A retinal vein occlusion is a blockage of the blood vessels that feed the retina and can result in sudden and serious vision problems.
The retina is the nerve layer that lines the back of the eye. Like every other tissue in the body, the retina is nourished by a system of blood vessels.
The retinal arteries and veins originate in the optic nerve, and spread across the entire retina. Sometimes a clot, or an obstruction to blood flow, can occur in a retinal vein.
This clot or obstruction can affect the entire retina if it occurs at the central vein, where the optic nerve is – or it may affect a portion of the retina if it occurs further out from the center. This condition is called retinal vein occlusion. Typically, a retinal vein occlusion will cause fluid or blood to build up in the affected parts of the retina, including the part of the retina that provides sharp vision, called the macula.
Retinal vein occlusion can cause sudden and severe blurring, or dimming of vision. Over time, these acute symptoms may turn into permanent visual loss. Retinal vein occlusion needs prompt attention by an eye doctor, because in many cases, treatment can be provided to reduce swelling of the macula, and to prevent other complications.
Retinal vein occlusion symptoms
Just as a stroke can occur suddenly and without warning, symptoms of a retinal vein occlusion or ‘eye stroke’ usually occur quite suddenly. A sudden loss of vision or sudden blurring of vision is often the first sign that many people are aware of. The severity of symptoms differs from person to person and also depends on whether the blockage is to the central or a branch vein.
A branch retinal vein occlusion (BRVO) refers to a blockage of the smaller retinal veins. This usually results in blurred vision or a missing area of vision. Many people with a BRVO find that their vision gradually improves again over time as the eye naturally heals itself.
A central retinal vein occlusion (CRVO) is more serious and usually involves a more severe loss of vision.
Causes of retinal vein occlusions
Just like a stroke causes damage to other parts of the body when blood circulation fails, a retinal vein occlusion causes damage to the eye. When the blood flow to the retina is blocked, oxygen and nutrients cannot reach it and a haemorrhage occurs.
A retinal vein occlusion usually occurs because of a hardening of the arteries which causes a clot. The following factors put people most at risk of a retinal vein occlusion:-
- High blood pressure
- High cholesterol
Retinal vein occlusions are most common in people over 60 years of age.
Retinal vein occlusion treatment
Treatment for retinal vein occlusions depends on their type and severity, and can include: laser treatment, injections or a vitrectomy. A BRVO may not require any treatment and may heal itself given time. A CRVO, on the other hand, may require immediate treatment.
If you are diagnosed with a retinal vein occlusion, you should also visit your GP for a check-up as you may be more at risk of clotting and circulation problems in other parts of your body.