Retinal Vein Occlusion
What is a retinal vein occlusion (RVO)?
A blockage (occlusion) of a vein in the retina can lead to sudden painless blurry vision in adults. Veins drain the blood from the eye. When a retinal vein comes temporarily blocked, the blood backs up and leaks into the retinal layers. This blockage causes temporary lack of oxygen to the retina tissues and can lead to permanent retinal damage and secondary vision loss.
What causes a retinal vein occlusion?
Generally the cause of RVO is unknown. Common predispositions or risk factors include:
- High blood pressure
- Cardiovascular risk factors (diabetes, high cholesterol, smoking)
- Rare blood clotting disorders
What can I do to prevent a retinal vein occlusion?
We do not understand why some patients get RVO. The best way to reduce your risk of RVO is by controlling the underlying predispositions listed above. If you have a RVO at a young age (<50 years) and have no other risk factors, then it may be worth doing testing for rare blood clotting disorders with your family doctor.
How do you treat a retinal vein occlusion?
Patients who have RVO should be immediately referred to an ophthalmologist to be monitored for at least 6-12 months and assessed for retinal damage. Patients should also see their family doctor to be assessed for risk factors.
In RVO, the blood spots in the retina will slowly resolve. Sometimes anti-VEGF or steroid medications are used to reduce the tendency for damaged blood vessels to leak. These medications are injected into the vitreous gel in the eye.
Patients with RVO can get chronic swelling of the retina, called macular edema, which causes painless blurry vision.
Macular edema can often be managed with anti-VEGF injections to stabilize the vision. Permanent damage to the retinal blood vessels after RVO may make ongoing anti-VEGF injections necessary to preserve central vision.
Patients with RVO are at risk of a secondary complication where abnormal blood vessels (neovascularization) start to grow on the iris, into the eye’s drainage system, and also on the retina. Neovascularization usually happens in the months after RVO and initially doesn’t cause any vision changes but, if not identified quickly, carries a significant risk of blindness. Neovascularization can only be identified by an eye exam. Neovascularization is a severe condition that requires urgent treatment with laser and sometimes eye injections.