Retinal Venous Occlusion
CRVO (Central Retinal Venous Occlusion) and BRVO (Branch Retinal Venous Occlusion) are retinal diseases caused by outflow obstruction of blood, out of the retina. The resultant increased tissue pressure causes haemorrhages (bleeding) and retinal oedema (water-logging). The degree of ischaemia (or absence of blood circulation) can be variable and worse in CRVO as the entire venous drainage is impeded.
The two complications that can happen as a result are macular involvement (resulting in visual loss) and neovascularisation (abnormal blood vessels causing either bleeding inside the eye resulting in sudden and dramatic visual loss or significantly increased eye pressure causing pain and leading to Glaucoma).