The retina of the eye is fed by an inflow of blood, oxygen and nutrients. When the veins of the retina are blocked, retinal venous occlusion may appear.
Central venous occlusion of the retina (CRVO) is clogging of the main vein of the artery. When fluid is accumulated in the macula (the zone of the retina responsible for central vision), vision gets blurred.
There are two types of CRVO:
- Non-ischemic – the lighter type of CRVO
- Ischemic CRVO – this is the more serious type of CRVO. It can cause the development of significant complications. Loss of vision is possible.
The most common symptom of CRVO is blurring or loss of vision in the whole or part of one eye. Blurring or loss of vision is painless and develops over a few hours or days. Sometimes, full and sudden loss of vision is present.
Blurred spots in the vision field are another symptom of CRVO. In heavy cases of CRVO, the blocked vein can cause painful pressure in the eye.
Ischemic CRVO can also cause neovascular glaucoma. This type of glaucoma occurs when abnormal blood vessels start growing in the deep structures of the eye, which causes an increase in ocular pressure. Neovascular glaucoma is a serious condition which causes pain and can lead to heavy vision loss.