Blood vessels carry blood to and from the light sensitive structure of the eye called the retina. In particular blood in the retina is drained from smaller branches of retinal veins (venules) into the larger central retinal vein away from the eye. Either one or more of the smaller branches of the main, larger central retinal vein can become blocked or obstructed. Usually there is a painless loss of some peripheral an/or central vision.

Retinal venous disease can be among the top leading five causes of vision loss in the elderly in our practice. The average age of presentation is 65 years old with 85 percent of the patients above the age of 50. Similar to certain types of stroke, a partial blockage or obstruction within the blood vessel impedes the outflow of blood from the eye. Subsequently there is associated bleeding, swelling or edema into the retina. In some cases the blood flow within the smallest blood vessels called capillaries is compromised resulting in poor circulation or ischemia of the retina. If the central portion of the retina known as the macula is affected by any of these 3 complications, that is blood, edema, or ischemia, there may be irreversible loss of vision.

In patients over the age of 50, the blockage within the retinal vein typically occurs because of arteriosclerosis (hardening of the arteries). This leads to turbulent blood flow within the vein and in some cases leads to the development of a clot in the vein. I should emphasize that the clot develops within the retinal vein and does not pass to the eye from another part of the body such as the heart or carotid artery. In patients under the age of fifty, sometimes either inflammation or coagulation (clotting) disorders may pre-dispose to the development of clot and subsequent vascular obstruction. We usually recommend a more comprehensive evaluation (mostly blood tests) in younger patients who are diagnosed with this condition.

Branch Retinal Vein Obstruction occurs because of a blockage of one of the branches of the central retinal vein. About 1 in 3 patients with a BRVO have reading vision and about 1 in 4 patients have severe loss of central vision (20/200) in the affected eye. Upwards of 10 percent of patients with a branch retinal vein obstruction can develop bleeding in the eye from development of abnormal new blood vessels. If there's still persistent retinal swelling or macular edema after 3-4 months of symptoms associated with reduced vision, then macular laser photocoagulation may be indicated. About 60 percent of patients obtained reading vision after laser photocoagulation; however, at least 12 percent remained worse than 20/200. In these rare cases, if there is associated bleeding associated with a development of new bloody vessels then laser photocoagulation may also be indicated. In more severe cases which are refractory to conservative treatment, new surgical techniques are under investigation. During vitrectomy surgery, the artery and vein are physically separated from each other, allowing decompression of the branch vein obstruction. Often there is improved in perfusion in the vein with subsequent amelioration of the circulation and macular edema.

Central Retinal Vein Obstruction is caused by a blockage of central retinal vein as it exits the eye. About 25 percent of patients will have a severely compromised circulation or ischemia. Most of these patients have poor vision. The other 75% of patients need to also be followed carefully for any exacerbation with the development of ischemic changes. Patients with an ischemic type of central retinal vein obstruction are followed on the frequent basis for the development of complications. Complications associated with the blood vessel growth can lead to bleeding in the central eye cavity and/or blood vessel growth on the iris which can lead to a severe type of glaucoma called neovascular glaucoma. In certain cases laser photocoagulation is indicated to treat or in the most severe cases prevent the development of these new blood vessel growth which can lead to subsequent complications. If laser photocoagulation is indicated, it is applied as scatter treatment over one or several visits to ablate or destroy as much as of the ischemic retina as possible without treating the macula. In people with a central retinal vein obstruction with severe macular edema, macular laser has not shown to be of any significant benefit. There are also currently some other treatments under investigation, but unfortunately none of these investigational treatments have shown conclusively any significant benefit to date. Your ophthalmologist can discuss the experimental treatment available.