The retina is the layer of tissue present at the back of the eye. It changes the light that enters the eye into nerve signals, which are transmitted to the brain for interpretation. Blood vessels supply oxygen and nutrients to the retina to keep it in working condition. As you age, atherosclerosis (hardening or thickening) and clot formation can occur in these vessels. These blocked arteries cross over retinal veins, exerting pressure on them and disrupting the flow of blood. A block in these veins that carry blood away from the retina can lead to a condition known as retinal vein occlusion (RVO). There are two types:
- Central retinal vein occlusion (CRVO): The block occurs in the central/main retinal vein.
- Branch retinal vein occlusion (BRVO): The block occurs on the surface of the retina, where the main retinal vein branches into smaller veins.
The elderly are most often affected by retinal vein occlusion. The condition may be painless and often occurs in only one eye. Symptoms include sudden blurring or loss of vision, which worsens over time. Some patients may experience complete loss of vision.
Some of the risk factors for retinal vein occlusion include high blood pressure, diabetes, hypercholesterolemia, atherosclerosis, and smoking
Vein occlusion can be treated with:
- Intravitreal anti-VEGF Injection
- Intravitreal steroid injection or implant
- Macular Laser
- Panretinal Photocoagulation
When left untreated, retinal vein occlusion can lead to further complications such as macular oedema (fluid build-up in the macula, present in the center of the retina) and neovascularisation (growth of new abnormal blood vessels in the retina) leading to further worsening of vision.