A retinal vein occlusion occurs when one of the veins of the retina becomes blocked and cannot drain blood from the retina normally. This blockage leads to a backup of blood and fluid into the retina and can be seen in the retina as hemorrhages. The amount of swelling in the retina varies and depends on the degree of blockage of the retinal vein.
There are two types of retinal vein occlusion:
If the blockage involves the central vein to the retina, located at the optic nerve, it is called a central retinal vein occlusion. In these cases, hemorrhages can be scattered throughout the retina, and often the central portion of the retina, the macula, can become swollen.
If the blockage involves only one of the smaller retinal veins, it is called a branch retinal vein occlusion. In these cases, hemorrhages and swelling are limited to the area of the retina that is drained by that particular vein.
Symptoms of a retinal vein occlusion can vary based on the severity of the blockage in the vein and amount of swelling in the retina. It typically occurs in just one eye, and common symptoms include:
To lower your risk, you should do the following:
Your doctor can diagnose a CRVO or BRVO when examining your eyes based on the appearance of hemorrhages and swelling in the retina. Other diagnostic tests such as fluorescein angiogram and optical coherence tomography (OCT) can be performed to examine the degree of blockage of the vein and the amount of swelling present in the retina.
There is no cure for a vein occlusion. However, the main reason for decreased vision from a retinal vein occlusion is swelling in the central part of the retina called macular edema. Treatments for swelling include:
In mild vein occlusions, often there is no significant swelling, and no treatment is indicated. In severe cases of CRVO, abnormal blood vessels can develop that can lead to glaucoma. These cases are often treated with laser and/or injection with a medication to decrease blood vessel leakage. Some patients do require surgery to control eye pressure even after laser or injections.
