Retinal Vein Occlusion: Causes, Treatment, and Recovery
Understanding Retinal Vein Occlusion
Retinal vein occlusion (RVO) happens when a vein in the retina becomes blocked. The retina needs a steady supply of blood to function. Arteries bring oxygen-rich blood to the retina, and veins carry blood back out. When a vein is blocked, blood backs up and leaks into surrounding retinal tissue. This causes swelling, bleeding, and reduced oxygen supply to retinal nerve cells.
RVO is the second most common retinal vascular disease, behind only diabetic retinopathy. Approximately 16.4 million adults worldwide are affected by RVO (Rogers et al., Ophthalmology, 2010).
There are two main types of retinal vein occlusion, based on which vein is affected.
- Branch retinal vein occlusion (BRVO) occurs when a smaller branch vein in the retina is blocked. BRVO is the more common type. Approximately 13.9 million adults globally are affected by BRVO (Rogers et al., Ophthalmology, 2010).
- Central retinal vein occlusion (CRVO) occurs when the main vein draining the entire retina becomes blocked. CRVO is less common but often more severe. About 2.5 million adults globally are affected by CRVO (Rogers et al., Ophthalmology, 2010).
Most branch retinal vein occlusions happen at an arteriovenous crossing. This is a spot where a retinal artery and vein cross over each other. The artery can press on the vein, narrowing it and causing turbulent blood flow. This turbulence promotes clotting, which leads to the blockage.
Central retinal vein occlusion develops from a blood clot or reduced flow in the central retinal vein. The process generally involves three factors: slowed blood flow, damage to the vessel wall, and increased clotting tendency. When the vein is blocked, oxygen levels drop in the retina. This triggers the release of vascular endothelial growth factor (VEGF), a protein that causes fluid leakage and abnormal blood vessel growth.
RVO can lead to serious complications if not treated promptly. The most common complication is macular edema, which is swelling in the center of the retina. The macula is responsible for sharp, detailed central vision. When it swells, vision becomes blurry or distorted.
In more severe cases, the lack of oxygen to the retina (called ischemia) can trigger abnormal new blood vessel growth. This process, called neovascularization, can lead to vitreous hemorrhage (bleeding into the gel inside the eye). It can also cause neovascular glaucoma, a painful condition from increased eye pressure.
Who Is Affected and Risk Factors
The overall prevalence of RVO in the United States is approximately 0.50%, with BRVO at 0.42% and CRVO at 0.08% (NHANES, 2005-2008). BRVO occurs six to seven times more commonly than CRVO. The 10-year cumulative incidence was 0.64% for BRVO and 0.14% for CRVO (Gutenberg Health Study, AAO, 2025).
Older age is the most important risk factor for both BRVO and CRVO. Over 90% of retinal vein occlusion cases occur in patients over the age of 55 (AAO, 2025). For every 10-year increase in age, the odds of developing RVO nearly double (OR 1.93; Gutenberg Health Study, AAO, 2025).
Hypertension (high blood pressure) is the strongest systemic risk factor for retinal vein occlusion. People with high blood pressure have nearly three times the odds of developing RVO (meta-OR 2.82; Rogers et al., Ophthalmology, 2010). Cardiovascular disease also raises the risk of RVO. Conditions affecting blood vessels throughout the body can contribute to the vessel wall changes and blood flow problems that lead to vein blockages in the retina.
Several additional conditions are associated with a higher risk of retinal vein occlusion.
- Diabetes increases the risk of blood vessel damage throughout the body, including in the retina.
- Glaucoma (a condition involving increased eye pressure) has been linked to a higher risk of RVO.
- Increased body mass index (BMI) is associated with higher RVO risk.
- Elevated diastolic blood pressure is an independent risk factor. For every 10 mm Hg increase, the odds of RVO rise significantly (OR 1.47; Gutenberg Health Study, AAO, 2025).
Signs and Symptoms
The most common symptom of retinal vein occlusion is a sudden, painless change in vision. Many people notice blurry or distorted vision that comes on quickly, often over hours or a few days. The vision change typically affects only one eye.
