Similar to a CRVO, branch vein occlusions occur when the retinal vein occludes or gets constricted. The occlusion causes blood and fluid to leak out into the affected retina. If the central macula is involved, macular edema develops and causes loss of central vision.
There are 4 types of retinal vascular occlusions (RVO):
- Branch retinal vein occlusion
- Central retinal vein occlusion
- Branch retinal artery occlusion
- Central retinal artery occlusion
Symptoms of BRVO
Painless loss of vision are the common symptoms of this type occlusion. Central vision is lost if the macula is involved.
Unlike the “central” counterpart, vision loss is often not as severe and, perhaps, not as globally affected (due to the fact that the entire retina is not involved). Most of the time, 50% of the retina is involved and does include the macula.
Once in a while, a patient is asymptomatic - not knowing anything is wrong. In these cases, the macula is not affected and only a small portion of the retina is affected by the occluded vein.
Treatment and Prognosis
For years, the only treatment available for BRVO was laser. The laser was moderately successful in reducing overall retinal swelling. Treatment of macular swelling was limited.
In addition to laser, several additional treatments are available. Many seem to be more effective in treating macular edema from BRVO.
Treatment of branch vein occlusions is aimed at treating the macular edema. The macular edema is very responsive to treatment and the visual prognosis is the best compared to other types of RVO.
anti-VEGF medications include Eylea, Lucentis and Avastin. These are delivered by injections.
Steroids are also very effective and include Kenalog, Triamcinolone and Ozurdex. Ozurdex is a unique sustained release form of steroid that may last for up to 6 months. Iluvien is a similar sustained release medication but is not FDA approved for RVO. All steroids are delivered via intravitreal injection.