Understanding Retinal Vein Occlusion: Symptoms and Treatment

Retinal vein occlusion (RVO) is a blockage in one of the veins that drains blood from the retina, and it’s the second most common cause of vision loss from retinal blood vessel disease after diabetic retinopathy. It usually shows up as sudden, painless blurring in one eye, and it’s most common in people over 50 who have high blood pressure, high cholesterol, or diabetes. Treatment has changed a lot in the last few years — anti-VEGF injections are now the first choice for the swelling that threatens vision. 

What Is Retinal Vein Occlusion?

Your retina, the light-sensing tissue at the back of the eye, depends on a network of small veins to carry blood away after it’s been used. When one of those veins gets blocked, blood backs up. Pressure builds, fluid leaks, and sometimes the vessel bleeds. The retina can’t function properly under those conditions, which is why vision drops.

Doctors classify RVO by where the blockage sits:

• Central retinal vein occlusion (CRVO): the blockage is in the main vein at the optic nerve, so the whole retina is affected. This tends to cause the most severe vision loss.
• Branch retinal vein occlusion (BRVO): the blockage is in one of the smaller branches, so only part of the visual field is affected. BRVO is more common, showing up in roughly 6 to 12 out of every 1,000 people.
• Hemiretinal vein occlusion (HRVO): a less common variant where roughly half the retina is affected, falling somewhere between CRVO and BRVO in severity.

Symptoms of Retinal Vein Occlusion

The hallmark symptom is sudden or gradually worsening blurry vision in one eye, without pain. Some people wake up with noticeably worse sight; others notice it creeping in over a few hours or days.

Other symptoms to watch for include:

• Dark spots, floaters, or lines drifting across your vision
• A blind spot or missing section of your visual field, especially with BRVO
• Eye pressure or discomfort, usually a sign of a more advanced case
• No symptoms at all in mild cases — some people only find out during a routine eye exam

Because RVO is painless in most cases, it’s easy to dismiss early symptoms as fatigue or eye strain. Any sudden change in vision in one eye deserves a same-week visit to an eye doctor, and same-day if the change is significant, since delayed treatment allows more permanent damage to build up.

What Causes It, and Who’s at Risk

Retinal Vein Occlusion develops when blood flow through the retinal vein slows or stops, usually because the vein gets compressed by a stiffened, adjacent artery, or because a clot forms inside it. The risk factors overlap heavily with cardiovascular disease:

• High blood pressure
• High cholesterol
• Diabetes
• A history of heart attack, stroke, or glaucoma
• Smoking
• Less commonly, clotting disorders in younger patients

This overlap matters beyond the eye. People diagnosed with any type of RVO have a measurably higher risk of future cardiovascular events and death from any cause, according to the American Academy of Ophthalmology’s retina practice guidelines. An RVO diagnosis is often a signal to get blood pressure, blood sugar, and cholesterol checked and managed, not just an eye problem to treat in isolation.

How RVO Is Diagnosed

An eye doctor can usually spot RVO during a dilated eye exam — the retina shows a characteristic pattern of bleeding and swollen veins. To confirm the diagnosis and plan treatment, they’ll typically add:

• Optical coherence tomography (OCT): a scan that measures retinal thickness and detects the fluid buildup, or macular edema, that drives most vision loss.
• Fluorescein angiography: dye injected into the arm highlights blood flow and shows areas of the retina that aren’t getting enough oxygen.
• Blood pressure and lab work: to check for underlying diabetes, high cholesterol, or clotting problems.

Treatment Options for Retinal Vein Occlusion

The first-line treatment for vision-threatening macular edema from RVO is an anti-VEGF injection directly into the eye, according to the 2025 American Academy of Ophthalmology Preferred Practice Pattern. These medications block a protein that drives abnormal fluid leakage and blood vessel growth, and for most patients they’re started as a series of monthly injections that get spaced out as the retina stabilizes.

Other treatments come into play depending on the case:

• Intravitreal corticosteroids: work well for swelling but carry a higher risk of raising eye pressure or accelerating cataracts, so they’re usually a second-line option.
• Laser photocoagulation: is still used for BRVO, particularly to treat abnormal new blood vessels or persistent edema that doesn’t fully respond to injections.
• Managing the underlying conditions:  blood pressure, blood sugar, cholesterol — happens alongside eye treatment, usually coordinated with a primary care doctor.

None of these treatments reverse damage that’s already occurred, which is why timing matters. Starting anti-VEGF therapy early, while the retina is still swollen but not yet permanently scarred, gives the best shot at recovering vision.

Outlook and What to Expect

Recovery varies a lot by type and severity. BRVO tends to have a better visual outcome than CRVO, and patients who start treatment early generally do better than those who wait. Even with treatment, some patients need ongoing injections for years to keep swelling controlled, and regular follow-up imaging is standard to catch complications like neovascular glaucoma before they become serious.

Frequently Asked Questions

Is retinal vein occlusion an emergency?
It’s not a same-hour emergency the way a retinal detachment can be, but sudden vision loss in one eye should be evaluated by an eye doctor within a day or two. Delaying treatment for macular edema allows more permanent retinal damage.

Can retinal vein occlusion be reversed?
Vision can improve substantially with prompt anti-VEGF treatment, especially in BRVO, but damage already done to the retina generally can’t be fully reversed. Early treatment gives the best chance at recovering lost vision.

Does retinal vein occlusion affect both eyes?
It’s usually confined to one eye at a time. Having RVO in one eye does raise the risk of developing it in the other eye eventually, particularly if underlying risk factors like high blood pressure go unmanaged.

What is the difference between CRVO and BRVO?
CRVO blocks the main retinal vein and affects the entire retina, usually causing more severe vision loss. BRVO blocks a smaller branch vein and affects only part of the visual field, generally with a better long-term outlook.

How often are anti-VEGF injections needed for RVO?
Most patients start with monthly injections while swelling is active, then move to a less frequent schedule as the retina stabilizes.

Medically reviewed by Dr Tan