Vein and Artery Occlusions

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Vein and Artery Occlusions

The retina plays a vital role in our vision by capturing light and converting it into signals that our brain can interpret. To work properly, it relies on a steady supply of oxygen-rich blood delivered through the retinal artery and drained through the retinal vein and their branching vessels. When one of these vessels becomes blocked, blood flow is disrupted, depriving the retina of the oxygen and nutrients it needs. Without prompt treatment, this can lead to significant or even permanent vision loss.

Retinal Vein Occlusions

A retinal vein occlusion occurs when a retinal vein becomes blocked, usually due to a blood clot or a large blood vessel pressing on it. There are two types of retinal vein occlusions: central retinal vein occlusion (CRVO) and branch retinal vein occlusion (BRVO).

Central retinal vein occlusion (CRVO)

CRVO occurs when there is a blockage in the central retinal vein. This blockage can damage the vein's structure, lead to blood and fluid leakage into the retina, and cause blurred central vision.

In response to this blockage, new abnormal blood vessels grow, which are prone to bleeding and leaking. This can lead to the appearance of dark streaks or spots (floaters) in the visual field. CRVO is often associated with conditions such as high blood pressure, diabetes, glaucoma, and various blood disorders.

Branch retinal vein occlusion (BRVO)

BRVO occurs due to blockages in the smaller blood vessels that branch off from the central retinal vein. If the affected veins are close to the macula, the center of the retina, they can cause it to swell, a condition known as macular edema. Additionally, BRVO can cause blurred central vision and promote the growth of new abnormal blood vessels that may leak fluid into the eye.

Retinal Artery Occlusions

A retinal artery occlusion occurs when a blood clot or a buildup of cholesterol blocks blood flow in one or more retinal arteries. There are two types of retinal artery occlusions: branch retinal artery occlusion (BRAO) and central retinal artery occlusion (CRAO).

Central retinal artery occlusion (CRAO)

Also called an "eye stroke," CRAO occurs when a blood clot forms in the central retinal artery. It can be an indicator of serious cardiovascular disease and increases the risk of a brain stroke.

Branch retinal artery occlusion (BRAO)

Similar to a central retinal artery occlusion, BRAO can cause irreversible vision loss. If diagnosed, your retinal specialist will guide you on the appropriate work up, including any testing that may be required.

Common Risk Factors for Vein and Artery Occlusions

Blood clots can cause blockages that may lead to vein and artery occlusions. Common risk factors include:

• Age
• High blood pressure
• Diabetes
• Smoking
• Blood clotting disorders
• Obesity
• Pregnancy

Vein and Artery Occlusion Symptoms

Vein and artery occlusions are painless and typically occur in one eye. They may come on suddenly or worsen over time. Common symptoms include blurred or dimming vision. If you experience sudden vision loss, seek medical assistance immediately.

Diagnosing Vein and Artery Occlusions

Retina specialists can diagnose vein and artery occlusions through a comprehensive eye exam. Further diagnostic tests often include:

• Eye dilation: During an eye exam, your doctor will use special drops to widen your pupil, allowing for a better examination of the retina.
• Ophthalmoscopy: A retina specialist may use an ophthalmoscope to shine a light into the eye and examine the retina.
• Fluorescein angiography: In this test, a retina specialist injects colored dye into the bloodstream. This dye travels to the blood vessels in the eye, and a special camera captures images to identify any abnormalities in the retina.
• Indocyanine green angiography: Like fluorescein angiography, this test also involves an intravenous injection of dye. However, the type of dye used in this test absorbs infrared light, making it easier to visualize deeper blood vessels in the retina.
• Optical coherence tomography (OCT): This non-invasive technique uses infrared light waves to capture detailed images of the retina.

Treating Vein and Artery Occlusions

Treatments for vein and artery occlusions can range from managing underlying conditions like diabetes to surgical options like laser photocoagulation. During laser photocoagulation, a retina specialist uses a focused beam of light to create small burns on the retina. This procedure can seal leaking blood vessels, repair tears, and reduce the growth of abnormal blood vessels.

Your doctor may also recommend anti-vascular endothelial growth factor (anti-VEGF) medications. A retina specialist administers these medications by injecting them directly into the eye with a thin needle. Anti-VEGF medications work by blocking the protein that promotes the growth of abnormal blood vessels, thereby helping halt their progression.

Long-Term Outlook of Vein and Artery Occlusions

Prognosis depends on many factors, including the location of the blockage and potential complications. For some individuals, vision gradually gets better over time, whereas others may experience permanent vision damage. It's important to see a retina specialist regularly to monitor the condition and develop a treatment plan tailored to your specific needs.