Retinal vein occlusions are blockages in the blood vessels carrying blood away from your retina, which is the light-sensitive layer at the back of the eye.

Like its sibling (retinal artery occlusion, which affects the vessels carrying blood towards the retina instead of away from it), retinal vein occlusion is considered a serious condition. It can even lead to complications like glaucoma and macular oedema.

It can also lead to vision loss. In fact, retinal vein occlusions remain the second most common cause of blindness due to problems with the blood vessels of the retina (after diabetic retinopathy).

This makes it vital to diagnose retinal vein occlusion as soon as possible, as early detection is one of the few ways to make management or prevention of its complications a possibility.

Types of Retinal Vein Occlusions

Generally, retinal vein occlusions are categorised based on where the blockage happens. Here are the two main types of vein occlusions:

• Branch Retinal Vein Occlusion (BRVO) – The most common form of retinal vein occlusion, BRVO is what happens when the blockage occurs in a branch vein of the retina.

• Central Retinal Vein Occlusion (CRVO) – This is a more serious form of retinal vein occlusion where the main or central vein of the retina is blocked.

The Causes of Retinal Vein Occlusions

So, what causes branch retinal vein occlusion? There are several possible causes for it as well as the type that affects the central veins. They include the following:

• A blood clot
• Slowed blood flow, which can cause platelets to clump together and form a clot
• Retinal vein compression

The last cause is often due to atherosclerosis or hardening of the arteries. Hardened retinal arteries can get so stiff that they begin to exert pressure on the vein nearby. Over time, this pressure can damage the retinal vein, which makes blood clots more likely to form.

The Risk Factors for Retinal Vein Occlusions

Any condition that increases the likelihood of blood clots, vascular damage (blood vessel damage), and increased pressure on the retinal vein is considered a risk factor for retinal vein occlusion.

For instance, these are commonly cited as risk factors for the condition:

• Atherosclerosis
• Blood clotting disorders like Factor V Leiden
• Diabetes
• Glaucoma
• High cholesterol levels
• High blood pressure
• Infection (since it raises the chances of blood clots forming)
• Obesity (often due to it being a risk factor for a lot of the other conditions in this list)

Recognising the Symptoms of Retinal Vein Occlusion

Retinal vein occlusion signs can be acute or gradual. Unfortunately, they are also typically painless, which may lead to a lot of people ignoring them at first.

In most cases, both central and branch retinal vein occlusion symptoms will affect only one eye. This happens for the same reason it does in retinal artery occlusions: because it is highly unlikely for a person to suffer vascular occlusions to both eyes at exactly the same time.

In any case, these are the symptoms associated with retinal vein occlusions:

• Blurry vision or vision loss that may develop over as little time as a few hours or as much time as several days. Either way, the vision loss is typically unexplained.
• Floaters, or dark spots and occasionally lines that “float” over your field of vision.
• Pain or pressure in the eye. As noted earlier, most retinal vein occlusion is actually painless, so this is less likely to present. If it does appear, it may be an indication that the case is a serious one.

The difficulty with retinal vein occlusions is one they have in common with many other eye problems: they may only begin to show noticeable symptoms when the condition has already progressed far enough for complications.

This means that there are many cases where retinal vein occlusions get diagnosed too late to preserve much of a person’s vision. Vision loss from these occlusions and their complications can be permanent, which makes quick action vital.

Book an appointment with an eye doctor to get screened for RVO now

On the whole, retinal vein occlusion is fairly similar to retinal artery occlusion, which we discussed in a previous article. Just like the other condition, it also requires prompt attention if one is to reduce the odds of complications forming.

If you suspect you may have RVO – or just want to ensure that your eyes are free of issues – you can let our eye doctors assess you. We can also run exams to check if other conditions are present, and come up with suitable treatment plans even if something is discovered.

Call us to enquire or book an appointment for an eye screening now.

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