What it is
In short: a retinal vein occlusion is a blocked vein in the retina, the layer at the back of the eye that senses light. It can blur the sight in one eye, sometimes suddenly. Treatment is aimed at the effects of the blockage, such as swelling at the back of the eye.
Veins carry blood away from the retina. When one is blocked, blood and fluid can leak into the retina. This can cause swelling and affect your vision.
There are two main types:
- Branch retinal vein occlusion: a smaller vein is blocked, affecting part of the retina.
- Central retinal vein occlusion: the main vein draining the retina is blocked.
The name tells you where the blockage is. How much it affects your sight also depends on the swelling, and on how much of the retina has poor blood flow.
Retinal vein occlusion is linked to:
- high blood pressure
- high cholesterol
- diabetes
- smoking
- glaucoma
Sometimes no single cause is found. Your eye findings may mean your general health needs checking too, as well as treatment or monitoring of the eye.
Symptoms
Your vision may become blurred or dim in one eye, sometimes suddenly. If the macula, the centre of the retina, swells, reading or recognising faces can become hard, and lines may look distorted. A branch blockage away from the centre may cause few symptoms and only be found during an eye examination.
The first loss of vision may happen without pain. Later problems can include:
- bleeding inside the eye, seen as floaters or haze
- abnormal new blood vessels at the front of the eye. These can block the eye's drainage, raising the eye pressure and causing pain or redness.
Any change in your symptoms needs checking, even after you have been diagnosed.
When it is urgent
Get urgent help if your sight suddenly drops or gets much worse. You cannot tell the cause at home, and other causes of sudden sight loss need emergency care. Also get checked quickly for:
- a painful red eye with blurred vision
- new floaters with a shadow
Call the clinic at +65 6694 0400. Outside clinic hours, call the 24-hour answering service at +65 6535 8833, or go to a hospital A&E with eye services. If you are having injections, report any increase in pain, redness or blurred vision after an injection straight away. Do not wait for your next appointment.
What the assessment involves
Dr Chin will check your vision, eye pressure and retina, usually after drops to widen your pupils. The drops take 20 to 30 minutes to work and blur your sight for a few hours. Allow about 90 minutes to two hours for the visit, and arrange for someone to drive you home.
The pattern of bleeding and vessel changes shows whether a branch or the central vein is blocked. Dr Chin also looks for abnormal new vessels and other problems.
An OCT scan uses light to take detailed pictures of the macula and measure any swelling. A test called fluorescein angiography may also help. A dye is injected into a vein in your arm, and photographs show it flowing through the blood vessels of the retina. This shows leaks and areas with poor blood flow. It is only done when the extra information will help guide your care.
Your blood pressure may be checked, and blood tests arranged with your usual doctor. Whether you need tests for blood clotting depends on your age, your medical history and whether both eyes are affected. Not everyone needs the same tests.
Treatment options
Treatment is aimed at the effects of the blockage, mainly swelling of the macula and abnormal new vessels. It does not remove a clot from the eye. If there are no problems that need treatment, regular planned checks may be all you need.
- Anti-VEGF injections: used for macular oedema, which means swelling of the centre of the retina. VEGF (vascular endothelial growth factor) is a signal in the eye that drives leaking and the growth of abnormal blood vessels. The medicine blocks it. The eye is cleaned and numbed, then the medicine is injected into it. You may need repeat injections, timed according to your vision and scan results.
- Steroid injections or a slow-release steroid implant: an alternative for some eyes. Steroids can raise the eye pressure and lead to cataract, so these risks are weighed up.
- Laser: used when abnormal new vessels develop, and sometimes for certain patterns of swelling. Dr Chin will explain the reason for laser separately from the reason for injections.
Injections also have risks, such as infection, inflammation and problems with the retina.
Recovery and follow-up
Retinal vein occlusion often needs repeated checks. Fluid can come back after treatment, and abnormal new vessels can appear later. A spell without symptoms does not mean checks can stop. At follow-up visits, Dr Chin may check your vision, eye pressure and retina, with an OCT scan when needed.
Keep up the care for your blood pressure, cholesterol, diabetes and glaucoma, as advised by the doctors who manage them. If you smoke, ask about help to stop. These steps are part of managing the risks linked to the condition, but they do not replace eye treatment.
There is no fixed recovery timetable. The damage to the retina and the pattern of swelling differ from eye to eye. If reduced vision still affects your daily life, ask about visual aids and practical support.
Related articles
Sources
- American Society of Retina Specialists: Branch retinal vein occlusion
- American Society of Retina Specialists: Central retinal vein occlusion
- Guy's and St Thomas' NHS: Retinal vein occlusion
- East Lancashire Hospitals NHS: Retinal vein occlusion
- American Society of Retina Specialists: Intravitreal injections