Retinal Vein Occlusion
If the flow of blood in the veins stops or slows for any reason, spots of blood and protein may leak out of the vein and into the retina and this can affect vision.
The symptoms are variable and range from mild to severe visual loss depending on the size and site of the blocked vein. Leakage of fluid from the blocked vein causes swelling of the surrounding retina thus blurring the vision. Sometimes the flow of blood stops completely and then parts of the retina die so that vision is severely affected.
Loss of vision may happen suddenly or gradually. Sometimes the problem is not noted until the good eye is covered for some reason or until a doctor or looks into the eye.
Sometimes it is the main (central) vein that is affected, sometimes only one of its branches.
What causes RVOs?
Several factors can cause an occlusion in the retinal vein:
Anything that makes the blood too thick or sticky eg.
- Smoking cigarettes
- Pressure on the vein from a hardened retinal artery due to high blood pressure
- High pressure in the eye
- High cholesterol or lipids Diabetes
- Inflammation in the eye
What treatment is available?
It is very important to prevent another episode of vein blockage in either eye so your blood pressure will be measured and you will be asked to have blood tests to identify any cause of the vein occlusion.
If new blood vessels are growing on the iris or retina then laser treatment is necessary to try and help shrink these vessels.
If there is swelling of the central retina (macula) then laser treatment to this area may reduce the swelling.
Trials of newer treatments such as injections of steroids or other drugs are being tried to see if they improve the longer-term outcomes in vein occlusions.