Retinal vein occlusion: MedlinePlus Medical Encyclopedia

P Retinal vein occlusion is a blockage of the small veins that carry blood away from the retina. The retina is the layer of tissue at the back of the inner eye that converts light images to nerve signals and sends them to the brain.

T Causes
P Retinal vein occlusion is most often caused by hardening of the arteries (atherosclerosis) and the formation of a blood clot.
P 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.
P Risk factors for retinal vein occlusion include:
- Atherosclerosis
- Diabetes
- High blood pressure (hypertension)
- Other eye conditions, such as glaucoma, macular edema, or vitreous hemorrhage
P The risk of these disorders increases with age, therefore retinal vein occlusion most often affects older people.
P 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

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

T Exams and Tests
P Tests to evaluate for vein occlusion include:
- Exam of the retina after dilating the pupil
P An eye test that uses a special dye and camera to look at blood flow in the retina and choroid.
- Intraocular pressure
- Pupil reflex response
- An eye exam that measures a person's prescription for eyeglasses or contact lenses
- 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
P 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 patients under age 40)
P The health care provider will closely monitor any blockage for several months. It may take 3 or more months for harmful effects such as glaucoma to develop after the occlusion.

T Treatment
P Many people will regain vision, even without treatment. However, vision rarely returns to normal. There is no way to reverse or open the blockage.
P 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.
P 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. This treatment is still being studied.
- Laser treatment to prevent the growth of new, abnormal blood vessels that leads to glaucoma.

T Outlook (Prognosis)
P The outcome varies. Patients with retinal vein occlusion often regain useful vision.
P 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.

T Possible Complications
P Complications may include:
- Glaucoma
- Partial or complete vision loss in the affected eye

T When to Contact a Medical Professional
P Call your provider if you have sudden blurring or vision loss.

T Prevention
P 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 of retinal vein occlusion.
P These measures include:
- Eating a low-fat diet
- Getting regular exercise
- Maintaining an ideal weight
- Not smoking
P Aspirin or other blood thinners may help prevent blockages in the other eye.
P Controlling diabetes may help prevent retinal vein occlusion.

T Alternative Names
P Central retinal vein occlusion; Branch retinal vein occlusion; CRVO; BRVO; Vision loss - retinal vein occlusion; Blurry vision - retinal vein occlusion

T References
P Crouch ER, Crouch ER, Grant TR. Ophthalmology. In: Rakel RE, ed. Textbook of Family Medicine. 9th ed. Philadelphia, PA: Saunders Elsevier; 2016:chap 17.
P Crouch ER, Crouch ER, Grant TR. Ophthalmology. In: Rakel RE, ed. Textbook of Family Medicine. 8th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 41.
P Goldman DR, Shah CP, Morley MG, Heier JS. Venous occlusive disease of the retina. In: Yanoff M, Duker JS, eds. Ophthalmology. 4th ed. Philadelphia, PA: Elsevier Saunders; 2014:chap 6.19.
P Kreutzer TC, Alge CS, Wolf AH, et al. Intravitreal bevacizumab for the treatment of macular oedema secondary to branch retinal vein occlusion. Br J Ophthalmol. 2008;92:351-355. PMID: 18211925 www.ncbi.nlm.nih.gov/pubmed/18211925.
P Quiros PA. Urgent neuro-ophthalmic disorders. In: Yanoff M, Duker JS, eds. Ophthalmology. 4th ed. Philadelphia, PA: Elsevier Saunders; 2014:chap 9.24.
P Reiss GR, Sipperley JO, Gaitan JR. Glaucoma associated with retinal disorders and retinal surgery. In: Tasman W, Jaeger EA, eds. Duane's Clinical Ophthalmology. 2013 ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2013:vol 3; chap 54E.

T Review Date 3/15/2016
P Updated by: Franklin W. Lusby, MD, ophthalmologist, Lusby Vision Institute, La Jolla, CA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

