The symptoms of a branch retinal vein occlusion depend on which venous branch is involved. Common symptoms include blurred vision or changes in a portion of the visual field (peripheral vision). Occasionally the branch retinal vein occlusion will affect a vein draining a portion of the retina away from the central vision and will not cause any symptoms.
Initially, after a branch retinal vein occlusion occurs, there is often a significant amount of blood within the retina that obscures complete visualization of the retina. The blood will often gradually absorb, but this may take several months. There are three other common complications of branch retinal vein occlusion that threaten vision: macular edema (swelling from leaking blood vessels), macular ischemia (loss of blood flow) and neovascularization (growth of new abnormal blood vessels in response to poor blood flow).
Several specialized tests may be performed in the office to confirm the diagnosis of BRVO. These include fluorescein angiography, ocular coherence tomography, and color fundus photographs of the retina.
Identifying and treating the risk factors for BRVO are the first steps in treatment. A multi-center study, the Branch Vein Occlusion Study, found that laser improved the visual prognosis after three years of follow-up. This study showed that eyes treated with laser were more likely to gain at least two lines of vision compared to untreated eyes. More than one laser treatment may sometimes be required. Other treatments are available as well. Intravitreal injection of medications that block the action of Vascular Endothelial Growth Factor (VEFG) such as bevacizumab (Avastin) can be helpful in treating macular edema and neovascularization. Intravitreal or periocular steroid injections may have a role as well. Some patients can develop a painless increase in their intraocular pressure as a result of steroids and need to be monitored for this. Patients with known glaucoma are at increased risk of steroid-related intraocular pressure elevation. Aspirin therapy is often recommended, in addition to a thorough systemic evaluation by a primary care provider.
Another serious potential problem in branch retinal vein occlusion is that of retinal neovascularization. In advanced cases, abnormal blood vessels grow from the retina into the vitreous gel of the eye. These vessels are very fragile and can lead to major bleeding (vitreous hemorrhage) and scar tissue formation. This will often cause floaters and an immediate, painless loss of vision. Laser photocoagulation treatment to the peripheral retina (panretinal photocoagulation) is very helpful in this situation. Laser treatment usually results in stabilization or even regression of the blood vessel growth. The bleeding will sometimes clear on its own, but if it does not, then an operation to remove the blood and the vitreous gel, called a vitrectomy, is sometimes performed. In severe cases of abnormal blood vessel growth, the retina may be pulled away from the wall of the eye (tractional retinal detachment), and this may require surgical repair.