Retinal vein occlusion occurs when one of the tiny retinal veins becomes blocked by a blood clot.Risk factors, apart from advanced age and genetic factors, are smoking, obesity, high blood pressure, diabetes and high cholesterol levels..The occlusion of the vein prevents the drainage of blood which results in haemorrhages and a swelling of the surrounding retina. In the long run the retina is irreversibly damaged.
Retinal vein occlusion is a fairly common cause of vision loss. It is most common in people over the age of 60 and it seems to affect both sexes equally.
The exact reason why a blood clot may form in one of the retinal veins is not clear. However, there are some things that are thought to increase your risk of developing retinal vein occlusion. They include the following
Macular oedema: This is swelling of the macula at the centre of the retina.
Neovascularisation: This is abnormal new blood vessel formation at the back of the eye. About one third of people with retinal vein occlusion develop this problem which can sometimes lead to increased pressure within the eye and to glaucoma. Also, the new blood vessels are of a poor quality and can sometimes bleed.
If you have retinal vein occlusion, you will usually notice painless decrease in vision in one eye or blind spot in one eye. Depending on the severity and also the degree of involvement of the macula, retinal vein occlusions may cause only mild visual loss. However, in some cases they may cause very profound visual loss.
Retinal vein occlusion is usually diagnosed after an eye specialist (an ophthalmologist) examines the back of your eye, using an ophthalmoscope. The retina at the back of your eye has a typical appearance in retinal vein occlusion. Your specialist may advise some other tests or examinations to help to see how much damage has occurred to your retina. The tests may include:
Currently, there is no treatment that can reverse the blocked vein. The aims of treatment are to detect and treat any underlying risk factors for the condition and also to detect and treat any complications where possible.Treatment of any complications
Someone with retinal vein occlusion needs close follow-up so that any complications can be picked up early and treated where possible.
Anti-VEGF therapy involves the injection of the medication into the back of your eye. The medication is an antibody designed to bind to and remove the excess VEGF (vascular endothelial growth factor) present in the eye that is causing the disease state. The FDA has approved Lucentis for macular edema and additional treatment options include Avastin and Ozurdex.
Following a retinal vein occlusion you are likely to be left with some visual loss. The extent of the visual loss can vary greatly, depending on the severity and exact site of the vein occlusion. Early diagnosis and treatment of retinal vein occlusion and any complications may make a difference to the eventual level of visual loss. However, severe vein occlusions can cause permanent visual loss, even if treated very early. Retinal vein occlusion will recur in about 1 in 6 people (either in the same eye or in the other eye) over the five years following on from
Dr. Shrutika Kankariya
Retina & Diabetes Eye Specialist MBBS (KEM,Mumbai), DNB (Sankara Nethralaya, Chennai),FRCS(Glasgow), FICO(UK), Fellow Retina (Sankara Nethralaya & USA),