The retina is a thin layer of tissue that lines the back of your eye. It has special cells called photoreceptors. They turn light into signals, which the brain interprets as the images that you see.
What Is Retinal Vein Occlusion?
Arteries supply the retina with blood, and veins carry blood away. Sometimes, a vein becomes partially or completely blocked. This is called retinal vein occlusion, or RVO. The condition affects fewer than 1% of adults around the world. Retinal vein occlusions are similar to retinal artery occlusion (RAO), sometimes called an eye stroke, but are more common. In fact, it’s the second most common condition that affects the retina.
When blood backs up and can’t drain from the retina, your eye can be damaged in minutes:
- Leaking fluid can cause the macula, the part of the retina in the back of your eye, to swell or thicken and can lead to permanent damage and vision loss.
- New, abnormal blood vessels can grow in your iris (the colored part of your eye) because of the blockage. This raises pressure inside your eye, which might lead to a type of glaucoma called neovascular glaucoma.
- Bleeding in the back of your eye can cause retinal detachment.
There are two types of retinal vein occlusion: branch retinal vein occlusion (BRVO) and central retinal vein occlusion (CRVO). The type you have depends on where the blockage is.
Central Retinal Vein Occlusion
Retinas have one main vein and several veins that branch off from it. Central retinal vein occlusion, or CRVO, occurs when the main, or central, vein becomes blocked.
Central retinal vein occlusion can happen quickly, triggering sudden vision loss. Or it can happen over several hours or days. The first sign of CRVO might be floaters. These are tiny spots that seem to float in your vision. They can also look like tiny lines or squiggles.
If your CRVO is severe, you might feel pain from the pressure.
Branch Retinal Vein Occlusion
If one of the smaller veins that branch off the main vein in your retina gets blocked, it’s called branch retinal vein occlusion, or BRVO.
Like CRVO, branch retinal vein occlusion can happen suddenly or over hours or days. And it can cause sudden loss of sight. You also might see floaters before that happens, but the most common symptoms is blurry vision or vision loss in just part of your eye.
Retinal Vein Occlusion Causes
Retinal vein occlusion is usually caused by a blood clot blocking the vein. But a nearby artery can sometimes be the problem. Arteries and veins cross over each other in the retina. If an artery wall hardens (which is called atherosclerosis), it may press against a vein, causing it to narrow. This causes choppy blood flow, which may lead to clotting.
Some people have risk factors that make them more likely to get a retinal vein occlusion. But some people get it who don't have any risk factors. When people without risk factors get it, it's called idiopathic retinal vein occlusion. "Idiopathic" means the reason is unknown.
Retinal Vein Occlusion Risk Factors
Your risk for retinal vein occlusion goes up if you have diabetes, high blood pressure, or other conditions that affect the blood vessels.
Other risk factors include:
- Smoking
- Being overweight
- Older age
- Lymphoma
- Leukemia
- Multiple myeloma
- Trauma to the eye
- Glaucoma
- High blood pressure
Retinal vein occlusion is unusual in younger people. If it happens, it could be caused by blood that clots too easily.
Retinal Vein Occlusion Symptoms
Some people, especially those with a blockage in a smaller blood vessel, have no symptoms. Some people only find out they have a retinal vein occlusion during a routine eye exam.
If you have a retinal vein occlusion, you might notice:
Call your doctor right away if you have any of these symptoms.
Retinal Vein Occlusion Diagnosis
Your doctor needs to check your retina to see if there is any damage. To do that, they put drops in your eyes to dilate, or widen, your pupils. Using a tool called an ophthalmoscope, they look through your pupil to your retina for signs of blockage or bleeding.
Your doctor may also do:
Fluorescein angiography. This helps your doctor see the blood vessels in your retina more clearly. Dye is injected into a vein in your arm so it can travel through your bloodstream to your retina. Once there, the dye makes the blood vessels stand out and a special camera takes pictures.
Optical coherence tomography (OCT). This also helps your doctor see the retina more clearly. You may get drops to dilate your pupils. You’ll sit in front of an OCT machine and look directly through a small window. The machine then scans your eyes for 5 to 10 minutes.
