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Blockage of Central Retinal Veins and Branch Retinal Veins

(Retinal Vein Occlusion; Branch Vein Occlusion)


Sonia Mehta

, MD, Vitreoretinal Diseases and Surgery Service, Wills Eye Hospital, Sidney Kimmel Medical College at Thomas Jefferson University

Reviewed/Revised Apr 2022 | Modified Sep 2022
Topic Resources

A vein in the retina (the transparent, light-sensitive structure at the back of the eye) may become blocked, causing sudden, painless loss of vision.

  • Doctors typically make the diagnosis by looking in the eye with an ophthalmoscope and sometimes by diagnostic tests.

  • Treatment can often improve vision.

The central retinal vein is the main vein that drains blood away from the retina. Blockage may occur in the main vein or in its branches.

The Retina and Optic Nerve

Central retinal vein blockage occurs mainly in older people. Risk factors include

  • High blood pressure

  • Glaucoma

  • Diabetes

  • Increased blood viscosity (thickness)

Sometimes the cause of the blockage is unknown.


Blockage of the central retinal vein causes severe, painless, and usually sudden loss of vision, but vision loss can also sometimes occur gradually over a period of days to weeks.

Blockage of the central retinal vein may also cause growth of abnormal blood vessels on the retina or iris. Sometimes, these abnormal blood vessels bleed or cause a painful type of glaucoma (called neovascular glaucoma). In neovascular glaucoma, abnormal blood vessels that have formed in the iris close the space between the iris and the cornea, blocking the drainage of fluid from the eye and causing buildup of pressure in the eye (glaucoma Glaucoma Glaucomas are a group of eye disorders characterized by progressive optic nerve damage (often, but not always, associated with increased eye pressure) that can lead to irreversible loss of vision... read more ).


  • A doctor's examination of the eye

  • Fluorescein angiography

  • Optical coherence tomography

  • Sometimes other tests

Using an ophthalmoscope, doctors can see changes in blood vessels and the retina. If the central retinal vein is blocked, the veins may be engorged (appearing enlarged), bleeding spots may be visible scattered throughout the retina, and the front of the optic nerve may be swollen.

Fluorescein angiography Angiography A variety of tests can be done to confirm an eye problem or to determine the extent or severity of an eye disorder. Each eye is tested separately. In general, angiography involves injecting... read more helps determine the extent of damage to the retina and helps the doctor plan treatment. In this test, a doctor injects dye into a vein in the arm and then photographs the retina. The dye makes the blood vessels of the retina show up better in the photograph. Optical coherence tomography Optical Coherence Tomography A variety of tests can be done to confirm an eye problem or to determine the extent or severity of an eye disorder. Each eye is tested separately. In general, angiography involves injecting... read more (an imaging study) can help show that the retina is swollen, which is common.


How much vision people retain depends mainly on two things:

  • Whether the blockage affected the central retinal vein or a branch

  • Sharpness of vision (visual acuity) at the time of the blockage

Most people have some permanent loss of vision.

If the visual acuity is good at the time of retinal vein blockage (usually when only a branch is blocked), it will likely remain good, occasionally near normal. If the visual acuity is poor (for example, worse than 20/200), it will remain poor or worsen in 80% of people. Blockage of the central retinal vein rarely recurs.


  • Drugs injected into the eye

  • Laser treatment of abnormal or bleeding blood vessels

Certain drugs can be injected into the eye, or an implant that slowly releases constant levels of a corticosteroid can be injected into the eye. Laser treatment of the leaking blood vessels can also help improve vision for some people with a blockage in a branch of the retinal vein. Although the treatments help restore vision in a number of people, many people have some permanent vision loss. Thus, preventing such blockages by controlling risk factors (for example, high blood pressure, diabetes, and other risk factors for atherosclerosis) is desirable.

Laser treatment may be used to destroy abnormal blood vessels to treat or prevent neovascular glaucoma or prevent further vision loss from bleeding within the eye.

More Information

The following is an English-language resource that may be useful. Please note that THE MANUAL is not responsible for the content of this resource.

    • National Eye Institute: A resource for learning about eye health (in English and Spanish) for adults and children, as well as access to outreach campaigns.

Drugs Mentioned In This Article

Generic Name Select Brand Names
AK-Fluor, Bio Glo, Fluorescite, Fluorets , Fluor-I-Strip, Fluor-I-Strip A.T., Ful-Glo, Ophthalmicflur
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