Central retinal vein occlusion
Central retinal vein occlusion (CRVO) occurs when the main vein in the retina at the back of the eye becomes blocked. Central retinal vein occlusion can cause severe loss of vision because it affects the macula at the centre of the retina. The macula provides our central vision, which we rely on to see details, drive, watch television, and more.
Central retinal vein occlusion normally affects one eye and is painless unless you develop complications. The blockage can't be unblocked, but complications can be treated to prevent further loss of vision. Your ophthalmologist will also discuss risk factors that you can manage to limit the chance of central retinal vein occlusion happening in the other eye.
What are the symptoms of central retinal vein occlusion?
Central retinal vein occlusion (CRVO) can cause sudden blurred vision or loss of vision. It's typically painless and affects one rather than both eyes.
There are two types of retinal vein occlusion. Central retinal vein occlusion differs from branch retinal vein occlusion (BRVO) because it affects the main vein at the centre of the retina instead of one of four branch veins. It is more likely to cause severe visual loss, and complications are more likely to occur than with branch retinal vein occlusion.
There are two types of central retinal vein occlusion:
With both types of central retinal vein occlusion, a complication called macular oedema can happen. This is when blood and fluid from the vein that's blocked leaks into the macula, the part of the retina responsible for our central vision. The leakage causes swelling and is associated with a worse visual outcome.
Central retinal vein occlusion treatment
If you have non-ischaemic CRVO, you'll have a follow-up appointment after diagnosis to check for any complications, including macular oedema. If your symptoms get worse in the meantime, speak to your ophthalmologist, don't wait for your next check-up.
If you have ischaemic central retinal vein occlusion, you may need more regular follow-ups due to the higher risk of complications and sight loss.
If you develop macular oedema, treatments for this include:
- Intravitreal injections with anti-vascular endothelial growth factor medication (anti-VEGF), such as Lucentis (Ranibizumab) or Eylea (Aflibercept). Anti-VEGF injections are given at regular intervals, potentially for several years if needed.
- Steroid implant in the eye (Ozurdex, also known as dexamethasone)
The growth of new blood vessels can be prevented with laser treatment called pan-retinal photocoagulation.
Central retinal vein occlusion risk factors
Risk factors include age, with most diagnoses in the over 60s (Source: RCOPHTH), high blood pressure (hypertension), high cholesterol levels, diabetes, and smoking. Many of the risk factors are the same as for cardiovascular disease.
A less common risk factor is having a blood clotting condition.
When to get medical advice
The NHS recommends that everyone has eye exams every two years. As well as checking your eyesight, opticians look at your eye health and can diagnose a range of eye conditions.
An optician or ophthalmologist can do a range of tests to diagnose central retinal vein occlusion. They'll check your visual acuity, field of vision and eye pressure and closely examine your eye with a slit lamp and ophthalmoscope. They may also take a kind of ultrasound image of your eye (called optical coherence tomography or OCT) and use dye injected into your arm that shows up in the veins in your eye (fluorescein angiography).
Living with central retinal vein occlusion
You may feel anxious about being diagnosed and living with central retinal vein occlusion, which can have worse outcomes than branch retinal vein occlusion. You're likely to need regular appointments and possibly treatment over several years. If you get diagnosed with a vision impairment, it's natural to worry about how you'll cope with this.