Branch Retinal Vein Occlusion (BRVO) is a common eye condition that impacts vision. It occurs when one of the small veins in the retina, the light-sensitive tissue at the back of the eye, becomes blocked. This blockage can lead to various visual disturbances.
Understanding BRVO
The retina is a delicate layer of tissue lining the back of the eye, responsible for converting light into electrical signals that are sent to the brain, allowing us to see. In the retina, a network of arteries delivers oxygen-rich blood, and veins carry deoxygenated blood away. When a branch retinal vein occlusion occurs, one of these smaller veins becomes blocked. This blockage prevents blood from properly draining from the affected area. Blood and fluid then leak out of the engorged vein and accumulate within the retinal tissue. This accumulation of fluid, particularly if it affects the macula—the central part of the retina responsible for sharp, detailed vision—can significantly impair visual acuity.
Causes and Risk Factors
Several underlying health conditions can contribute to the development of branch retinal vein occlusion. High blood pressure is a frequent contributor because it can cause the walls of blood vessels to thicken and harden. This hardening can lead to the compression of retinal veins where they cross paths with arteries, making blockages more likely.
Diabetes is another significant risk factor, as it can damage blood vessels throughout the body, including those in the retina. High cholesterol levels can also contribute to the narrowing and hardening of arteries, further increasing the risk of a blockage. Glaucoma, characterized by increased pressure within the eye, can also play a role by potentially compressing retinal veins. Advancing age is a non-modifiable risk factor, with the incidence of BRVO increasing as individuals get older.
Recognizing the Signs
The visual changes associated with branch retinal vein occlusion typically manifest suddenly and are often painless. Individuals might experience blurred vision, where objects appear out of focus, or distorted vision, causing straight lines to appear wavy or bent. A dark or blind spot might also appear in the field of vision. Some people may notice partial vision loss in one eye, affecting either the central or peripheral vision depending on the location of the blockage. Because these symptoms can mimic other eye conditions, prompt medical evaluation is important.
Diagnosis and Treatment
Diagnosing branch retinal vein occlusion begins with a comprehensive dilated eye examination. Optical coherence tomography (OCT) is a non-invasive imaging test used to create cross-sectional images of the retina, which helps detect and measure any swelling, particularly in the macula. Fluorescein angiography is another diagnostic tool where a dye is injected into a vein, allowing the doctor to visualize blood flow in the retina and identify leaky blood vessels.
Treatment for BRVO primarily aims to reduce macular swelling and prevent further vision loss. Anti-VEGF (vascular endothelial growth factor) injections are the most common treatment, involving medications such as aflibercept, ranibizumab, or bevacizumab administered directly into the eye. These medications work by blocking a protein that contributes to abnormal blood vessel growth and leakage. In specific cases, such as the development of new, fragile blood vessels, laser photocoagulation may be used to seal off leaky vessels and prevent bleeding. The treatment plan is customized for each patient, considering the severity and location of the occlusion.
Living with BRVO
Living with branch retinal vein occlusion often requires ongoing monitoring by an eye care professional to track the condition and the effectiveness of treatment. While many patients experience an improvement in their vision with appropriate treatment, some may have some residual visual impairment. Regular follow-up appointments are important to manage any potential long-term effects and adjust treatment as needed.
Managing underlying health conditions, such as high blood pressure or diabetes, is also crucial in preventing recurrence of BRVO in the same eye or the other eye. Long-term complications, including chronic macular edema or the development of new, abnormal blood vessels (neovascularization), can occur. These complications are typically managed with continued anti-VEGF injections or laser therapy.