Retinal vein occlusion is most often caused by hardening of the arteries (atherosclerosis) and the formation of a blood clot.

Blockage of smaller veins (branch veins or BRVO) in the retina often occurs in places where retinal arteries that have been thickened or hardened by atherosclerosis cross over and place pressure on a retinal vein.

Risk factors for retinal vein occlusion include:

• Atherosclerosis
• Diabetes
• High blood pressure (hypertension)
• Other eye conditions, such as glaucoma, macular edema, or vitreous hemorrhage

The risk of these disorders increases with age, therefore retinal vein occlusion most often affects older people.

Blockage of retinal veins may cause other eye problems, including:

• Glaucoma (high pressure in the eye), caused by new, abnormal blood vessels growing in the front part of the eye
• Macular edema, caused by the leakage of fluid in the retina

Symptoms include sudden blurring or vision loss in all or part of one eye.

Tests to evaluate for retinal vein occlusion include:

• Exam of the retina after dilating the pupil
• Fluorescein angiography
• Intraocular pressure
• Pupil reflex response
• Refraction eye exam
• Retinal photography
• Slit lamp examination
• Testing of side vision (visual field examination)
• Visual acuity test to determine the smallest letters you can read on a chart

Other tests may include:

• Blood tests for diabetes, high cholesterol, and triglyceride levels
• Blood tests to look for a clotting or blood thickening (hyperviscosity) problem (in people under age 40 years)

The health care provider will closely monitor any blockage for several months. Some harmful effects, such as glaucoma, may take 3 or more months to develop after the occlusion.

Many people will regain vision, even without treatment. However, vision rarely returns to normal. There is no way to reverse or open the blockage.

You may need treatment to prevent another blockage from forming in the same or the other eye.

• It's important to manage diabetes, high blood pressure, and high cholesterol levels.
• Some people may need to take aspirin or other blood thinners.

Treatment for the complications of retinal vein occlusion may include:

• Focal laser treatment, if macular edema is present.
• Injections of anti-vascular endothelial growth factor (anti-VEGF) drugs into the eye. These drugs may block the growth of new blood vessels that can cause glaucoma.
• Laser treatment to prevent the growth of new, abnormal blood vessels that leads to glaucoma.

The outcome varies. People with retinal vein occlusion often regain useful vision.

It is important to properly manage conditions such as macular edema and glaucoma. However, having either of these complications is more likely to lead to a poor outcome.

Complications may include:

• Glaucoma
• Partial or complete vision loss in the affected eye

Contact your provider if you have sudden blurring or vision loss.

Retinal vein occlusion is a sign of a general blood vessel (vascular) disease. Measures used to prevent other blood vessel diseases may decrease the risk for retinal vein occlusion.

These measures include:

• Eating a low-fat diet
• Getting regular exercise
• Maintaining an ideal weight
• Not smoking

Aspirin or other blood thinners may help prevent blockages in the other eye.

Controlling diabetes may help prevent retinal vein occlusion.

Central retinal vein occlusion; CRVO; Branch retinal vein occlusion; BRVO; Vision loss - retinal vein occlusion; Blurry vision - retinal vein occlusion

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Flaxel CJ, Adelman RA, Bailey ST, et al. Retinal vein occlusions preferred practice pattern. Ophthalmology. 2020;127(2):P288-P320. PMID: 31757503 pubmed.ncbi.nlm.nih.gov/31757503/.

Freund KB, Sarraf D, Mieler WF, Yanuzzi LA. Retinal vascular disease. In: Freund KB, Sarraf D, Mieler WF, Yannuzzi LA, eds. The Retinal Atlas. 2nd ed. Philadelphia, PA: Elsevier; 2017:chap 6.

Guluma K, Lee JE. Ophthalmology. In: Walls RM, ed. Rosen's Emergency Medicine: Concepts and Clinical Practice. 10th ed. Philadelphia, PA: Elsevier; 2023:chap 57.

Jeng-Miller KW, Desai SJ, Chen X, Heier JS. Venous occlusive disease of the retina. In: Yanoff M, Duker JS, eds. Ophthalmology. 6th ed. Philadelphia, PA: Elsevier; 2023:chap 6.16.

Updated by: Audrey Tai, DO, MS, Athena Eye Care, Mission Viejo, CA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.