Branch retinal vein occlusion or BRVO is often referred to as an “eye stroke” and can impact a person’s ability to see. The degree of vision loss varies in each sufferer. There are some cases where a person can recover from BRVO. Here we look at the causes as well as recovery and treatment.
An “eye stroke” sounds frightening, but just what is branch retinal vein occlusion? Well, in simple terms, it is a blockage in one of the veins that return blood from your retina back to your heart. The retina serves an important function—it converts light and images into nerve signals and sends them to our brain through the optic nerve. If anyone has blockages due to blood clots or fluid build-up in their retinal veins, it makes it difficult for the retina to filter light, impacting vision. The extent of vision loss depends on which vein is blocked.
There are two types of retinal veins. We have one central vein as well as several smaller branch veins. There are also two types of retinal vein occlusion: central retinal vein occlusion and branch retinal vein occlusion. The only difference between the two is the location of the blockage and the area that can be damaged. In this case, one of the branches is blocked.
What are the causes and risk factors of branch retinal vein occlusion?
Branch retinal vein occlusion causes vary, but most BVRO causes relate to an artery and a vein—more specifically, to an intersection between a retinal artery and vein. These vessels share a common connective tissue, and when the artery loses flexibility, the vein becomes compressed. A narrow vein can impact blood flow, leading to clotting, which causes a blockage (occlusion). Sometimes the blockage prevents blood drainage and then fluid leaks into the center of vision. This is called macular edema. It can also cause poor blood flow to vessels supplying the macula.
Here are the most common BVRO risk factors:
- Uncontrolled high blood pressure
- Cardiovascular disease
- Arteriosclerosis (hardening of the arteries)
- Being overweight or obese
- Age (significant link to advancing age with BVRO)
- Hyperlipidemia (high concentration of fats or lipids in the blood)
- Hyperhomocysteinemia (high level of amino acids found in blood plasma)
- Anti-cardiolipin antibodies (an antibody that is found in a number of autoimmune and infectious diseases)
Retinal vein occlusion is the second most common retinal vascular disorder after diabetic retinopathy, which is a complication of diabetes that affects the eyes. Some studies suggest that up to two percent of the US population may be suffering from BRVO.
What are the symptoms of branch retinal vein occlusion?
Branch retinal vein occlusion symptoms go beyond vision loss. Some people notice what is commonly called floaters. These are really dark spots or lines in your vision. The floaters are clumps of blood leaking into the vitreous from retinal vessels.
When it comes to vision loss, it can happen suddenly or it can occur over several hours or days. Branch retinal vein occlusion is usually just in one eye.
If you notice any BRVO symptoms or any other unusual eye symptoms, you should seek medical attention immediately.
Complications of BRVO
One problem that some patients face months or even years after being diagnosed with BVRO is that they develop an abnormal growth of delicate new blood vessels on the surface of their retina. While these vessels don’t appear with any symptoms, if they rupture and bleed, it can lead to significant vision loss. The blood that gets into the vitreous cavity of the eye usually clears up on its own, but it can take weeks or months for this to happen.
Generally, when these tiny blood vessels develop, a laser treatment can be used to lower the risk of bleeding. While there is no guarantee that more fragile vessels won’t form in the future, it does lower the risk significantly. In cases where there happens to be a large hemorrhage, surgery may be needed to remove the blood from the vitreous cavity. This procedure is called a vitrectomy.
Diagnosis of branch retinal vein occlusion
BVRO is diagnosed following a complete eye examination. The doctor will pay close attention to any history of glaucoma, intraocular inflammation, or possible risk factors that the patient may have.
There are specific tests that can be conducted for branch retinal vein occlusion diagnosis, including the following:
- Fluorescein angiography (FA): Fluorescent dye is injected into the bloodstream to help highlight blood vessels in the back of the eye. This procedure is used to help characterize the retinal issues, such as leakage or edema. Depending on the extent of bleeding, some cases can be hard to read with FA.
- Optical coherence tomography (OCT): This uses light waves to get a cross-section picture of the retina. It allows an ophthalmologist to see each distinct layer of the retina. It is considered fast and non-invasive. Unlike FA, OCT testing isn’t really affected by the amount of bleeding.
- Laboratory test: This consists of a metabolic panel, complete blood count, as well as a lipid panel to help highlight known risk factors.
In patients younger than 50, other tests to determine cause may be administered. This could include searching for signs of an infection or inflammation. Doctors will also want to take a look at any medications a patient might be taking to see if they affect symptoms.
What are the treatment options for BRVO?
Those who are wondering about branch retinal vein occlusion treatment first must understand that it is a condition that really can’t be 100 percent cured. The main goal of BVRO treatment is to keep an individual’s vision as stable as possible. Sealing off any leaking blood vessels in the retina is standard, as it can prevent further swelling of the macula and further vision loss.
Branch retinal vein occlusion treatment guidelines include stopping fluid from leaking from vessels and treating the patient with appropriate medications. An ophthalmologist may suggest a laser procedure to stop fluid from leaking from the vessels. They may also choose to use medications injected into the eye. These injections are usually a medicine called “anti-VEGF.” They are able to improve vision in one out of every two patients. The downside is that the injections need to be administered regularly for one to two years for any benefit to last.
No matter what the treatment for BVRO, it normally takes a few months for the patient to experience vision improvement.
Prevention and prognosis of BRVO
So, what is the branch retinal vein occlusion prognosis? If vision is reduced, it is important to understand that it has the potential for returning, at least in part, over the next few months. On the upside, many people find that the degree of impairment they experience is minimal, and when treatment is applied, they feel as if they have almost returned to normal. The truth is that BRVO prognosis really depends on the severity of damage.
When someone has been diagnosed with branch retinal vein occlusion, they can still participate in activities, such as reading and watching TV, but depth perception can be hampered with blurred vision in one eye. Care should be taken when doing anything requiring the judgment of distance, such as climbing stairs or ladders, driving, and pouring hot drinks.
It is interesting to note that not all cases of BRVO cause loss of vision. When it comes to BRVO prevention, the best advice we can give is to make sure you get regular eye exams. Eyesight needs to be checked regularly for any complications that could impact vision.
While there is no specific data on the number of severe cases of BRVO, we are led to believe that the majority of people who suffer from this eye condition experience mild to moderate symptoms. In just about every case, eye doctors tell patients not to overthink their recovery. Though those who experience a great deal of anxiety around their condition should reach out to their doctor.