Retinal Artery & Vein Occlusions
We treat all conditions that effect the retina and macula, including wet and dry macular degeneration, diabetic eye disease, retinal artery and vein occlusions, retinal monitoring for hydroxychloroquine, central serous retinopathy, retinal naevi (moles), floaters, and genetic retinal disorders.
Retinal Vein Occlusion
What is a Retinal Vein Occlusion (RVO)?
This occurs when there is a blockage in a vein inside the retina, which is the lining of the back of the eye that acts like the film in a camera. This causes ‘fluid’ to leak into the cells of the retina and can cause reduced vision as a result as the cells cannot function properly.
There are 2 types of RVO
- Branch retinal vein occlusion (BRVO) – obstruction of one of the 4 veins, each of which drains about ¼ of the blood supply to the retina.
- Central retinal vein occlusion (CRVO) – a more severe form usually due to obstruction of the main vein.
This usually occurs in people over 50 years old, although can occur at younger ages. There are some common risk factors other than age;
- High blood pressure
- High cholesterol
Blood disorders making the blood more ‘sticky’. If we think this may be a possibility in your case, we will advise seeing a specialist in blood disorders (haematologist).
What can happen:
- The retinal cells may be damaged by the obstruction to blood flow (retinal ischaemia) – this would need monitoring and possibly retinal laser treatment to stabilise it and prevent further damage to the eye.
- ‘Fluid’ may develop in the center part of the retina, which is the most sensitive part responsible for your vision when you are looking straight at an object. This is called ‘macular oedema’ and there are several treatments available.
Tests we perform:
- Vision, check of eye pressure
- Optical coherence tomography (OCT) – scan of the layers of the retina, very good for detecting ‘fluid’ and other problems
- Photograph of the retina
- Fluorescein angiography – a yellow dye (fluorescein) is injected in your hand or arm and a series of photographs of the retina are taken with you seated at a machine with your chin in a chin-rest. If you need this, we will explain why this is recommended in your case.
Treatments for Macular Oedema
1. Anti-VEGF medicines – Avastin, Lucentis or Eylea
These are given by a injection into the eye and initially need monthly treatment until the vision is improved as far as possible. Injections may then need to be given for some time to keep vision stable but the interval between the injections can usually be extended.
2. Steroid – eg. Ozurdex
Also given as an injection but is an implant (like a small thread) which releases the drug slowly over several months and does not need repeating for 4-6 months.
What can I expect:
50% of patients should gain significant vision.
20-30% may not gain vision but vision should be possible to stabilise.
Side-effects of treatment;
All treatments carry risks. The risk of complications from eye injections is very small and injections would not be recommended if the risk of the treatment was greater than the risk of monitoring without treatment and resulting in reduced vision.
The risk of infection with this treatment is very low but it is very important to report any worsening of the vision or new symptoms – redness, sensitivity to light, pain – that occurs after an injection immediately and if unable to do so by phone, then we would advise attending an Eye Emergency department without delay.
Increased risk of heart attack and stroke – this is very rare and particularly because the injection is only a tiny dose being administered to the eye. However, if you are at risk anyway because you have other risk factors or have had previous heart attacks or stroke, then there may be a small increased risk. We wait for 3-6 months after a known heart attack or stroke before we would advise treatment.
These can cause or increase cataract in the eye although usually only if you have repeated injections, not after a single injection.
May also cause raised eye pressure and we would monitor for this. This occurs in about 25% of patients but only a small number need treatment and usually this is just eye drops which can be stopped once the injection wears off in 4-6 months. Rarely, the pressure may be too high to treat with drops only and a procedure to reduce pressure may be recommended (using laser or very rarely an operation).