What is it about ?
In the retina, there are three types of blood vessels: arteries, veins, and optic nerve blood vessels. The arteries supply the eyes with oxygen-rich blood, and after the oxygen diffuses, the veins return the blood to the heart. The optic nerve carries information from the retina to the brain. When a blood clot stops the flow of blood to a blood vessel, it is called thrombosis.
There are three types of ocular thrombosis depending on the blocked blood vessel:
- Blocked vein: venous thrombosis,
- Clogged artery: arterial thrombosis,
- Obstruction of an optic nerve blood vessel: optic nerve infarction, medically called “anterior ischemic optic neuropathy” (NOIA) (“ischemia” means “insufficient blood flow”).
In this patient guide, we are only talking about retinal vein thrombosis, which is a blood clot in a vein in the retina.
All of the small veins join together in a large vein that runs along the optic nerve. In the event of thrombosis in a vein, blood can no longer leave the retina. As the blood is blocked, it causes the vein to leak. Passing through the wall of the vein, blood, which contains fluid and protein, enters the retina, causing deterioration of vision.
If a small vein is obstructed, it is called a “branch retinal vein occlusion (OBVR)”; if the central vein is obstructed, it is called “central retinal vein occlusion (CRVO)”, which is accompanied by bleeding and leakage throughout the retina.
The blood that remains in place then causes engorgement, which makes it difficult to supply fresh blood. This causes a lack of oxygen in the retina. In response, the retina secretes substances necessary for the growth of new blood vessels. These new blood vessels are unfortunately very fragile and bleed easily. Sometimes new blood vessels develop on the iris or in the anterior chamber. In this case, the pressure inside the eye increases, which can cause glaucoma.
Where and how often?
Retinal vein thrombosis is the most common cause of blood vessel problems in the retina. This disease is more common in smokers and in people who have high blood pressure, too much cholesterol, diabetes, or too much pressure in the eye (glaucoma). People with a bleeding problem are also more at risk of developing venous thrombosis.
Retinal vein thrombosis usually affects people over 65 years of age; it is as common in women as in men. Each year, it affects 5 in 1,000 people.
How to recognize it?
With retinal vein thrombosis, vision deteriorates in one eye over a period of hours or days, without pain. Symptoms depend on the severity of the blockage as well as where the blocked blood vessel is. Symptoms may be blurred vision, a blemish in the field of vision, and may go as far as being difficult to distinguish hand movements.
How is the diagnosis made?
The doctor will take your blood pressure and possibly do a blood test (to test your cholesterol and sugar levels and to look for bleeding disorders). If he suspects thrombosis based on your symptoms, he will urgently refer you to an ophthalmologist for a thorough eye exam and treatment.
What can you do ?
In the event of thrombosis, there is nothing you can do on your own. Contact the general practitioner without delay.
Adopt a healthy lifestyle to prevent a (new) thrombosis: for example, exercise regularly, eat healthy and do not smoke.
What can the doctor do?
In the acute phase (when the thrombosis is very recent), the general practitioner will refer you to an ophthalmologist. This will determine if treatment is possible. Treatment usually consists of an injection of cortisone or growth inhibitors into the vitreous body (into the eyeball). This reduces the formation of new blood vessels and the accumulation of fluid. Laser treatment of the retina may also be considered. This treatment aims to prevent bleeding from new, fragile vessels.
Aspirin is started in all cases (except contraindication). If there are signs of a coagulation disorder, anticoagulants are administered.
At a later stage, it is essential that the general practitioner performs a general examination. He can thus check whether there are factors (arterial hypertension, diabetes, high cholesterol level, etc.) that can be taken care of to reduce the risk of new thrombosis.
Want to know more?
- Stop smoking. It’s possible – Tabacstop
- The food pyramid – Eat Move – Health Question
- Physical activity – Eat Move – Health question
Are you looking for more specialized help?
- Smoking Assistance Center (CAF®) – FARES – Respiratory Affections Fund
- Tobacco specialists – FARES – Respiratory Affections Fund
- Find a registered dietitian – Professional Union of French-speaking dieticians
- Find a nutritionist doctor – Belgian Society of Nutritionist Doctors
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