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What is the primary cause of retinal vein occlusions?
Which risk factor is most commonly associated with retinal vein occlusions in younger females?
What type of retinal vein occlusion is characterized by the occlusion of the main retinal vein?
Which of the following best describes the classification of retinal vein occlusions?
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In a branch retinal vein occlusion (BRVO), what typically causes the thrombosis?
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What is a common aetiology for retinal artery occlusions?
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Which condition is characterized by both non-ischaemic and ischaemic types?
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What differentiates non-ischaemic from ischaemic retinal vein occlusions?
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Which of the following is considered a significant warning sign of an impending stroke?
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What is the second most common sight-threatening vascular disorder?
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What primarily impedes blood flow in occlusive lesions?
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Which of the following conditions could mimic the presentation of retinal vascular occlusions?
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Which statement about retinal artery occlusions is incorrect?
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What is the primary cause of Central Retinal Artery Occlusion (CRAO)?
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Which type of embolus is characterized by a dull white color and often arises from carotid artery plaques?
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At what level does a Central Retinal Artery Occlusion (CRAO) occur?
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What is the mean age of patients who typically experience Central Retinal Artery Occlusion (CRAO)?
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What is the incidence rate of Central Retinal Artery Occlusion (CRAO) per year?
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What is a primary consequence of retinal thrombosis in Central Retinal Vein Occlusion?
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Which of the following is NOT a typical sign seen in Central Retinal Vein Occlusion?
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What leads to the production of VEGF in Central Retinal Vein Occlusion?
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Which complication is associated with abnormal new vessel growth in Central Retinal Vein Occlusion?
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What happens to capillaries during retinal ischaemia in Central Retinal Vein Occlusion?
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Which of the following classifications of Central Retinal Vein Occlusion indicates a better retinal blood supply?
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What contributes primarily to increased capillary permeability in macular oedema related to Central Retinal Vein Occlusion?
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What is a common finding on examination of a patient with Central Retinal Vein Occlusion?
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What is a common visual acuity measurement in Non-Ischaemic Central Retinal Vein Occlusions?
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What symptom is typically observed in Ischaemic Central Retinal Vein Occlusions?
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When should a patient with potential retinal vein occlusion be urgently referred to ophthalmology?
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What diagnostic tool has largely replaced Fluorescein Angiography (FFA) in assessing retinal non-perfusion?
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What condition may develop in 50% of patients with Ischaemic CRVO within 9-12 months?
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Which factor is NOT typically assessed by optometrists during the investigation of potential retinal vein occlusion?
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In which of the following conditions would you likely see new vessels at the disc, potentially leading to rubeosis irides?
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What complication is associated with new vessels everywhere in retinal vein occlusion?
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Study Notes
Retinal Vascular Occlusions
- Retinal artery occlusions are associated with an increased risk of cardiovascular events.
- The aetiology is an embolism from the carotid artery/aortic arch/heart breaking off and traveling to occlude either the central retinal artery or its branches.
- Retinal artery occlusions have a similar aetiology to an ischaemic stroke (85-87% of all strokes).
- Amaurosis Fugax is both a warning sign of an impending stroke and an opportunity to prevent it.
- Retinal vein occlusions are a major cause of sight loss - second most common sight threatening vascular disorder.
Types of Retinal Vein Occlusions
- Central retinal vein occlusions (CRVO)
- Branch retinal vein occlusions (BRVO)
- Hemi-retinal Vein occlusion (HRVO)
Classification of Retinal Vein Occlusions
- Ischaemic
- Non-Ischaemic
Risk Factors of Retinal Vein Occlusions
- Age (60- 70 years old)
- Diabetes
- Hypertension
- Hyperlipidaemia
- Blood disorders- high plasma viscosity, raised cell counts, and thrombophilic abnormalities.
- Systemic inflammatory disorders
- Oral contraceptive pill (most common underlying association when this occurs in younger females)
- Glaucoma
- Short axial length
- Retrobulbar compression
Aetiology of Retinal Vein Occlusions
- Thrombus (blood clot)
- Arteriosclerosis of the artery which compresses the underlying vein.
- Inflammation of the blood vessel.
- High Blood viscosity.
- Coagulation disorders
Pathogenesis of Retinal Vein Occlusions
- Atherosclerosis of the overlying artery causes compression of the underlying vein.
- Compression leads to an increase in venous and capillary pressure, hypoxia, and stagnation of blood flow.
- Loss of endothelial cell integrity and leakage of blood constituents.
- Capillaries shut down.
- Possible ischaemia.
Complications of RVO's
- Macular Oedema: Thrombosis leads to increased retinal capillary pressure which leads to increased permeability and leakage from capillaries resulting in macular oedema.
- Retinal Ischaemia: Non-perfusion of the capillaries causes retinal ischaemia. The production of VEGF and other cytokines, promote new vessel growth. These new vessels can grow on the iris and angle (resulting in neovascular glaucoma) or in the retina (resulting in vitreous haemorrhages and tractional retinal detachments).
Central Retinal Vein Occlusion
- Thrombosis of the Central Retinal Vein when it passes through the lamina cribrosa.
Signs of Central Retinal Vein Occlusion
- Extensive flame haemorrhages
- Blot and dot haemorrhages
- Disc oedema
- Tortuous dilated veins in all 4 quadrants
-
Other possibilities:
- Cotton wool spots
- Macular oedema
Non-Ischaemic Central Retinal Vein Occlusion Presentation
- VA ≥6/30
- Mild or absent RAPD
- Rare to have a visual field defect
- Mild tortuosity and dilation of central retinal vein
- Haemorrhages (dot/blot and flame)
- Mild optic disc oedema and hyperaemia
- Mild retinal and macular oedema
Ischaemic Central Retinal Vein Occlusion Presentation
- VA ≤ 6/60
- RAPD present
- Visual field defects present
- Severe retinal oedema
- Marked disc oedema
- Extensive haemorrhages
- Macular oedema
- 5DD of non perfusion
Branch Retinal Vein Occlusion
- Occlusion of a branch of the central retinal vein
- Often asymptomatic
- Common presentation:
- Visual field defect
- Haemorrhages (flame, dot, blot)
- Cotton wool spots
- Venous dilation
- Macular oedema
- Mostly non-ischaemic
Hemi-Retinal Vein Occlusion
- Occlusion of a major division of the central retinal vein
- Similar presentation to a branch retinal vein occlusion (BRVO), but often in a larger sector.
Central Retinal Artery Occlusion (CRAO)
- Occlusion of the central retinal artery at the level of the lamina cribrosa (or just behind).
- This occlusion results in a retinal hypoperfusion and thus retinal cellular damage and vision loss.
- This is an ophthalmic emergency.
CRAO Epidemiology
- Rare
- Incidence: 1-2 in 100,000 per year
- Mean age ~ 60-65 years
Cause of Central Retinal Artery Occlusion
- Embolus
- Types:
- Calcium- usually arise from cardiac valves, white single emboli, usually found closer to the optic nerve head
- Cholesterol (Hollenhorst plaque)- bright, refractile, yellow/orange plaques seen at bifurcations. Arise from ulcerated atheromas (plaques).
- Platelet-fibrin- Usually arise from atheromas (plaques) in the carotid arteries, dull white colour.
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Description
This quiz covers key concepts related to retinal vascular occlusions, including types, risk factors, and their connection to cardiovascular events. Understand the implications of central and branch retinal vein occlusions and their classifications. Test your knowledge to better grasp the pathophysiology and prevention strategies associated with these ocular conditions.
