Retinal Vein Occlusions & Artery Occlusions
Like any part of the eye, your retina requires a steady supply of blood and oxygen. However, if a retinal artery or vein occlusion develops, this essential oxygenated blood cannot reach the retina. You may experience such symptoms as eye inflammation and swelling, and eventually, unhealthy new blood vessel growth and permanent vision loss may occur.
While RAOs and RVOs are incurable, their underlying conditions and risk factors can be managed. If treatment is needed, injectable medications and laser therapy may seal leaking blood vessels and break down blood vessel damage. While these conditions are considered medical emergencies, immediate treatment may enable you to preserve some vision. At Retina Consultants of Charleston, we’re experienced in treating retinal artery occlusions and retinal vein occlusions.
How Retinal Artery Occlusions And Vein Occlusions Develop
Within our bodies, blood flow is constant. The arteries transport blood from the heart throughout the body, while the veins return all of the tissues’ blood to the heart. Oxygenated blood is delivered by the retinal vascular system. Its main parts are the central retinal artery (extending from the neck’s internal carotid artery) and the central retinal vein. The arteries and veins, which have thin walls, branch off from the optic nerve and travel together within the retina, becoming smaller and binding to each other.
If you have hypertension (high blood pressure), your arterial walls can thicken and harden over time, a condition called atherosclerosis. As your adjacent veins may be compressed, blood flow slows and stops, causing ruptures in the capillaries, the smallest and most numerous blood vessels. Pressure can then build, leading to retinal bleeding and inflammation.
If you have significant retinal leakage, this can cause swelling in the macula, the center of the retina. Known as macular edema, this condition may be serious, as the macula controls your sharp, straight-ahead vision, enabling close-up activities like reading and driving. As your retinal blood loss worsens, you may experience unhealthy new blood vessel growth or even permanent vision loss.
Understanding the Various Retinal Occlusion Types
With retinal artery and vein occlusions, there are various types. These depend on the specific artery or vein and its location in the retina.
With a branch retinal artery occlusion (BRAO), a blood clot develops in a branch that stems from the central retinal artery. If oxygenated blood is unable to reach the macula, you may lose central vision.
A central retinal artery occlusion (CRAO), also known as eye stroke, is a serious condition. While its main symptom is sudden, painless vision loss, there may be blind spots, distorted vision, and peripheral vision loss. CRAOs may prevent retinal blood flow and cause severe vision loss.
A branch retinal vein occlusion (BRVO) is a blockage in a smaller retinal vein. Generally, if BRVOs occur outside of the eye's center, they cause painless, sudden vision loss. They can cause blood and other fluids to leak into the retina. While BRVOs may have no symptoms, you may experience eye floaters, loss of peripheral vision, and distorted or blurry central vision. You may also have bleeding in the vitreous, the clear, jelly-like gel that makes up most of the eye’s volume.
Should a blockage develop in the main retinal vein, this is known as a central retinal vein occlusion (CRVO). A serious condition, CRVOs can cause structural damage to the veins, leading to retinal bleeding and fluid leakage. To compensate, your eyes develop new, fragile veins, but they’re prone to bleeding and leaking and may cause floaters.
Are Retinal Occlusions Considered Medical Emergencies?
Both BRAOs and CRAOs should be treated as medical emergencies, as they may indicate an increased risk of a cerebral stroke. CRAOs can lead to irreversible vision loss if not treated within 24 hours. The sooner you treat CRAOs, the better your chances of preserving some vision. CRAOs are also considered medical emergencies. Immediate medical treatment is required, as this may prevent irreversible vision loss.
Risk Factors For Artery And Vein Occlusions
Studies show that for retinal artery and vein occlusions, patients are typically in their 60s, and men tend to develop them more than women. Assuming blood flow is restored, occlusions usually last for only a few seconds or minutes. In most cases, occlusions target a single eye, with both eyes being affected in only 1-2% of cases. Among the common risk factors are:
- Being overweight or obese; having an increased body mass index (BMI)
- Cardiovascular disease
- High blood pressure, especially among senior patients
- High cholesterol
- Narrowing of the carotid artery
- For younger BRVO patients, there may be an abnormal blood clotting tendency
- Female CRAO patients may have blood that is thicker and stickier than normal; this may be associated with birth control pill use.
Diagnosis of Retinal Vascular Occlusions
If you suspect a retinal occlusion, your retina specialist will conduct a thorough eye exam. The exam’s purpose is to assess your eye’s health and function, and it will include the doctor checking your vision, measuring your eye pressure, and taking your blood pressure.
For mild artery or vein occlusions, the retinal specialist will usually just monitor your eyes. You can expect your eyes to be dilated, which involves special eye drops being applied to keep the pupil open, allowing a closer, unobstructed look at your retina. In addition, there may be such diagnostic tests as:
Ophthalmoscopy involves a retinal specialist using an ophthalmoscope, an instrument that enables the observation and assessment of any retinal damage. If you have diabetes, it’s recommended that you get this test at least once a year.
Fluorescein angiography is a test in which the eye’s blood vessels are highlighted. The retinal specialist injects a colored dye into the bloodstream, takes pictures, and analyzes the images for signs of closed, broken, or leaking blood vessels.
Optical coherence tomography (OCT) involves infrared light being used to capture cross-sectional retinal images to determine if fluid has leaked into the retinal tissue.
Indocyanine green angiography employs an injected dye that lights up when exposed to infrared light. However, with this test, the retina’s deeper blood vessels are examined.
Retinal Artery And Vein Occlusion Treatments
No cures are available for retinal artery or vein occlusions. In most cases, your ophthalmologist will recommend that you properly manage any underlying conditions and risk factors contributing to these conditions, such as high blood pressure or cardiovascular disease. But if you do require treatment for an occlusion, sealing any leaking blood vessels is the main goal.
For any bleeding or macular edema development, you may be given medications known as anti-vascular endothelial growth factor (anti-VEGF) medications. They help stop the growth of abnormal blood vessels by inhibiting the responsible protein. Anti-VEGFs are injected directly into your affected eye’s vitreous, using a very thin needle. They are effective in managing retinal vascular diseases and help maintain vision.
You may also require additional treatment, focal laser therapy, or surgery (photocoagulation). With this procedure, a high-energy laser beam is used to break down blood vessel damage or seal leaking blood vessels.
What Is The Prognosis For Retinal Occlusions?
Generally, retinal occlusion patients do well. If you only have macular edema, you will probably receive injections, and while effective, you will have to continue them for several years until the blood vessels have repaired themselves. But should macular blood vessel loss develop, permanent vision loss may occur.
Schedule a Consultation for Injections in South Carolina
Retinal artery occlusions and retinal vein occlusions can cause extensive damage to your eyes. However, the vitreoretinal surgeons of Retina Consultants of Charleston are experienced in treating these conditions. If you suspect an occlusion or you have questions, we encourage you to contact us for an appointment.