Retinal Vein Occlusion: Risk Factors and Injections Explained

Imagine waking up one morning and noticing your vision is blurry - not like you’re tired, but like someone smeared grease across your glasses. No pain. No warning. Just sudden, silent vision loss in one eye. That’s what retinal vein occlusion (RVO) often feels like. It’s not rare. Around 16.4 million people worldwide live with it. And for many, it’s not just a one-time event - it’s the start of a long road of treatments, injections, and constant monitoring.

What Exactly Is Retinal Vein Occlusion?

Your retina is the light-sensitive layer at the back of your eye. It turns images into signals your brain understands. Blood flows into the retina through arteries and leaves through veins. When one of those veins gets blocked - usually because of a clot or pressure from a hardened artery - blood backs up. Fluid leaks into the retina, swelling the macula (the part you use for sharp central vision). That’s RVO.

There are two main types:

• Central Retinal Vein Occlusion (CRVO): The main vein is blocked. Vision loss tends to be more severe.
• Branch Retinal Vein Occlusion (BRVO): Only a smaller branch is blocked. Vision loss is often partial - maybe just the top or bottom half of your vision.

Both types cause painless vision changes. The damage isn’t from the blockage itself - it’s from the swelling (macular edema) and lack of oxygen that follow.

Who’s Most at Risk?

RVO doesn’t pick favorites, but it does favor certain people. Over 90% of CRVO cases happen in people over 55. Half of all cases occur in those 65 and older. But it’s not just an older person’s disease - 5 to 10% of cases strike people under 45.

Here’s what increases your risk the most:

• High blood pressure: Present in up to 73% of CRVO patients over 50. It’s the #1 risk factor. Uncontrolled hypertension makes blood vessels stiff and prone to clotting.
• High cholesterol: About 35% of RVO patients have total cholesterol above 6.5 mmol/L. Fatty deposits narrow blood vessels, making blockages more likely.
• Diabetes: Affects about 10% of RVO patients over 50. It damages blood vessel walls over time, making them leaky and fragile.
• Glaucoma: High pressure inside the eye can physically compress the retinal vein, especially where it passes through the optic nerve.
• Smoking: Found in 25-30% of cases. It thickens blood, damages vessel linings, and speeds up artery hardening.
• Obesity and inactivity: Both raise inflammation and blood pressure, indirectly raising RVO risk.

For younger women under 45, oral contraceptives are a common link - especially with CRVO. Blood clotting disorders like factor V Leiden or protein S deficiency also show up more often in this group.

How Do Doctors Diagnose It?

It starts with a simple eye exam. Your doctor will check your vision and look at the back of your eye with a special lens. But the real clues come from advanced imaging:

• Optical Coherence Tomography (OCT): This scan shows the thickness of your retina. If the macula is swollen (macular edema), it shows up clearly - usually when central subfield thickness exceeds 300 micrometers.
• Fluorescein angiography: A dye is injected into your arm, and a camera tracks how it flows through the retinal vessels. It shows exactly where the blockage is and if new, leaky blood vessels are forming.

These tests don’t just confirm RVO - they guide treatment. Without them, you’re flying blind.

The Role of Injections: Anti-VEGF and Steroids

There’s no magic cure to unblock the vein. Treatment focuses on stopping the damage - mainly the swelling and abnormal blood vessel growth.

The go-to treatment? Anti-VEGF injections. VEGF is a protein that causes leaky blood vessels and swelling. Blocking it reduces fluid buildup and can restore vision.

Three drugs are used:

• Ranibizumab (Lucentis): Approved for RVO in 2010. Clinical trials showed patients gained an average of 16.6 letters of vision in a year.
• Aflibercept (Eylea): Approved in 2012. In trials, patients gained 18.3 letters on average. Studies now show it works better than others when baseline vision is worse than 20/50.
• Bevacizumab (Avastin): Originally a cancer drug, it’s used off-label because it’s cheap - about $50 per shot vs. $2,000 for the others. It works just as well for many patients.

Injections are given directly into the eye. The procedure takes 5-7 minutes. You get numbing drops, your eye is cleaned with antiseptic, and a tiny needle delivers the drug. Most people feel only slight pressure.

