Retinal Vein & Artery Occlusions
When it comes to your vision, particularly your retina, any disruptions to normal function can be serious. For example, if occlusions (blockages) cut off the retina’s supply of oxygen-rich blood, this can be very harmful to your eye and vision health. Retinal vein occlusions (RVOs) or retinal artery occlusions (RAOs), as they’re known, may result in eye inflammation and swelling. As the damage worsens, abnormal new blood vessels can grow and permanent vision loss may occur. Generally, RAOs and RVOs conditions occur suddenly, with no pain. However, retinal occlusions are considered medical emergencies; immediate medical treatment is essential and may enable you to preserve some vision.
Although RAOs and RVOs are incurable conditions, their underlying conditions and risk factors can be effectively managed. Certain treatment options, such as injectable medications and laser therapy, may be recommended by your retina specialist.
Retinal Vein and Artery Occlusions: An Anatomical Overview
Think of the circulatory system as an ever-moving transportation route, like a train or bus line, with the heart serving as the main station. From the heart, your arteries carry oxygenated blood throughout the body, delivering their precious cargo to countless cells, tissue, and organs, including your eyes. Simultaneously, your veins are continuously returning the used blood back to the heart.
This oxygenated blood travels to and from your eyes occurs on a special pathway, known as the retinal vascular system. The main components are the central retinal artery, which extends from the neck’s internal carotid artery, and the central retinal vein. Within the retina, a thin tissue layer in the back of the eyes, these arteries and veins travel together, becoming smaller and binding to each other. Should vein or artery occlusions form, typically due to blood clot formation or a fatty deposit, the retina can be deprived of oxygenated blood.
Common Causes of Retinal Vein and Artery Occlusions
Among the more likely causes of RVOs is the eye’s veins being too narrow. RVOs may also accompany conditions affecting blood flow, such as diabetes, high blood pressure, or high cholesterol. As for RAOs, blood clots and fatty deposits are the primary contributing causes, especially if atherosclerosis (hardening of the arteries) has affected the blood vessels of the eye. RAOs may also develop when clots from other areas, primarily the heart and the carotid artery, obstruct a retinal artery or branch. Heart-related issues, like those affecting valves or rhythm (e.g., atrial fibrillation), intravenous drug abuse, or immune response concerns can also contribute to RAOs.
Types of Retinal Occlusive Diseases
In terms of the type of retina vein and artery occlusions, there are multiple designations, based on their location within the retinal vasculature and the specific artery or vein affected.
Central Retinal Artery Occlusion
A central retinal artery occlusion (CRAO), in which an obstruction affects an entire eye, is a serious condition. Also referred to as eye stroke, the main symptom is sudden, painless vision loss. If untreated, you may also experience blind spots, distorted vision, and peripheral vision loss. In addition to the previously mentioned causes, older adults may have higher risks for development. Your risks may also increase if you have glaucoma, or your blood is thicker and stickier than average.
Branch Retinal Artery Occlusion
If a blood clot develops in a single branch of an artery carrying blood to the retina, this can result in a branch retinal artery occlusion (BRAO). They can impact your central vision, as well as your ability to clearly see straight-ahead, direct images, as oxygenated blood is unable to reach the retina’s center (i.e., the macula). However, BRAOs can often be treated successfully; many patients who experience BRAOs are left with fair-to-good eyesight after timely treatment.
Central Retinal Vein Occlusion
When obstructions form in the main retinal vein, this is known as a central retinal vein occlusion (CRVO). A serious condition, CRVOs can damage veins’ structure, resulting in retinal bleeding and fluid leakage. A process known as neovascularization can then occur, in which your eyes develop abnormal, fragile veins to compensate. However, these new veins are more likely to easily bleed and leak, leading to symptoms such as floaters, hazy vision, issues with night vision, and difficulties with lighting changes.
Branch Retinal Vein Occlusion
Should a blockage develop in a smaller retinal vein, this is called a branch retinal vein occlusion (BRVO). BRVOs can cause vision loss if forming outside of the eye's center, and usually, it’s painless and sudden. BRVOs may develop with no symptoms, although some patients may experience floaters, loss of peripheral vision, distorted or blurry central vision, and bleeding in the vitreous.
Occlusion can impact your macula in the form of macular edema. With this serious condition, as fluids spill into the retina, the macula swells, forming a blister within the macula’s layers. It can make it difficult to see clearly, and as the swelling grows and thickens, you may notice central visual symptoms, like blurriness, distortion, and difficulty with “close-up” activities, such as reading. If untreated, chronic macular edema can result in unhealthy new blood vessel growth, irreversible macular damage, and permanent vision loss.
BRAO or CRAO are both considered medical emergencies requiring immediate medical treatment. Both conditions, if untreated, increase the risk of having a cerebral stroke. If not treated within 24 hours, CRAOs can also result in irreversible vision loss, but quick medical attention may allow you to preserve some vision.
Vein and Artery Occlusion Diagnostic Testing
Should you suspect a type of retinal occlusion, visit a retina specialist for a thorough exam to determine your eye’s health and function. In the process, the doctor will check your vision, measure your eye pressure, and take your blood pressure. Additionally, your eyes will likely be dilated, with special eye drops being applied to keep the pupil open, offering a closer, unobstructed look at your retina. You may also undergo such diagnostic tests as:
- Ophthalmoscopy, which enables the observation and assessment of any retinal damage. Patients with diabetes should have this test at least once a year.
- Fluorescein angiography, in which a retinal specialist injects a colored dye into the bloodstream, takes pictures, and analyzes the images for any signs of closed, broken, or leaking blood vessels.
- Optical coherence tomography (OCT), in which infrared light captures cross-sectional retinal images to determine if fluid has leaked into retinal tissue.
- Indocyanine green angiography, which involves an injected dye that lights up when exposed to infrared light, examines the retina’s deeper blood vessels.
Retinal Artery and Vein Occlusion Treatments
Currently, no cures exist for retinal artery or vein occlusions. If a mild occlusion is detected, the main protocol is typically to monitor the patients' eyes for any changes and proper management of any underlying conditions and risk factors, such as high blood pressure. If you require treatment, the goal will be to seal any leaking blood vessels.
One of the most common standard treatment procedures for many retinal conditions, including occlusive diseases, is anti-vascular endothelial growth factor (anti-VEGF) medications. Anti-VEGFs are injected directly into your affected eye’s vitreous using a very thin needle. Typically used for bleeding or macular edema, these intravitreal injections help stop abnormal blood vessel growth by targeting and stopping the responsible protein. Anti-VEGFs can effectively manage retinal vascular diseases and help preserve vision. Additional treatment may be needed, such as laser therapy to break down blood vessel damage or seal leaking vessels.
Advanced Care for Retinal Vein & Artery Occlusion in Illinois and Indiana
Illinois Retina Associates is a leading retina-only ophthalmology practice in the Midwest devoted to diagnosing and treating retinal disorders, including retinal vein and artery occlusions. When you or a loved one visit our retina centers, rest assured that our experienced retina specialists and surgeons will develop a personalized treatment plan to ensure your recovery. Contact one of our 12 convenient locations today to schedule a consultation.