Optical coherence tomography angiography (OCTA). This test is similar to the OCT but gives more detailed images.
Fundus photography. This imaging test allows your doctor to see if any abnormal blood vessels have formed and how much blood may be inside your eye. They may give you eye drops to dilate your pupils. A machine takes photos of the inner part of your eye.
If you have a retinal vein occlusion, it’s important to find out if you have a risk factor that ups your chances of forming one again. Your eye doctor may want you to work with your primary care doctor to test for diabetes or high blood pressure.
Retinal Vein Occlusion Treatment
There’s no cure for retinal vein occlusion. Your doctor can’t just unblock the retinal veins. Instead, treatment focuses on any complications and protecting your vision. In some cases, doctors choose not to treat, but will monitor carefully and only treat if they see any more damage.
Your vision may stay the same, improve, or get worse with or without treatment. It all depends on your unique situation. Treatment can include:
Anti-VEGF injections
Injectable anti-vascular endothelial growth factor (anti-VEGF) drugs are the first choice for treating retinal vein occlusion. They target a protein that causes new, abnormal blood vessels to grow. The injections also help ease swelling. You may need repeat injections over a year or two for them to be effective. Your doctor will numb your eye first with anesthetic drops.
Anti-VEGF drugs include:
- Aflibercept (Eylea)
- Bevacizumab (Avastin)
- Ranibizumab (Byooviz, Cimerli, Lucentis, Susvimo)
Bispecific antibodies
A newer type of injectable drug, called a bispecific antibody, targets VEGF along with another protein that promotes fluid buildup and swelling. The FDA has approved faricimab-svoa (Vabysmo) to treat retinal vein occlusion.
Steroid shots
Your doctor can also give you steroid shots in your eye to ease swelling, but this is considered a second-line therapy. In other words, it probably won’t be your doctor’s first choice. They might consider it if the first treatment didn’t help. Not everyone can get steroid injections because they can lead to higher eye pressure and glaucoma. Just like the other injections, you’ll get pain-numbing eye drops first.
Focal laser therapy
If your retinal vein occlusion is hard to treat, your doctor may do focal laser photocoagulation alongside the injections. The laser burns and seals off blood vessels near the macula. This keeps them from leaking. The retina does not have pain nerves, so you should not feel much discomfort.
Laser surgery
Laser surgery for retinal vein occlusion is called panretinal photocoagulation, or PRP. You may need this to avoid more vision loss if you grow new abnormal blood vessels in your eye. Your doctor will use a laser to make tiny burns on the retina. This stops the vessels from leaking and growing. The procedure usually takes several sessions, and each session is about 15-30 minutes.
Vitrectomy surgery
Your doctor might recommend this procedure if you have complications from a retinal vein occlusion like:
- Severe bleeding in the eye
- Bleeding that lasts for more than a month or comes back
- A detached retina
For this surgery, the doctor would remove the gel-like substance that’s in the middle of your eye called vitreous humor.
Your eye will be numbed and you may be given general anesthesia to help you sleep through the procedure. The doctor uses very fine tools to remove the vitreous humor and then replaces it with one of the following:
- Sterile salt water
- A gas bubble
- Silicone oil
You might have to lie face down for a while after the surgery. Your doctor will let you know how long. You may have to wear an eye patch for a while, too.
Retinal Vein Occlusion Prevention
If you have any risk factors, you can lower your risk of retinal vein occlusion by managing them:
- Keep your blood pressure, cholesterol, and blood sugar under control.
- If you have diabetes, get your eyes checked every year.
- If you smoke, try to stop.
- Prevent eye injuries by using protective eye gear when needed.
- If you take birth control pills, talk to your doctor. Rarely, they can lead to retinal vein occlusion.
Retinal Vein Occlusion Takeaways
Retinal vein occlusion can cause partial or total blindness in the eye. It happens when blood can’t flow freely in your retina. It can happen quickly or over a few hours or days. Doctors can’t reverse the damage, but there are treatments that can keep it from getting worse. Get your eyes checked regularly, especially if you have any risk factors that can raise your chances of retinal vein occlusion.
