Decoding the Veil: What is Retinal Vein Occlusion and How to Manage It

What is retinal vein occlusion (RVO)? This question marks the beginning of a journey through one of the most common retinal vascular diseases. Affecting a spectrum of individuals across various age groups, RVO is both a medical challenge and an inquiry into the delicate vascular network sustaining our sight.

What Exactly Is Retinal Vein Occlusion?

Retinal vein occlusion is the blockage of the retinal vein, which carries blood away from the retina. The retina, at the back of the eye, is where light is converted into nerve signals for the brain to interpret. When a vein within the retina becomes blocked, it can cause blood and other fluids to leak into the retina, leading to vision problems.

The Types of Retinal Vein Occlusions

There are mainly two types:

1. Central Retinal Vein Occlusion (CRVO): Occurs when the main retinal vein becomes blocked.
2. Branch Retinal Vein Occlusion (BRVO): Happens when one of the smaller branches of veins in the retina is blocked.

Causes of Retinal Vein Occlusion

The primary cause of retinal vein occlusion is a blood clot, which blocks the blood flow through the retinal veins. This can be due to several underlying conditions:

1. Blood Vessel Damage: Age and other health conditions can damage the walls of the blood vessels, making them more susceptible to clots.
2. Compression of the Vessels: Sometimes, the surrounding structures, such as the arteries, can compress a vein, leading to occlusion.
3. Increased Blood Viscosity: Conditions that increase the thickness of the blood can contribute to the formation of clots.

Risk Factors for Retinal Vein Occlusion

Understanding the risk factors is crucial since many of them are manageable. Here’s a list of the most commonly identified ones:

1. Age: RVO most commonly affects older adults, particularly those over the age of 60.
2. High Blood Pressure: Hypertension stands out as a prominent risk factor associated with RVO, making it a key contributor to this condition’s development. It can damage blood vessels over time, making them more prone to blockages.
3. Other Health Conditions: Diabetes, high cholesterol, and inflammatory conditions like rheumatoid arthritis increase the risk of RVO.
4. Glaucoma: Elevated pressure inside the eye can compress the retinal vein and lead to occlusion.
5. Blood Disorders: Conditions that affect blood clotting can increase the risk.
6. Smoking: This habit is associated with damage to the blood vessels and an increased risk of clotting.

Addressing the Risk Factors

Many of the risk factors for RVO are also risk factors for other serious health conditions, which means that addressing them can have widespread health benefits:

1. Maintain a Healthy Blood Pressure: Regular exercise, a balanced diet, and medication can control high blood pressure.
2. Manage Diabetes: Keeping blood sugar levels within the target range is crucial.
3. Lower Cholesterol: A healthy diet and medication can help reduce the risk of blood vessel damage.
4. Stop Smoking: Quitting smoking can significantly reduce the risk of RVO and improve overall vascular health.

The Importance of Regular Check-Ups

Since many risk factors for RVO are related to systemic health conditions, regular medical check-ups are essential. These should include:

• Eye Examinations: To detect early signs of vascular damage in the retina.
• Blood Pressure Monitoring: To prevent hypertension-related complications.
• Blood Tests: To monitor for conditions that affect blood viscosity and clotting.

Symptoms of Retinal Vein Occlusion

The symptoms of RVO often depend on the severity and type of the occlusion. Here are some of the symptoms that individuals may experience:

1. Visual Changes: These can include blurred or distorted vision, which may occur suddenly or develop over several hours or days.
2. Visual Loss: Some individuals may experience a sudden and painless loss of vision, particularly if the occlusion affects the central retinal vein.
3. Field of Vision Loss: With branch retinal vein occlusion, the loss of vision can occur in a specific part of the field of vision.
4. Floaters: These are dark spots or lines that float in the individual’s field of vision, caused by tiny clumps of blood or other material within the eye.

Diagnosing Retinal Vein Occlusion

The diagnosis of RVO is primarily based on a comprehensive eye examination and several specialised tests:

1. Ophthalmoscopy: An eye doctor uses a special instrument with a bright light to look at the back of the eye, including the retina and retinal blood vessels.
2. Optical Coherence Tomography (OCT): This non-invasive imaging test provides cross-sectional images of the retina and can show the presence of any swelling or fluid.
3. Fluorescein Angiography:  In this examination, a fluorescent dye is introduced into the bloodstream. The dye effectively illuminates the blood vessels located in the posterior section of the eye. This illumination facilitates the capturing of photographs, which in turn aids in the identification of potential blockages or leakage within those vessels.
4. Blood Tests: To identify or rule out systemic conditions such as diabetes, high cholesterol, or blood clotting disorders that could contribute to RVO.

What Happens After Diagnosis?

Following diagnosis, the ophthalmologist may:

1. Determine the Severity: The extent of the occlusion and its impact on the retina and vision is assessed to plan treatment.
2. Identify Underlying Conditions: If a systemic condition is suspected, the patient may be referred to other specialists for further evaluation and treatment.
3. Monitor Progression: Regular follow-up appointments are critical to monitor the condition’s progression and response to treatment.

Why Timely Diagnosis Matters

A prompt diagnosis is crucial for several reasons:

• Preventing Further Vision Loss: Early treatment can help preserve vision and, in some cases, improve it.
• Managing Complications: Conditions like macular edema and neovascular glaucoma can be sight-threatening complications of RVO. Early intervention can help manage these complications effectively.
• Addressing Systemic Health: Since RVO can be associated with systemic conditions, a diagnosis can prompt a more comprehensive health evaluation.

