BRANCH RETINAL VEIN OCCLUSION
What is a branch retinal vein occlusion?
The retina is a layer of light sensitive cells at the back of the eye, which is essential for vision. It converts light into electrical signals, which are sent to the brain through the Optic nerve.
The retina may be damaged if there is a block in the blood vessels which supply the retina.
A block in the veins of the retina may occur either centrally at the optic nerve, when it is known as a Central retinal vein occlusion (CRVO), or only a branch vein is blocked. This is called a branch retinal vein occlusion (BRVO), and it affects only the part of the retina supplied by that particular branch vein.
Who is at risk to develop Branch retinal vein occlusion?
Certain illnesses can increase your risk of developing a retinal vein occlusion:
Diabetes
Hypertension
High cholesterol
Increased eye pressure.
Inflammation in the body
Blood disorders
You may have blood tests done to rule out some of these diseases. We should also have checked your blood sugar and blood pressure if your GP has not already done so.
How it affects your vision:
Some people have no symptoms at all and the condition is picked up by the optician.
Others have a decreased field of vision.
Some patients have more severe central loss of vision. It depends upon where the vein was blocked.
What is the prognosis?
Large studies have shown that 50% of patients get better without any treatment at all. Of course, you should have your blood pressure and blood sugars treated if they are abnormal. This will prevent any more blockages occurring.
Other patients may need to have treatment.
What happens next?
We used to give patients time to get better without treatment. studies are now showing that more rapid treatment with injections into the eye can result in better outcomes Especially if there is a lot of haemorrhage and swelling at the back of the eye . If the blood has cleared and your vision is still blurred (less than 4 lines on the chart) then we may perform a dye test to decide whether your vision can be improved with laser. (We will give you a leaflet on the dye test if you need this).
Three consequences can occur in patients with BRVO:
Water logging of the centre of vision (Macular oedema).
Poor blood supply to the centre of vision (Ischemia).
New blood vessels which can bleed suddenly (Haemorrhage).
a dye test may be given decide whether you have any of these conditions. It will help guide the treatment. We also now carry out scans of the retina to measure the amount of swelling
What is the treatment?
Water logging
If there is water logging but no ischemia (poor blood supply), then you can have laser to improve your vision. However in the last two years new treatments have been approved to treat this condition which may be better than laser or used with laser. These treatments are injections into the eye which can speed up recovery of vision and prevent complications . They are given as am outpatient in a sterile environment . Studies are showing that the sooner you can get treatment the better may be the out come .
New blood vessels
If these are seen clearly you may not need a dye test we will treat them with laser. If they are not detected easily the dye test can help find them.
Poor blood supply to centre of vision (ischemia)
If you have poor blood supply to the centre vision usually we cannot improve the vision. Although magnifiers can help some people. You will usually retain your peripheral vision and the other eye will usually compensate for the loss of vision. You cannot damage your good eye by over use.
The laser treatment
This is offered on a separate day to the dye test.
You can expect to be in the hospital for about 2 hours. It is done in the outpatients’ clinic.
Your eye will be dilated. You will sign consent.
Your eye will be numbed with drops.
The laser is performed at a machine similar to the one you were examined in clinic. It takes about ten minutes. It shouldn’t hurt but afterwards you will feel dazzled for about 20minutes.
The laser will be applied only to those areas that are affected. This minimises damage to healthy tissue.
The laser takes 3-4 months to work. If you have water logging you may either see an improvement in vision or stabilisation in vision.
If you have new blood vessels you can still have a small bleed because it takes time for the treatment to work. But if the bleed occurs it is usually not serious and will disappear with time.
Risks of the laser
The benefits of the laser outweigh the risks. The risks are usually if the laser is damages healthy tissue which could reduce your field of vision or lead to small spots in your vision. These are not usually noticeable with both eyes open. The laser operator will take every precaution possible to prevent these complications
You do not need any drops after the laser and can go back to all your usually activities.
The use of aspirin when you have branch vein occlusion
Aspirin is known to make the blood thinner and lead to more bleeding. If it is not absolutely necessary for you to be on aspirin it is probably better to stop aspirin when you have had a BRVO or Central vein occlusion. This is because it can lead to more bleeding. Once your eye is better (at about 6 months) you can restart aspirin.
New treatments
Injections of steroids and other anti vascular growth factor substances into the eye have been used to treat branch vein occlusion with success however there are some serious side effects the most important one being the development of serious infection or retinal detachment. Other complications include clouding of the lens and a rise in pressure of the eye this may lead to having to have eye drops to treat the pressure or surgery for the pressure ( more rare) Cataracts can be easily treated with surgery.
the injections sound painful and unpleasant but take seconds and we give them after anaesthetic drops so pain will be minimal . However you may need a course of injections and repeat visits and eye scans
If you have anymore questions we have not answered please ask the doctor.
This leaflet was prepared by and Miss T.Richardson, Consultant Ophthalmologist update 2015 February .
