Retinal Vein Occlusions

Retinal Artery and Vein Occlusion Care in Chattanooga, Knoxville, and the Tri-Cities Region

The retinal vascular system continuously supplies nourishing blood to the retina through arteries while removing waste through veins. Blockages, or occlusions, caused by blood clots or fatty deposits, can occur suddenly, leading to what’s known as retinal artery occlusions (RAO) and retinal vein occlusions (RVO). RAOs and RVOs are medical emergencies requiring rapid treatment to prevent irreversible vision loss. At Southeastern Retina Associates, we promptly diagnose and treat retinal vascular occlusions at their onset, ensuring more effective treatment and preserving your vision.

What are Retinal Vascular Occlusions?

Within the retinal vascular system, blood vessels called arteries bring oxygen-rich blood from the heart and disburse it throughout the body, including to the retina and adjacent parts, like the choroid. Meanwhile, veins have the role of returning oxygen-depleted blood and related waste materials back to the heart, allowing the process to begin all over again. The retinal vascular system consists of two key components – the central retinal vein and the central retinal artery, both emanating from the neck’s internal carotid artery.

These blood vessels stretch from the optic nerve, reducing in size and converging closer together as they get closer to the retina. When occlusions occur, it impacts how blood flow functions, sometimes delaying it or stopping it completely. This can lead to breaks in small blood vessels known as capillaries; as pressure increases, retinal bleeding and inflammation can occur.

To compensate for the damaged blood vessels and disrupted blood flow, the eyes sometimes undergo a process called neovascularization, where unusual blood vessels form. Unfortunately, these new blood vessels harm the eye’s ability to function properly; they are exceedingly delicate and break easily, often leaking fluid and blood into the retina. Neovascularization can cause a wide range of complications, including macular edema (swelling of the retina’s center), vitreous hemorrhage, and retinal detachment.

Types and Symptoms of Retinal Vascular Occlusions

Different types of retinal vascular occlusions can develop, depending on their specific location within the retinal artery, vein, or their respective branches.

Central Retinal Artery Occlusion (CRAO)

Targeting the central retinal artery, a CRAO is also called an “eye stroke.” CRAOs are a significant health threat, as it is capable of severing the retina’s oxygen-rich blood supply. They also have a strong correlation with cerebral strokes.

The primary symptom of CRAO is spontaneous, yet painless loss of vision. Other signs include blind spots, visual distortions, and a permanent loss of peripheral vision.

Branch Retinal Artery Occlusion (BRAO)

BRAOs are generated in the vascular branches growing from the central retinal artery. BRAOs can cut off the blood supply going to the macula. BRAO may have no symptoms, provided the affected area is relatively small or is not located in the eye’s center.

Central Retinal Vein Occlusion (CRVO)

CRVOs impact the central retinal vein. You may develop a nonischemic CRVO, a mild form in which retinal blood vessels leak, or an ischemic CRVO, a severe type that reduces or stops blood flow. Although CRVOs can be mild, if the occlusion worsens, the veins can experience structural damage, causing neovascularization.

Although blurry vision is common with CRVO, milder stages may have no symptoms. As they grow in severity, pain or redness can develop in your affected eye. With CRVOs, you must quickly alert your ophthalmologist if you have any symptoms, even mild. The earlier diagnosed and treated, the better your chances of lowering vision loss.

Branch Retinal Vein Occlusion (BRVO)

When occlusions affect smaller veins growing off of the central retinal vein, these are branch retinal vein occlusions (BRVO). While these occlusions may present with no symptoms, many patients can experience eye floaters, peripheral vision loss, and central vision distortions or blurriness. Additionally, BRVOs can lead to bleeding in the vitreous.

Retinal Vascular Occlusion Risk Factors

Several risk factors can contribute to the development of retinal vascular occlusions. These include:

• Age
• Hypertension
• Diabetes
• Smoking
• High cholesterol
• Cardiovascular diseases, such as atherosclerosis
• Glaucoma
• Blood clotting disorders
• Family history
• Obesity
• Ocular conditions, such as macular edema, retinal vein tortuosity, and other retinal vascular abnormalities

It's important to note that these factors often interact, and an individual with multiple risk factors may have an increased overall risk of developing retinal vascular occlusions. Regular eye exams and monitoring of systemic health conditions can help in the early detection and management of risk factors, potentially reducing the risk of retinal vascular occlusion. If you have concerns about your eye health or risk factors, it's advisable to consult with an eye care professional or a healthcare provider.

Diagnosing Retinal Artery and Vein Occlusions

Retinal vascular occlusions are medical emergencies, particularly BRAOs or CRAOs, which may indicate a greater likelihood of cerebral stroke development. As such, if you suspect this threat, you must get treatment in less than 24 hours or you may be at risk for permanent vision loss. Earlier treatment boosts your chances of preserving some vision. Your doctor may refer you to a retinal specialist, a physician with specialized education and training in diagnosing and treating vitreoretinal disorders. They’ll coordinate with your ophthalmologist, ensuring an effective patient experience.

You’ll undergo a comprehensive eye exam to analyze your eye’s health and function. A variety of diagnostic tests may be performed, including ophthalmoscopy, fluorescein angiography, and optical coherence tomography (OCT).

Treatment for Retinal Artery and Vein Occlusions

The treatment for retinal vascular occlusions (RVO) aims to manage the underlying causes, prevent complications, and, in some cases, improve vision. The specific approach depends on the type and severity of the occlusion. Common treatment strategies include:

• Observation and monitoring, especially for BRVO with mild symptoms
• Intravitreal injections of anti-vascular endothelial growth factor (VEGF) drugs, such as Lucentis and Eylea
• Intravitreal steroid injections
• Retinal laser photocoagulation to seal leaking blood vessels, reduce edema, or treat neovascularization
• Vitrectomy for severe complications, such as vitreous hemorrhage or retinal detachment
• Management of underlying conditions

Retinal Artery and Vein Occlusions FAQs

• Are retinal artery and vein occlusions ommon?

  Retinal vascular occlusions are among the main causes of sudden vision loss. For CRAOs, 1-2 cases out of every 100,000 people are diagnosed each year. BRAOs represent about 38% of all retinal artery occlusions. Retinal vein occlusions are also common, ranking as the second-most common disorder affecting your retina.

• Why is a central retinal artery occlusion called “eye stroke”?

  CRAOs are sometimes colloquially referred to as "eye strokes" due to the similarity in the concept of sudden, severe vision loss caused by an interruption of blood flow, much like a stroke affecting the brain. In a CRAO, there is a blockage in the central retinal artery, the blood vessel that supplies the retina with oxygen and nutrients. This blockage can lead to a rapid and profound loss of vision in the affected eye. While the term "eye stroke" is not a medical classification, it is used to convey the seriousness and sudden onset of vision impairment associated with CRAOs.

• What is the prognosis for retinal artery and vein occlusions?

  Depending on the occlusion’s location and any complications, visual outlooks can vary. You may experience gradually improved vision, although permanent vision damage can still develop. In general, retinal vein occlusions have a better prognosis than artery occlusions.

  However, individual outcomes can vary widely, and the prognosis for both conditions depends on factors such as the extent of the occlusion, the speed of intervention, and the presence of underlying systemic conditions. Individuals with retinal vascular occlusions must seek prompt medical attention for an accurate diagnosis and appropriate management to optimize the chances of preserving vision. Regular follow-up with an eye care professional is also crucial for monitoring and managing potential complications.