Retinal Vein Occlusion

Most people know high blood pressure and other vascular diseases pose risks to overall health, but many may not know that high blood pressure can affect vision by damaging veins in the eye. High blood pressure is the most common condition associated with Branch Retinal Vein Occlusion (BRVO). About 10 to 12 percent of the people who have BRVO also have glaucoma (high pressure in the eye).

Branch retinal vein occlusion blocks small veins in the retina, the layer of light-sensing cells at the back of the eye (See Photo). If the blocked retinal veins are ones that nourish the macula, the part of the retina responsible for reading vision, some central vision is lost. During the course of vein occlusion, sixty percent of people will have swelling of the central macular vision area. In about one third of people, this macular swelling (edema) will remain for over one year.

BRVO causes a painless decrease in vision, resulting in misty or distorted vision. If the veins cover a large area, new abnormal vessels may grow on the retinal surface, which can bleed into the eye and cause blurred vision.

There is no cure for BRVO. Finding out what caused the blockage is the first step in treatment. Your eye doctor may recommend a period of observation, since hemorrhages and excess fluid may subside on their own. Depending on how damaged the veins are, laser surgery may help reduce the swelling and improve vision. Laser surgery may also shrink the abnormal new blood vessels that are at risk of bleeding.

If you have had a branch retinal vein occlusion, regular visits to your eye doctor are essential to protect vision.

Central retinal vein occlusion (CRVO) blocks the main vein in the retina, the light-sensitive nerve layer at the back of the eye. The blockage causes the walls of the vein to leak blood and excess fluid into the retina (See Photo). When this fluid collects in the macula-the area of the retina responsible for central vision-vision becomes blurry.

Floaters in your vision are another symptom of CRVO. When retinal blood vessels are not working properly, the retina grows new fragile vessels that leak blood into the vitreous, the fluid that fills the center of the eye. Blood in the vitreous clumps and is seen as tiny dark spots, or floaters, in the field of vision.

In severe cases of CRVO, the blocked vein causes painful pressure in the eye. Retinal vein occlusions commonly occur with glaucoma, diabetes, age-related vascular disease, high blood pressure, and blood disorders.

The first step is finding what is causing the vein blockage. There is no cure for CRVO. Your eye doctor may recommend a period of observation, since hemorrhages and excess fluid often subside on their own. Laser surgery may be effective in preventing further bleeding into the vitreous, or for treating glaucoma, but it cannot remove a hemorrhage or cure glaucoma once it is present.