Retinal Vein Occlusion
Branch retinal vein occlusion (BRVO) is a condition when retinal vein blood flow is impeded. In a BRVO, the blood outflow is generally restricted in one part of the retina. If the main retina vein of the eye’s blood flow is restricted then that is called central retinal vein occlusion (CRVO). A CRVO can include the whole retina usually resulting in more profound vision loss.
The retinal blood supply comprises of arteries and veins. Arteries supply blood to the retina and veins take blood away from the retina. Blockages, in a retinal vein, can happen for different reasons. The most common reason behind a retinal vascular blockage is atherosclerosis, or “solidifying of the veins”, which happens with advancing age, hypertension, or elevated cholesterol.
At the point when a retinal vein is blocked it results in back tension in the veins and bleeding and swelling into the retinal tissue. If blood and edema develop in the focusing point of the retina (macula) then vision declines. Back pressure in the veins can also cause decrease in blood supply to the macula causing decrease oxygen supply to the macula. This is called macular ischemia and can result in long lasting vision decline.
The diagnosis of a retinal vein occlusion can generally be made by clinical assessment of the retina. Fluorescein angiography is a valuable diagnostic tool to assess the severity of the edema and ischemia. Optical coherence tomography (OCT) can be utilized to record the thickness and measure the swelling in the macula.
Treatment and Prognosis
Many patients with retinal vein occlusion may benefit from treatment. Laser treatment and intraocular injection are both used to treat retinal vein occlusion related retina problems. Laser treatment is utilized to reduce the edema in the macula in patients with branch retinal vein occlusion and to suppress development of abnormal blood vessels (neovascularization) in patients with central and branch retinal vein occlusion. Laser treatment, intraocular injections with drugs, for example, steroids, Lucentis®, Avastin®, and Eylea® are additionally utilized medicines for macular edema in central and branch retinal vein occlusion. Not all patients with retinal vein occlusion require treatment, and close observation by an eye specialist may be the only thing required. The visual prognosis for CRVO and BRVO depends essentially on the severity of the occlusion.