In BRVO, the vision loss may affect only part of the visual field, depending on which branch vein is blocked. In CRVO, the vision loss tends to be more widespread because the main vein is affected.
Some people with RVO notice an increase in floaters. These are dark spots, lines, or cobweb-like shapes that drift across the field of vision. In rare cases, floaters from a vitreous hemorrhage may be the first sign of a vein occlusion that was not previously detected.
Most retinal vein occlusions are painless. However, patients with severe CRVO who develop neovascular glaucoma may experience eye pain, redness, and irritation. These symptoms indicate a serious complication requiring urgent attention.
If you experience sudden blurry vision, a sudden increase in floaters, or any sudden vision loss in one eye, see a retina specialist or go to the emergency room immediately. Early evaluation is critical for protecting your remaining vision.
Diagnosis and Testing
A retina specialist will begin with a comprehensive dilated eye examination. Special drops widen the pupil so the retina can be seen clearly. The specialist looks for signs of vein blockage, including swollen veins, hemorrhages, and cotton-wool spots (white patches indicating reduced blood flow).
The appearance of the retina often gives a clear indication of whether BRVO or CRVO is present and how severe the condition is.
Optical coherence tomography (OCT) is a non-invasive imaging test that creates detailed cross-sectional pictures of the retina. OCT allows the retina specialist to measure macular thickness and detect macular edema. This test is essential for determining whether fluid has built up in the central retina and for tracking treatment response over time.
Fluorescein angiography is a diagnostic test in which a special dye is injected into a vein in the arm. As the dye travels through retinal blood vessels, a camera takes rapid photographs. This test reveals areas of blocked blood flow, leaking vessels, and abnormal new vessel growth. It helps the retina specialist determine the extent of the occlusion and plan treatment.
Because retinal vein occlusion is closely linked to systemic health conditions, blood tests may be recommended. These check for high blood pressure, diabetes, high cholesterol, and blood clotting disorders. Younger patients or those without typical risk factors may need additional testing. Coordinating care with a primary care physician is an important part of managing the condition.
Treatment Options
Anti-VEGF injections are the primary treatment for macular edema caused by retinal vein occlusion. These medications block VEGF, a protein that drives fluid leakage and abnormal blood vessel growth. The medications are delivered as intravitreal injections (injections directly into the eye).
Lucentis (ranibizumab) was the first anti-VEGF drug approved to treat RVO, receiving FDA approval in 2010. Eylea (aflibercept) was approved by the FDA in 2014 for macular edema from both BRVO and CRVO. It is typically given every 4 to 8 weeks after an initial loading phase. Vabysmo (faricimab), a bispecific antibody targeting both VEGF and angiopoietin-2, received FDA approval for RVO in 2023.
Avastin (bevacizumab) is also commonly used to treat RVO. Avastin is FDA-approved for cancer treatment and is used off-label for eye conditions. Despite its off-label status, it has extensive clinical data supporting its use in RVO.
For patients with chronic macular edema that does not respond well to anti-VEGF therapy, steroid implants may be an option. Ozurdex (dexamethasone implant) was approved by the FDA in 2009 for macular edema following RVO. It is injected into the eye and slowly releases medication over several months.
Steroid treatments can be effective but carry risks including increased eye pressure and cataract formation. A retina specialist will weigh these risks against the potential benefits for each patient.
Laser photocoagulation (thermal laser applied to the retina) was once the standard treatment for BRVO. Anti-VEGF injections have largely replaced laser as first-line treatment. However, laser therapy may still be used in certain situations. It can help reduce macular edema in BRVO and treat areas of abnormal new blood vessel growth.
Treating the retinal vein occlusion itself is only one part of care. High blood pressure, diabetes, and cardiovascular disease are major risk factors. Controlling blood pressure, blood sugar, and cholesterol levels can help reduce the risk of further vein occlusions. A retina specialist will often coordinate with a primary care physician to address systemic health.