Medical Management

1. Monitoring: Regular follow-up examinations are crucial. These include checking visual acuity and intraocular pressure, along with retinal imaging.
2. Systemic Health Control: Management of systemic conditions like hypertension, diabetes, or hyperlipidemia is vital, often requiring collaboration with general physicians or specialists.
3. Medications:

• Anti-VEGF Injections: Medications such as ranibizumab, bevacizumab, or aflibercept may be used to decrease macular oedema and inhibit the growth of abnormal blood vessels by blocking vascular endothelial growth factor (VEGF).
• Corticosteroids: These may be injected or implanted in the eye to reduce macular oedema and inflammation.
• Anti-coagulants or Anti-platelets: In some cases, these may be prescribed to reduce the risk of further clot formation, although their use is dependent on the individual’s overall health profile and is somewhat controversial in the context of RVO.

Laser Therapy

1. Laser Photocoagulation: This treatment can seal leaking vessels in the retina and is particularly useful in cases of BRVO.
2. Panretinal Photocoagulation: For cases where abnormal new blood vessels (neovascularisation) have developed, this treatment can help prevent further complications like vitreous haemorrhage or neovascular glaucoma.

Surgical Options

Surgery is not the first line of treatment but may be considered in certain circumstances:

• Vitrectomy: This procedure might be recommended if there is vitreous haemorrhage or if the macula is being tugged on by vitreoretinal traction, contributing to macular edema.

Lifestyle Adjustments

1. Diet and Exercise: A heart-healthy diet and regular exercise can improve overall vascular health.
2. Smoking Cessation: As smoking is a significant risk factor for RVO, quitting is strongly advised.
3. Eye Protection: It’s advisable to protect the eyes from potential injury, which could exacerbate the condition.

Vision Rehabilitation

For those who have experienced substantial vision impairment:

• Low Vision Aids: Devices like magnifiers can help make the most of remaining vision.
• Vision Rehabilitation Services: These invaluable services assist individuals in adapting to vision changes, empowering them to maintain their independence and autonomy with confidence.

Addressing Complications

1. Macular Oedema: It’s a common complication that can lead to vision loss and is often managed with anti-VEGF injections or corticosteroids.
2. Neovascular Glaucoma: If new blood vessels grow on the iris and obstruct fluid drainage, leading to high intraocular pressure, this may require laser therapy or surgery.

Frequently Asked Questions About Retinal Vein Occlusion

What causes retinal vein occlusion?

RVO occurs when the veins responsible for carrying blood away from the retina become obstructed, often as a result of a blood clot. This blockage can be associated with conditions that affect blood flow, including high blood pressure, diabetes, glaucoma, and blood clotting disorders.

Are there different types of RVO?

Yes, there are two main types: central retinal vein occlusion (CRVO) and branch retinal vein occlusion (BRVO). CRVO affects the main retinal vein, whereas BRVO affects its smaller branches.

What are the symptoms of RVO?

Symptoms include a sudden or gradual decrease in vision, seeing floaters, blurry vision, and sometimes pain if there is associated elevated eye pressure or inflammation.

How is RVO diagnosed?

Diagnosis typically involves a thorough eye examination, including visual acuity tests, retinal imaging with optical coherence tomography (OCT), and fluorescein angiography to assess the health of the retinal blood vessels.

Can RVO lead to permanent vision loss?

Yes, RVO can lead to permanent vision loss, especially if not treated promptly. The degree of vision loss varies depending on the severity and location of the occlusion, as well as the development of complications such as macular oedema.

What are the treatment options for RVO?

Treatment options include anti-VEGF injections to reduce macular oedema, laser therapy to seal or shrink abnormal blood vessels or to reduce the risk of neovascularisation, and corticosteroids to reduce inflammation. Lifestyle changes and controlling systemic health conditions are also important.

Is there any way to prevent RVO?

While not all cases are preventable, managing risk factors like high blood pressure, diabetes, and cholesterol can decrease the risk. Regular eye exams are also critical for early detection and prevention of complications.

What is macular oedema, and how is it related to RVO?

Macular oedema is the swelling or thickening of the macula, which is the part of the retina responsible for detailed central vision. It is a common complication of RVO that can lead to significant vision loss.

Can RVO occur in both eyes?

RVO typically affects one eye at a time, but it is possible for it to occur in both eyes, either simultaneously or at different times.

Are there any new treatments being developed for RVO?

Research into RVO is ongoing, with clinical trials for new drugs and therapeutic approaches being conducted. Treatments that target the underlying causes of vascular blockages, improve blood flow, and address retinal health are in various stages of development.

Conclusion

Retinal vein occlusions pose a significant threat to vision, but with the right knowledge and proactive management, individuals can maintain their eyesight and quality of life. It’s essential to be informed, prepared, and in regular consultation with eye care professionals.

Contact us at (03) 9070 5753 today if you have any questions about RVO or want to discuss more information on how to keep your eyes healthy. We’re here to help!

Note: Any surgical or invasive procedure carries risks. Before proceeding, you should seek a second opinion from an appropriately qualified health practitioner.

References 

1. https://my.clevelandclinic.org/health/diseases/14206-retinal-vein-occlusion-rvo
2. https://www.hopkinsmedicine.org/health/conditions-and-diseases/central-retinal-artery-occlusion

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