Most people know that 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 the veins in the eye. High blood pressure is the most common condition associated with branch retinal vein occlusion (BRVO). About 10% to 12% of the people who have BRVO also have glaucoma (high pressure in the eye).
BRVO blocks small veins in the retina, the layer of light-sensing cells at the back of the eye. If the blocked retinal veins are ones that nourish the macula, the part of the retina responsible for straight-ahead vision, some central vision is lost. During the course of vein occlusion, 60% or more will have swelling of the central macular area. In about one-third of people, this macular edema will last for more than 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 ophthalmologist 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 abnormal new blood vessels that can grow and that are at risk of bleeding. Newer injectable medicines are being investigated for treating BRVO.
If you have had a branch retinal vein occlusion, regular visits to your ophthalmologist or optometrist are essential to protect vision.