Branch Retinal Vein Occlusion
A blocked vein in part of the retina that affects vision
Quick Facts
- Type: Retinal blood vessel disorder
- Core problem: Blockage of a branch retinal vein
- Main symptom: Painless blurring or loss of part of vision
- Linked to: High blood pressure, diabetes, glaucoma
Overview
The retina is the light-sensing layer at the back of the eye. Blood drains away from the retina through veins that join into one main vein. Branch retinal vein occlusion (BRVO) occurs when one of the smaller (branch) retinal veins becomes blocked, usually where an artery crosses and presses on it. With the drainage blocked, blood and fluid back up into the part of the retina served by that vein.
This causes bleeding (hemorrhage) and swelling in the affected area, which can blur or reduce vision in that part of the eye. Because only one section of the retina is involved, the vision change is often partial rather than affecting the whole field. BRVO is one of the more common retinal vascular disorders and is strongly linked to conditions that affect blood vessels, such as high blood pressure.
Symptoms
BRVO usually affects one eye and is typically painless. Symptoms can include:
- Sudden or gradual blurring of part of the vision
- A blind spot or shadow in one area of the visual field
- Distorted vision
- Loss of central vision if the macula is affected
Some people notice little change if the blocked area is small or away from the center of vision. Because a sudden change in vision can have several causes, including more urgent ones, any new vision loss should be evaluated promptly by an eye specialist.
Causes
BRVO results from a blockage in a branch retinal vein, usually where a stiffened artery crosses over and compresses it. Contributing factors include:
- High blood pressure: A major risk factor that stiffens and narrows arteries.
- Atherosclerosis: Hardening of the arteries that increases pressure at crossing points.
- Diabetes: Damages small blood vessels throughout the body.
- Glaucoma: Raised eye pressure is associated with vein occlusions.
- Blood and clotting disorders: Conditions that thicken the blood or promote clotting.
Risk Factors
- High blood pressure
- Older age
- Diabetes
- High cholesterol and atherosclerosis
- Glaucoma or raised eye pressure
- Smoking
- Blood clotting disorders
Diagnosis
An eye specialist diagnoses BRVO with an eye exam and imaging:
- Dilated eye exam: Reveals bleeding, swelling, and the pattern of a blocked branch vein in the retina.
- Optical coherence tomography (OCT): Measures swelling of the macula and retina.
- Fluorescein angiography: A dye study that shows blood flow and areas of leakage or poor circulation.
- General assessment: Blood pressure, blood sugar, and other tests to find underlying conditions.
Treatment
Treatment focuses on the complications that threaten vision, mainly swelling of the macula and abnormal new blood vessels. An eye specialist guides care.
- Anti-VEGF injections: Medicines injected into the eye reduce macular swelling and leakage and can improve vision.
- Corticosteroid treatment: Steroid injections or implants in the eye may reduce swelling in some cases.
- Laser treatment: Used to treat persistent swelling or to address abnormal new vessels that can develop.
- Managing risk factors: Controlling blood pressure, blood sugar, and cholesterol helps protect both eyes.
Many people recover useful vision, especially with early treatment, though some loss can remain depending on how much the macula was affected.
Prevention
- Keep blood pressure well controlled
- Manage diabetes and cholesterol
- Do not smoke
- Have regular eye exams, especially if you have glaucoma or vascular risk factors
- Report any sudden vision change promptly
- Follow your eye specialist's monitoring plan if you have had a vein occlusion
When to See a Doctor
See an eye specialist promptly for any sudden or unexplained change in vision, including:
- New blurring or a blind spot in part of your vision
- Distorted or reduced central vision
- A shadow over one area of sight
Sudden, painless vision loss can have several causes, some urgent, so it should always be evaluated quickly. Seek emergency care for sudden complete vision loss, especially with severe eye pain or a curtain coming over your sight.
Frequently Asked Questions
What is branch retinal vein occlusion?
It is a blockage of one of the smaller veins that drain blood from the retina, usually where an artery presses on it. The blockage causes bleeding and swelling in part of the retina, which can blur or reduce vision in that area of the eye.
What causes a branch retinal vein to block?
It usually happens where a stiffened artery crosses and compresses the vein. High blood pressure, hardening of the arteries, diabetes, high cholesterol, and glaucoma all increase the risk.
What are the symptoms?
Most people notice painless blurring or a blind spot in part of the vision of one eye. If the central retina (macula) is involved, central vision can be reduced. Some small occlusions cause little noticeable change.
How is it treated?
Treatment targets the swelling and any abnormal new vessels, mainly with anti-VEGF injections into the eye, sometimes steroids or laser treatment. Controlling blood pressure, blood sugar, and cholesterol helps protect vision over the long term.
Will my vision recover?
Many people regain useful vision, especially with early treatment of macular swelling. The amount of recovery depends on how much the macula was affected, so prompt evaluation and follow-up are important.
References
- American Academy of Ophthalmology. Branch retinal vein occlusion.
- National Eye Institute (NEI). Retinal vein occlusion.
- MedlinePlus, U.S. National Library of Medicine. Retinal vein occlusion.
- American Heart Association. High blood pressure and eye health.