A retinal vein occlusion (RVO) refers to occlusion of a blood vessel in your eye, similar to what happens in the brain during a stroke. This is why people refer to RVO as an “eye stroke”. Usually a blood clot blocks a retinal vein leading to obstruction of blood flow in it. If this affects the central part of the retina, which is responsible for high definition vision, it can cause loss of vision.
RVO usually occurs in older people with risk factors such as high blood pressure, diabetes and glaucoma. The condition may also develop in young people due to dehydration, clotting disorders, birth control pills as well as other reasons.
The condition occurs in two forms depending on the topographic extent of retinal involvement:
When a branch of the main retinal vein is blocked we call this branch retinal vein occlusion (BRVO). In this condition only a portion of the retina is damaged.
In contradistinction, when the main retinal vein is occluded, the entire retina is damaged and we call this central retinal vein occlusion (CRVO).

When retinal vein occlusion develops, the symptoms can be variable. You may experience blurriness or slight vision loss, while other people may experience complete loss of vision almost immediately. With mild RVO, you may retain some vision or may regain your vision.

Associated with the occlusion, the blood vessels may become leaky causing retinal swelling. Also abnormal new blood vessels may start to form, which can bleed. The clot in a retinal vein cannot be removed, so treatment focuses on managing the leakage or the abnormal blood vessels associated with the occlusion.

Your retinal specialist will initially perform a full eye exam and gather a complete health history to try to determine the cause of the RVO. He may also measure your blood pressure. Your doctor may also order blood tests since some blood problems can lead to RVO.
In addition, an optical coherence tomography (OCT) is obtained to assess the RVO. The OCT allows us to obtain a cross sectional views of the macula with three-dimensional images. It is important for measuring the amount of leakage and retinal swelling, treatment planning and for monitoring treatment outcomes.
Fluorescein angiography may also be performed. This test shows changes in the structure or function of retinal blood vessels as well as the site of occlusion. In this procedure, a dye is injected into a vein in your arm, and then the dye circulates through your body. As it transits through your eyes, photographs of your retina are taken as the dye outlines your retinal blood vessels.

Treatment options:
This serious eye condition can lead to blindness and even loss of the eye through development of severe bleeding in the eye, retinal detachment or severe glaucoma. Therefore, it should be managed by a retina specialist and not a general ophthalmologist. Not every ophthalmologist is a retina specialist that is experienced in managing this condition. Controlling blood pressure and other systemic risk factors such as diabetes or clotting problems help prevent retinal blood clots and preserve your sight.
Local ocular treatment may include observation if the condition is mild and not affecting vision, or just minimally affecting vision. Other treatment options in case of more severe RVO and vision loss include laser treatment or injections inside the eye to minimize leakage into the macula or cause regression of abnormal blood vessels forming on the retinal surface. Surgery may also be needed in case severe bleeding inside the eye or retinal detachment develops. If glaucoma develops, additional medications or even surgery maybe needed to control the glaucoma and eye pressure.