Retinal Vein Occlusions
What is a retinal vein occlusion?
A retinal vein occlusion means that a vein in the retina of the eye has become blocked. The retina is the light-sensing tissue at the back of your eye. The veins drain blood out of the retina and return it to the heart.
A blocked vein damages the blood vessels of the retina. Hemorrhages (bleeding) and leakage of fluid occurs from the areas of blocked blood vessels. What are the types of retinal vein occlusion?
There are two types of retinal vein occlusion:
- Central retinal vein occlusion (CRVO)
- Branch retinal vein occlusion (BRVO)
Central Retinal Vein Occlusion: The main retinal vein of the eye is blocked. Blood flow is poor throughout the entire retina. The amount of visual loss varies but is often severe in older peo-ple.
Branch Retinal Vein Occlusion: A smaller branch of the main retinal vein is blocked. Only the part of the retina drained by this branch vein is damaged. Vision loss varies But is not as severe as Central retinal vein occlusion (CRVO).
Who is at risk for retinal vein occlusion?
Retinal vein occlusions are more common in people who have:
- Age-related vascular (blood vessel) disease;
- High blood pressure;
- Blood disorders.
What are the symptoms of retinal vein occlusion?
Blurred vision is the main symptom of retinal vein occlusion. It occurs when the excess fluid leaking from the vein collects in the macula.
The macula is the central area of the retina which is responsible for our central, detailed vision. If the macula swells with excess fluid (macular edema), vision blurs.
Floaters can appear as spots which interfere with vision. When retinal blood vessels are not working properly, the retina may grow abnormal blood vessels (neovascularization) which are fragile. They can bleed or leak fluid into the vitreous—the gel-like fluid that fills the center of the eye—causing the floaters.
Pain in the eye sometimes occurs as a complication of sever CRVO. It is caused by excessive eye pressure called neovascular glaucoma.
What tests might the doctor order?
After a complete eye examination, your ophthalmologist (Eye M.D.) may order blood test and/or a test of the retinal circulation called fluorescein angiography.
What treatment is available?
There is no cure for retinal occlusion. Your ophthalmologist may recommend a period of observation, since hemorrhages and excess fluid may subside on their own.
Laser surgery improves sight in some patients with BRVO and macular edema, but vision does not usually return to normal. Laser surgery is not as helpful in CRVO, but new types of laser surgery are being evaluated.
Laser surgery is very effective in preventing vitreous hemorrhage and neovascular glaucoma. However, it does not remove hemorrhage or cure neovascular glaucoma once they are already present. It is best to treat people at risk for these complications before they occur.
Your ophthalmologist will decide whether laser surgery is appropriate for you. Frequent follow-up examinations are essential. You should make sure that any associated medical condition is treated by your regular physician.
Why are regular medical eye examinations important for everyone?
Eye disease can occur at any age. Many eye diseases do not cause symptoms until the disease has done damage. Since most blindness is preventable if diagnosed and treated early, regular medical eye examinations by an Eye M.D. are very important.