Wills Eye retina doctors are leading experts in the treatment of retinal vein occlusion with the latest clinical trials and new therapeutic approaches for this disease.
Retinal vein occlusion (RVO) is a blockage in a blood vessel of your eye that can result in vision loss. The retinal veins carry away blood from the cells of the retina. When one of these veins becomes blocked, the blood cannot drain properly (can be thought of like a 'clogged sink'). This may cause bleeding within the retina, swelling in the center of the vision and sometimes poor blood flow to the eye with possible new blood vessel growth. There are two distinct types of retinal vein occlusion :
Central retinal vein occlusion (CRVO) - a blockage in the retina's main vein.
Branch retinal vein occlusion (BRVO) - a blockage in a smaller retinal vein.
A third type is known as hemiretinal vein occlusion (HRVO) which is typically classified as a subtype of CRVO.
Arteries carry blood from the heart to various body parts, and veins return it. The retina has one major artery and one major vein, which is called the central retinal vein. Sometimes this vein can be blocked suddenly to some degree by a blood clot.
Branch Retinal Vein Occlusion (BRVO) is a blockage of one or more branches of the central retinal vein, which runs through the optic nerve.
In most cases of central retinal vein occlusion, an underlying cause is not found and we never know why it happens. It is more common in patients with glaucoma, high blood pressure, arteriosclerosis, and diabetes than it is in other people.
When the central retinal vein is blocked, the circulation through the retina is greatly reduced. There is often some degree of fluid back-up and swelling of the center of the retina which is called macular edema. When this happens, the retina doesn’t function well, and the vision becomes blurred.
Branch retinal vein occlusion is more common in patients with high blood pressure, diabetes, and atherosclerosis. Smoking is also a significant risk factor. However, in some cases, there is no apparent underlying cause. Underlying medical conditions that are considered associated risk factors such as high blood pressure require evaluation and treatment with a primary care physician.
With BRVO, the circulation of blood through the affected vein is either halted or reduced, often resulting in an accumulation of blood and fluid (macular edema) within the retinal tissue. The reduction in blood flow (ischemia) and macular edema both contribute to decreased visual acuity.
A few patients, with time, have a spontaneous improvement in vision. In most cases, however, the vision remains the same or worsens without treatment. The ultimate visual outcome cannot be predicted for anyone. In general, the more severe the occlusion and associated macular edema, the less likely the vision will improve spontaneously.
Treatment options proven to be effective in reducing macula edema and improving vision to some degree include medicines injected into the eye such as VEGF blockers (Lucentis and Avastin) and steroids (Triamcinolone and Ozurdex). Laser, eye drops, and glasses do not help to improve vision.
While BRVO cannot be cured, there are effective treatments that can help patients maintain or improve their visual outcome by reducing the associated macular edema. Treatment options include intravitreal injection (injection of medicine into the eye) and laser.
Intravitreal injection of vascular endothelial growth factor (VEGF) inhibitors such as Lucentis (FDA approved), Eylea (FDA approved), and Avastin (used off-label) or steroids such as triamcinolone and Ozurdex (FDA approved) can help maintain or improve vision.
Laser is sometimes used to treat macular edema but is now considered a second-line treatment for most cases based on visual outcomes and limitations. For instance, if there is significant hemorrhage in the retina, laser cannot be performed until the hemorrhage resolves spontaneously, which may take a few months.
Wills Eye Retina specialists are in the forefront of research efforts, participating in multiple clinical trials to investigate new forms of treatment for retinal vein occlusion and a variety of other retinal conditions.
These new medical compounds are being studied to determine their efficacy and safety in comparison to the current standard anti-vascular endothelial growth factor (VEGF) agents. Administered by intravitreal injection, they may potentially achieve a longer therapeutic effect.