and have shown progressive changes both in the large retinal vessels and in the capillary bed. The capillary reactions are comparable to those seen in central retinal vein occlusion. Retinal oedema due to capillary dilatation and leakage occurs in both conditions but, whereas this is generalized in central retinal vein occlusion, local changes occur in branch vein occlusion. Capillary closure also occurs in both conditions, but the neovascular response differs. In branch vein occlusion significant new vessel formation is restricted to the retina leading to recurrent vitreous haemorrhage. This contrasts with central retinal vein occlusion in which thrombotic glaucoma due to predominantly anterior segment neovascularization is the most serious cause of visual loss.