What is Branch Retinal Vein Occlusion?
The eye works like a camera. It has two parts, a lens, and a film. The film layer lines the back wall of the eyes and is called the retina. The part of the retina that is responsible for central vision is called the macula. It has arteries that provide blood flow and veins that drain the blood. The arteries and the veins share a common tubing. Over time, the arteries can become hardened and compress the veins. If too much force is applied, it can block a section supplied by a retinal vein. This is called a branch retinal vein occlusion (BRVO).
Complications of BRVO
The blockage may be mild and cause no vision-threatening changes or symptoms. In these cases, patients are recommended to undergo a medical evaluation by their primary care doctor and their eyes are monitored closely. In other patients, the blockage may be more severe and cause treatable vision-threatening complications such as macular edema or neovascularization.
The most common complication is macular edema. Patients with this condition generally experience a considerable improvement in vision with treatment and maintain excellent vision over the long term. Macular edema involving the area of central vision is treated with intravitreal injections. This refers to a procedure in which medication is injected into the white of the eye in a typically painless procedure.
The medication is injected every month for a period of 3-6 months. There is typically a very rapid improvement in vision within the first 3 months of treatment and then a slow improvement and stabilization of vision by 6 months. After a period of 3-6 months, the frequency of injections is either slowly decreased or injections are stopped completely. If injections are stopped completely, patients will be monitored for signs of recurring edema.
There are some patients who only need a few injections during their entire treatment and others who require treatments every four weeks for years. Retina specialists are unable to know the precise number of injections that a patient will need or for what duration. The treatment plan is tailored to the patient’s response at each visit.
Abnormal Blood Vessels
Another possible complication associated with a branch retinal vein occlusion is the development of abnormal new blood vessels within the retina. These new blood vessels leak and bleed resulting in a temporary loss of vision. The areas with the poorest blood flow are the parts of the retina responsible for creating this undesirable hormone and encouraging new blood vessel growth. This is treatable with an in-office procedure called panretinal photocoagulation, abbreviated PRP.
Why Does BRVO Occur?
Now, let’s talk about why this condition occurs and how patients may decrease the risk of a branch retinal vein occlusion in the other eye.
This condition occurs due to a hardening of the arteries. Hardening of the arteries is caused by a combination of age, high blood pressure, and or high cholesterol. While diabetes itself is not a risk factor for branch retinal vein occlusion, it can contribute to the hardening of the arteries. Therefore, patients are typically asked to undergo evaluation for diabetes. Determining if these conditions are present and controlling them if they exist will decrease the risk of the condition worsening or spreading to the fellow eye.
There are a number of uncommon causes of this condition that make up an extremely small minority of branch retinal vein occlusions. Retina specialists may order special blood tests if they think this may be the cause.
What Should Patients Watch Out For?
The new onset of worsening blurry vision may be a sign of worsening swelling in the macula. Patients should contact their retina specialist if they note worsening vision as this may be a sign that treatment is needed sooner than the next scheduled visit.
The onset of many floaters may be a sign of bleeding in the eye which may also require an evaluation and treatment prior to the next scheduled visit. Pain and headaches on the affected side may be a sign of high eye pressure. High eye pressure in this condition can be severe and require prompt treatment.
When To Contact Retina Specialists of Tampa
Untreated swelling in the macula can cause permanent vision loss if present for weeks to months without treatment. Abnormal new blood vessels can form which may bleed and temporarily decrease vision. Your eye care specialist may be able to detect these in the early stage and initiate treatment to decrease the risk of vision changes. Treatment at the correct duration helps to maximize vision.