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Retinal Vascular Occlusion

What Is Retinal Vascular Occlusion?

Retinal vascular occlusion is a condition that occurs when one of the blood vessels carrying blood to or from the retina becomes blocked. This interruption in blood flow can lead to sudden vision loss and may result in permanent damage if not treated promptly.

There are two main types:

  • Central Retinal Artery Occlusion (CRAO): A blockage in the main artery supplying the retina

  • Central Retinal Vein Occlusion (CRVO): A blockage in the main vein draining blood from the retina

There are also branch occlusions, affecting smaller vessels:

  • Branch Retinal Artery Occlusion (BRAO)

  • Branch Retinal Vein Occlusion (BRVO)

These are considered ocular emergencies, particularly CRAO, which is sometimes likened to a “stroke in the eye.”


Causes of Retinal Blood Vessel Blockage

The causes can vary depending on whether the artery or vein is affected, but most cases are related to underlying systemic vascular diseases.

Common Causes Include:

  • Atherosclerosis (hardening of arteries)

  • Hypertension (high blood pressure)

  • Diabetes mellitus

  • High cholesterol levels

  • Blood clotting disorders

  • Heart disease and arrhythmias

  • Inflammatory vascular conditions

  • Smoking and sedentary lifestyle

  • Glaucoma (increases the risk of vein occlusion)

In rare cases, an embolism from the heart or carotid artery can travel and lodge in the retinal vessels.


Symptoms to Watch For

Symptoms can vary depending on the type and severity of occlusion:

Arterial Occlusion (CRAO/BRAO)

  • Sudden, painless, severe vision loss in one eye

  • Vision may be reduced to light perception only

  • Occasionally preceded by transient vision loss (amaurosis fugax)

Venous Occlusion (CRVO/BRVO)

  • Blurry or distorted vision

  • Gradual or sudden vision changes

  • Dark spots or floaters

  • In some cases, eye pain due to increased eye pressure

These symptoms are ocular emergencies and require urgent care to minimize permanent vision loss.


Diagnosis at Bangkok Eye Hospital

At Bangkok Eye Hospital, timely diagnosis and assessment are critical. Diagnostic procedures include:

  • Dilated fundus examination to visualize blood flow and retinal health

  • Optical Coherence Tomography (OCT) to detect retinal swelling or fluid accumulation

  • Fluorescein angiography to assess blood circulation in the retina

  • Ultrasound (B-scan) if there is significant hemorrhage

  • Blood tests and cardiovascular screening to investigate underlying systemic conditions

  • Carotid artery ultrasound and echocardiography, if embolism is suspected

Early intervention improves outcomes, particularly in CRAO cases where treatment within hours is most effective.


Treatment Options for Retinal Vascular Occlusion

There is no single cure, but various treatment options aim to restore circulation, reduce swelling, and prevent further vision loss.

For Artery Occlusion (CRAO/BRAO)

  • Immediate ocular massage and breathing into a paper bag to increase CO₂ and dilate vessels

  • Reducing intraocular pressure using medication or anterior chamber paracentesis

  • Hyperbaric oxygen therapy in select cases

  • Management of cardiovascular risk factors and antiplatelet therapy

Unfortunately, recovery is limited if treatment is delayed beyond a few hours.

For Vein Occlusion (CRVO/BRVO)

  • Intravitreal injections of anti-VEGF drugs (e.g., ranibizumab, aflibercept) to reduce macular edema

  • Intravitreal steroids for inflammation and swelling

  • Laser photocoagulation to treat neovascularization or ischemic areas

  • Ongoing monitoring to prevent complications such as neovascular glaucoma

Treatment is usually ongoing and requires regular follow-ups.


Complications of Retinal Vascular Occlusion

If untreated, vascular occlusion can lead to:

  • Permanent vision loss

  • Macular edema

  • Neovascularization (abnormal vessel growth)

  • Glaucoma (due to increased pressure)

  • Retinal hemorrhage or detachment

Managing systemic conditions such as hypertension and diabetes is crucial to prevent recurrence.


Prevention and Risk Management

  • Maintain healthy blood pressure and cholesterol levels

  • Manage blood sugar in diabetic patients

  • Stop smoking

  • Exercise regularly and follow a balanced diet

  • Attend regular eye exams, especially if you have cardiovascular risk factors

  • Take prescribed blood thinners or antiplatelet drugs under medical supervision

Early detection of changes in the eye’s blood vessels can reduce the risk of future blockages.


Related Services at Bangkok Eye Hospital

Bangkok Eye Hospital offers a range of specialized services for vascular-related eye conditions:

  • Retinal Disease and Macula Clinic
    For diagnosis and long-term management of occlusions, edema, and ischemia

  • Fluorescein Angiography and OCT Center
    For high-resolution imaging of retinal blood flow and structure

  • Intravitreal Injection Unit
    For anti-VEGF and steroid therapy

  • Cardiovascular and Diabetes Eye Screening
    Early detection for at-risk individuals

  • Emergency Eye Care Unit
    For sudden vision loss or acute vascular episodes


Frequently Asked Questions (FAQs)

Is retinal vascular occlusion the same as a stroke?
Yes, in many ways. CRAO is often referred to as an "eye stroke" and is an emergency requiring immediate medical attention.

Can vision be restored after an occlusion?
Partial recovery is possible, especially in vein occlusions. Arterial occlusions have a narrow treatment window for recovery.

What’s the difference between CRAO and CRVO?
CRAO involves an artery supplying blood to the retina, while CRVO involves a vein draining blood away. Symptoms and treatment differ.

Who is most at risk for retinal vascular occlusion?
People over age 50 with high blood pressure, diabetes, high cholesterol, or heart disease are at higher risk.

How can I prevent future occlusions?
By managing systemic health conditions, quitting smoking, and having regular eye exams to monitor eye and vascular health.

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