What is retinal vein occlusion?
The retina has its own circulation — small arteries that bring blood in, and small veins that carry blood back out. A retinal vein occlusion happens when blood flow through one of these outflow veins slows enough that blood and fluid back up behind it. The fluid leaks into the retina and causes swelling — often involving the macula, the central part of the retina responsible for sharp vision. Sluggish flow can develop where a thickened, hardened artery presses on a vein, or as a result of other vascular changes that come with age, high blood pressure, and diabetes.
A vein occlusion typically causes sudden, painless vision loss in the affected eye. The amount of vision lost depends on which vein is affected and how much of the retina is involved.
Symptoms
The most common symptom is a sudden, painless drop in vision in one eye. Some patients describe it as a blur, a smudge, or a missing area in their visual field. There is usually no warning. Less commonly, vision loss develops over hours or days rather than all at once.
If you experience sudden vision changes in one eye, you should be evaluated promptly.
Risk factors
Retinal vein occlusion shares risk factors with other vascular diseases. The most common are:
- High blood pressure
- Diabetes
- High cholesterol
- Glaucoma or elevated eye pressure
- Smoking
Less commonly, vein occlusions in younger patients can be associated with clotting disorders or inflammatory conditions, which may warrant additional workup.
How we diagnose it
A complete evaluation includes a dilated examination, optical coherence tomography (OCT) imaging to measure macular swelling, and — when indicated — fluorescein angiography or OCT angiography to identify areas where blood flow has been lost. Because vein occlusion is often a sign of underlying systemic disease, we will also recommend follow-up with your primary care doctor.
Treatment options
Treatment is aimed at the swelling and abnormal blood vessel growth that vein occlusion causes.
Intravitreal injections. Anti-VEGF medications are the most common treatment for the macular swelling that causes vision loss. Intravitreal steroids are an alternative in select cases. Most patients require ongoing injections on a personalized schedule.
Laser treatment may be used in select cases, depending on the extent of the occlusion and how the eye responds to other therapies.
Vitrectomy is occasionally needed for complications such as non-clearing vitreous hemorrhage.