What to Expect
Treatment typically begins with a series of anti-VEGF injections at regular intervals, often monthly for the first few months. This initial loading phase helps reduce macular edema and stabilize vision. After the loading phase, the retina specialist may extend the time between injections based on the eye's response.
Intravitreal injections are performed in the office. The eye is numbed with anesthetic drops before the injection. Most patients feel pressure or mild discomfort, but the injection itself takes only a few seconds.
The visual outcome varies depending on the type and severity of the occlusion, how quickly treatment begins, and overall retinal health. Many patients with BRVO experience meaningful improvement with prompt anti-VEGF treatment. Patients with CRVO may have more variable outcomes, especially if significant ischemia is present.
It is important to have realistic expectations. Some patients regain much of their lost vision, while others may see partial improvement. In some cases, treatment may stabilize vision and prevent further decline. Consistent follow-up with a retina specialist is critical for the best possible outcome.
Retinal vein occlusion requires ongoing monitoring, even after vision has stabilized. Macular edema can recur, and new complications can develop over time. Regular visits to a retina specialist allow for early detection and prompt treatment. Some patients need continued injections for months or years to maintain their vision.
Living With Retinal Vein Occlusion
Because retinal vein occlusion is closely tied to systemic health, managing blood pressure, blood sugar, and cholesterol is important. Regular exercise, a balanced diet, and taking prescribed medications as directed can help reduce the risk of complications and recurrence. Quitting smoking is also strongly recommended, as smoking damages blood vessels throughout the body.
Some people living with retinal vein occlusion may notice lasting changes in their vision, even with treatment. Low-vision aids such as magnifying devices, large-print materials, and improved lighting can help with daily tasks. A retina specialist can provide guidance on available resources for vision rehabilitation.
Having retinal vein occlusion in one eye increases the risk of developing it in the other eye. Regular comprehensive eye exams are important for catching early signs of a new vein occlusion. Report any sudden vision changes in either eye to a retina specialist right away.
When to See a Retina Specialist
Certain symptoms require immediate attention. See a retina specialist or go to the emergency room immediately if you experience any of the following.
- Sudden blurry or distorted vision in one eye
- Sudden painless loss of vision
- A sudden increase in floaters
- A dark curtain or shadow moving across your field of vision
If you have high blood pressure, diabetes, cardiovascular disease, glaucoma, or a history of retinal vein occlusion, regular retinal exams can help detect problems early. Early detection and prompt treatment offer the best chance of preserving vision. A primary care physician or optometrist can screen for retinal problems and refer you to a retina specialist if needed.
Questions and Answers
Retinal vein occlusion most commonly affects one eye at a time. However, having RVO in one eye does increase the risk of developing it in the other eye. This is especially true if underlying risk factors like high blood pressure or diabetes are not well controlled. Regular monitoring of both eyes by a retina specialist is recommended.
The duration of treatment varies from person to person. Some patients need injections for several months, while others may require ongoing treatment for a year or longer. A retina specialist will tailor the treatment schedule based on how the eye responds. Newer medications like Vabysmo may allow for longer intervals between injections in some patients.
Retinal vein occlusion shares many of the same risk factors as stroke and heart disease. These include high blood pressure, diabetes, and high cholesterol. While RVO itself is not a stroke, it is a vascular event in the eye. A diagnosis of RVO is a signal to evaluate cardiovascular risk factors with a primary care physician.
Visual recovery depends on the type and severity of the occlusion, the amount of retinal damage, and how quickly treatment begins. Some patients experience significant improvement, while others may have lasting vision changes. Anti-VEGF treatment has greatly improved outcomes compared to earlier treatments, but results vary. Consistent follow-up and adherence to the treatment plan give the best chance of a favorable outcome.
Managing systemic health conditions is the most effective way to reduce the risk. Keeping blood pressure, blood sugar, and cholesterol within healthy ranges through diet, exercise, and medication can help protect retinal blood vessels. Maintaining a healthy weight and avoiding smoking are also important steps. While these measures cannot eliminate risk entirely, they can significantly lower it.