Side effects are rare but include:

• Red spot on the white of the eye (subconjunctival hemorrhage) - happens in 25-30% of cases
• Temporary increase in eye pressure - 15-20% of patients
• Floaters - 10% of cases
• Endophthalmitis (serious eye infection) - less than 0.1% of injections

What About Steroid Injections?

If anti-VEGF doesn’t work well enough, doctors turn to steroids. The dexamethasone implant (Ozurdex) is a tiny, dissolvable pellet injected into the eye. It slowly releases steroid over 3-6 months.

In the GENEVA trial, 27.7% of CRVO patients gained 15 or more letters of vision with Ozurdex - compared to 12.9% with placebo. That’s a big jump.

But steroids come with trade-offs:

• Up to 70% of patients develop cataracts faster
• 30% get elevated eye pressure, sometimes needing medication or surgery

Because of this, most doctors try anti-VEGF first. Steroids are usually reserved for those who don’t respond to anti-VEGF or can’t handle monthly shots.

How Often Do You Need Injections?

It’s not a one-and-done fix. Most patients need monthly shots for 3-6 months until swelling clears. Then, doctors switch to “as needed” dosing - checking with OCT every 4-8 weeks.

Real-world data shows patients get 8-12 injections per year on average. The goal? Keep central subfield thickness below 250 micrometers.

Newer protocols like treat-and-extend are changing the game. Instead of fixed monthly shots, doctors gradually stretch the time between injections if the eye stays stable. One 2023 study found this approach cut injection frequency by 30% without losing vision gains.

What’s the Real-World Experience Like?

Patients don’t just see numbers on a chart. They feel the cost, the fear, the fatigue.

One man, 62, started monthly Lucentis shots after CRVO. His vision improved from 20/200 to 20/60 - life-changing. But each injection cost $150 out-of-pocket. On a fixed income, that added up fast.

Another patient tried eight Avastin shots with little improvement. Then she got the Ozurdex implant. Ten lines of vision gained. Worth the $2,500 price tag, she says.

But the emotional toll is real. People talk about anxiety before each shot. Some develop “injection fatigue” - missing appointments because the stress becomes too much. One patient stopped going after 18 months, even though her vision kept improving.

A 2022 survey of over 1,200 RVO patients found:

• 78% saw significant vision improvement after a year of anti-VEGF therapy
• 63% struggled with financial burden
• 41% felt overwhelmed by treatment frequency

What’s Next for RVO Treatment?

The future is about reducing burden. Researchers are testing:

• Extended-delivery systems: Like Susvimo - a tiny pump implanted in the eye that releases ranibizumab for months at a time. It’s approved for AMD and in trials for RVO.
• Gene therapy: RGX-314 delivers a gene that makes your eye produce its own anti-VEGF protein. Early trials show promise for long-term suppression without injections.
• New drugs: OPT-302 blocks a different VEGF protein (VEGF-C/D) and is being tested alongside aflibercept for stubborn cases.

Doctors are also using optical coherence tomography angiography (OCTA) to spot early signs of poor blood flow before swelling even starts. This could lead to earlier, smarter treatment.

Can You Prevent RVO?

You can’t undo aging, but you can control your risks:

• Keep blood pressure under 130/80
• Manage cholesterol with diet, exercise, and meds if needed
• Control blood sugar if you have diabetes
• Quit smoking - it’s the single biggest lifestyle change you can make
• Exercise regularly - even a 30-minute walk daily helps circulation
• Get annual eye exams - especially if you’re over 50 or have risk factors

RVO often happens because other health problems go unnoticed. A routine eye exam can catch early signs of high blood pressure or diabetes before they cause permanent damage.

Final Thoughts

Retinal vein occlusion isn’t just an eye problem - it’s a warning sign. It’s your body telling you something’s wrong with your blood vessels. And while injections can restore vision, they’re not a cure. The real win is preventing it in the first place.

If you’ve been diagnosed, stick with your treatment. Don’t skip appointments. Ask about cost-saving options like bevacizumab. Talk to your doctor about treat-and-extend plans. And remember - vision improvement is possible. Many people go from barely seeing to reading again. It takes time, patience, and persistence.