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.”
The causes can vary depending on whether the artery or vein is affected, but most cases are related to underlying systemic vascular diseases.
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 can vary depending on the type and severity of occlusion:
Sudden, painless, severe vision loss in one eye
Vision may be reduced to light perception only
Occasionally preceded by transient vision loss (amaurosis fugax)
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.
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.
There is no single cure, but various treatment options aim to restore circulation, reduce swelling, and prevent further vision loss.
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.
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.
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.
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.
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
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.