What is a branch retinal vein occlusion (BRVO)?
Blood circulating through the retina leaves the eye by draining into the retinal veins. Smaller branch retinal veins connect to the central retinal vein, which is the main line out of the eye.
A branch retinal vein occlusion is a blockage that prevents normal blood flow. The blockage may be caused by a blood clot, by compression (squeezing) from a nearby retinal artery, or by diseases that affect the blood vessels, such as diabetes, glaucoma, high blood pressure, and atherosclerosis (hardening of the arteries).
What are the symptoms?
Sudden blurring or vision loss in all or part of one eye is the most common symptom of both types of retinal vein occlusion (branch and central). A doctor must examine your eye to determine which type you have. For some patients, the vision loss may happen gradually over a period of days or weeks, instead of suddenly. The amount of blurring or vision loss depends on how much damage to the retina has occurred.
How does a branch retinal vein occlusion affect the eye?
The effects of a branch retinal vein occlusion are often limited to the part of the retina where the branch is located. The other branches and the central retinal vein still work to keep blood flowing in the rest of the retina. A blockage in one of your branch retinal veins can cause retinal bleeding, damage nearby capillaries (small blood vessels), and deprive the retina of oxygen. When retinal capillaries are damaged it can lead to swelling of the retina (known as edema). If the edema affects the central part of the retina called the macula, it can reduce your central vision. In addition, low oxygen levels may trigger the formation of fragile new blood vessels that can also cause vision problems.
Untreated branch retinal vein occlusion can take months to heal and lead to permanent vision impairment in the affected eye.
What is a central retinal vein occlusion (CRVO)?
Blood circulating through the retina leaves the eye by draining into the retinal veins. Smaller branch retinal veins connect to the central retinal vein, which is the main blood vessel out of the eye.
A central retinal vein occlusion is a blockage that prevents normal blood flow. The blockage may be caused by a blood clot, by compression (squeezing) from a nearby retinal artery, or by diseases that affect the blood vessels, such as diabetes, glaucoma, high blood pressure, and atherosclerosis (hardening of the arteries).
What are the symptoms?
Sudden blurring or vision loss in all or part of one eye is the most common symptom of both types of retinal vein occlusion (branch and central). A doctor must examine your eye to determine which type you have. For some patients, the vision loss may happen gradually over a period of days or weeks, instead of suddenly. The amount of blurring or vision loss depends on how much damage to the retina has occurred.
How does a central retinal vein occlusion affect the eye?
A central retinal vein occlusion is serious because it affects the blood circulation of the entire retina. This can cause widespread retinal bleeding, damage capillaries (small blood vessels), and deprive the retina of oxygen.
When retinal capillaries are damaged it can lead to swelling of the retina (known as edema). If the edema affects the central part of the retina, called the macula, it can reduce your central vision. In addition, low oxygen levels may trigger the formation of fragile new blood vessels that can also cause vision problems.
The most severe form of this disease is ischemic central retinal vein occlusion. Ischemia (is-key-me-ah) means that the retina is literally starved of oxygen due to the blockage of blood flow.
Untreated central retinal vein occlusion can take months to heal and lead to permanent vision impairment in the affected eye.