Branch Retinal Vein Occlusion (BRVO) is similar to a central retinal vein occlusion, but only affects a segment of the retina. A BRVO occurs when a branch of the retinal vein becomes blocked. The blockage usually occurs where a retinal artery crosses over and compresses a retinal vein. The segment of the retina drained by the blocked vein becomes swollen with blood. Where the vessel is blocked it often leaks, causing retinal swelling. When swelling occurs in the central retina it is called macular edema, and may result in loss of vision. As in CRVO, vision loss can also occur if abnormal blood vessels grow in the front or back of the eye.

Branch Retinal Vein Occlusion

Symptoms
Patients with a BRVO often have blurred vision from retinal hemorrhage or macular edema. Occasionally spots, strands or a curtain may occur due to vitreous hemorrhage. Eye pain may be caused by neovascular glaucoma.

Fluorescein Angiography of BRVO Laser Treatment of BRVO BRVO After Laser Treatment

Evaluation
In addition to a dilated eye exam, a test called Fluorescein Angiography may be required. During this test a dye is injected into a vein in the arm. Special photographs are taken of the retina as the dye passes through the eye. Blocked or abnormal blood vessels will become detectable to the physician. Optical Coherence Tomography (OCT) may be performed to determine if macular edema is present. These tests aid the diagnosis and may help determine the need for laser treatment.

Treatment
If vision loss is due to macular edema, laser treatment may be recommended. Laser treatment will decrease the leakage which is causing macular edema. Studies have shown that patients who receive laser for macular edema are twice as likely to regain good vision. If abnormal blood vessels are growing in the eye, more extensive laser treatment may be necessary. Medications placed into the eye may also be recommended to cause regression of new blood vessels and resolution of macular edema (see section on Intravitreal Drug Therapy).

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