Has your vision suddenly become blurry? This could be due to a blocked vein in your eye (Retinal Vein Occlusion - RVO).

Have you suddenly noticed that your vision in one eye is a little blurry? Or do you feel like small black objects are floating in front of your eye? It's normal to feel a little scared when something like this happens. Most of the time, this can be caused by a blockage in a tiny blood vessel inside your eye. In medical terms, we call this Retinal Vein Occlusion, or RVO for short. Let's talk about this in simple terms today.

Simply put, what is retinal vein occlusion (RVO)?

Think of your eye as a camera. The retina is like the film on the back of the camera. This is where the light from the things we see is converted into images. So, to work properly, the retina needs a good blood supply. That means there are arteries that bring blood to the eye and veins that carry used blood back.

Now imagine that for some reason, a vein that carries that blood back, a vein, becomes slightly blocked or obstructed. Just like when a water pipe gets blocked, the blood can't flow through it. Then, the blood backs up, increasing the pressure inside the retina and causing it to swell. This is what we call Retinal Vein Occlusion (RVO) . This is a condition that needs to be treated quickly, or it can cause permanent vision loss.

There are two main types of RVOs.

We divide RVO into two types depending on where this blockage occurs.

What symptoms might you experience during an RVO situation?

Symptoms of RVO usually affect only one eye. They can start suddenly or develop gradually over a period of hours or days.

• Blurred vision or loss of vision: This is the main and most common symptom.
• Floaters: Seeing black dots or lines floating in front of the eyes.
• Feeling of pain or pressure inside the eye: This is seen in more severe cases.

Why does a vein get stuck inside the eye like this?

It's really hard to pinpoint a single reason for this, but there are several main factors at play.

Simply put, there are places where an artery and a vein in the retina cross each other. As we age, or because things like cholesterol build up, the artery walls become a little thicker and harder. We call this atherosclerosis . A thickened artery like this starts to press on the delicate vein underneath it. It's like a water pipe being crushed when something heavy is placed on top of it. This pressure can obstruct the flow of blood inside the vein, and a blood clot can form and completely block the vein.

In addition, certain medical conditions also increase the risk of developing RVO.

Factors that increase the risk of RVO

What complications can occur if left untreated?

If RVO is not treated promptly, it can cause serious damage to the eye.

• Cystoid Macular Edema: The macula is the most important central part of the retina that gives us clear, sharp vision. When a blood vessel becomes blocked, it can fill with fluid and swell. This can cause severe blurring of vision.
• Neovascularization: When blood flow inside the eye is impaired , the body tries to make up for the deficiency by forming new blood vessels. However, these new vessels are very weak and have thin walls. These can easily burst and cause bleeding inside the eye (vitreous hemorrhage).
• Increased pressure in the eye (Neovascular Glaucoma): These new, weak blood vessels block the areas that control the flow of fluid inside the eye. This can cause dangerously high pressure inside the eye, damaging the optic nerve and causing complete loss of vision.
• Retinal Detachment: This is an emergency. The retina can detach from the wall of the eye due to the pulling of the new blood vessels.

How does a doctor diagnose and treat this?

If you experience these symptoms, you should see an eye care specialist as soon as possible. He or she will examine your eyes carefully.

Diagnosis

The doctor will put drops in your eye to dilate the pupil and examine the inside of your eye with a special microscope. In addition, the following tests may be performed:

• Optical Coherence Tomography (OCT) scan: This can measure the thickness of the retina and accurately determine whether the macula is swollen.
• Fluorescein Angiography: A special dye is injected into a vein in your arm and pictures are taken as it travels through the blood vessels inside your eye. This can show where the vein is blocked and how much damage has occurred.

Treatment methods

To date, there is no safe way to reopen a blocked vein. However, there are many effective treatments to control the damage and complications caused by the blockage . The main goals of these treatments are:

• Improve your vision or stop it from getting worse.
• Treatment of complications that have arisen.
• Controlling risk factors (such as blood pressure and diabetes) that contribute to RVO.

Here are some of the main treatment methods:

1. Anti-VEGF Injections: This is the most commonly used first-line treatment. There is a chemical (VEGF) that causes swelling and the formation of new, weak blood vessels inside the eye. This injection works by blocking that chemical. The injection is given after the eye is numbed with eye drops. Depending on your condition, you may need to get these injections monthly or at regular intervals.

2. Steroid Injections: These injections are also used to reduce swelling. However, they can increase eye pressure in some people, so they are only given as a second option if anti-VEGF injections do not help.

3. Laser treatment (Panretinal Photocoagulation - PRP): This laser treatment is used to stop the formation of unwanted, weak blood vessels.

4. Vitrectomy Surgery: If there is a lot of bleeding inside the eye, this surgery is performed to remove and clean the blood-filled jelly-like part of the eye.

About the future and what we can do

How your vision will look after RVO depends on several factors. Some people have permanent vision loss, while others see their vision gradually improve over time with treatment. Your eye doctor can best explain your situation.

The best thing we can do to prevent this situation is to control risk factors.

• Follow a diet that is good for the heart and blood vessels.
• Exercise daily.
• Maintain a healthy weight.
• Avoid smoking completely.

If you have this condition, you may feel tired and stressed out because you have to take frequent injections and go to clinics. Don't be embarrassed about it. Talk to your doctor about it. He or she will give you the support you need.

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