11/14/24, 10\:46 AM Retinal Vein Occlusion

Retinal Vein Occlusion

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Retinal vein occlusion\: thrombus formation in retinal veins obstructing venous drainage; second most common cause of
blindness due to retinal vascular disease; prevalence 0.52%, mostly in patients >65.
Classi
Branch retinal vein occlusion\: obstruction of one of four retinal veins; bilateral in 5-10% of cases.
Central retinal vein occlusion\: obstruction of the main retinal vein draining all retinal capillaries; classi
(poorer prognosis) or non-ischaemic.
Pathophysiology\: atherosclerotic thickening of retinal arteries compresses retinal veins, leading to endothelial damage,
turbulent blood
Risk factors\: age, atherosclerosis (hyperlipidaemia, hypertension, diabetes), open-angle glaucoma, in
conditions (sarcoidosis, Lyme disease), hypercoagulable states (smoking, OCP, pregnancy, malignancy, sickle cell disease),
myeloproliferative disorders, systemic vasculitis (Behcet’s, polyarteritis nodosa).
Symptoms\: sudden, painless unilateral visual loss (gradual onset in BRVO), partial visual
(distorted vision).
Clinical examination\:
Visual\: reduced visual acuity, relative a
Ophthalmoscopy\: dot/blot haemorrhages, vascular dilatation, tortuosity, macular oedema, cotton wool spots, optic disc
swelling, neovascularisation, vitreous haemorrhage, raised intraocular pressure.
Investigations\:
Bedside\: blood pressure measurement.
Laboratory\: FBC, glucose, ESR, LFTs, TFTs, CRP, serum ACE, serum protein electrophoresis, thrombophilia screen.
Ophthalmic imaging\: fundal photography, optical coherence tomography, fundus
Other imaging\: chest X-ray (rarely required).
Management\:
Systemic\: optimise systemic risk factors (e.g., control blood pressure and glucose).
Ophthalmic\: anti-VEGF agents, intravitreal steroids, macular laser therapy for macular oedema; pan-retinal
photocoagulation for neovascular complications.
Follow-up\: initially every 4-6 weeks, depending on disease severity.
Complications\: macula oedema, neovascularisation, vitreous haemorrhage, secondary glaucoma.
Prognosis\: 50% of non-ischaemic RVO cases recover visual acuity; 50-60% of untreated BRVO cases have visual acuity
≤6/12; poorer prognosis with ischaemic RVO and complications.
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A comprehensive topic overview

Introduction

Retinal vein occlusion (RVO) occurs when a thrombus forms in the retinal veins and obstructs the venous drainage from
the retina. The central retinal vein runs through the optic nerve and is responsible for draining retinal capillaries.
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RVO is the second most common cause of blindness due to retinal vascular disease. Over 50% of cases occur in patients
older than 65.
The overall prevalence of RVO is 0.52%.

Aetiology

Classi

RVO can be classi
1
Branch retinal vein occlusion (BRVO)\: due to obstruction of one of the four retinal veins
Central retinal vein occlusion (CRVO)\: due to obstruction of the main retinal vein, which is responsible for draining all
retinal capillaries
RVO typically occurs unilaterally, however, branch RVO occurs bilaterally in 5-10% of cases.
RVO can also be classi
Ischaemic changes are associated with poorer prognosis due to retinal non-perfusion, capillary closure and retinal hypoxia,
which increases the risk of neovascularisation.

Pathophysiology

In CRVO, atherosclerotic thickening of the central retinal artery leads to compression of the central retinal vein at an
arteriovenous crossover point in the lamina cribosa, resulting in endothelial damage, turbulent blood
formation.
In BRVO, arteriosclerotic changes of a branch retinal arteriole similarly compress and occlude a branched venule.
Both circumstances can lead to retinal tissue ischaemia, infarction, vessel leakage and neovascularisation.

Risk factors

The exact cause of RVO is unknown, however, there are several associated risk factors including\:
1,3
Age
Atherosclerosis\: hyperlipidaemia, hypertension and diabetes
Open-angle glaucoma
In
Hypercoagulable states\: smoking, oral contraceptive pill, pregnancy, malignancy, sickle cell disease
Myeloproliferative disorders
Systemic vasculitis\: Behcet’s disease, polyarteritis nodosa

Clinical features

History

The main symptom is sudden, painless unilateral visual loss. The onset of visual loss is more gradual than with a retinal
artery occlusion.
BRVO typically presents with partial visual
is spared.
It is important to assess for relevant risk factors such as\:
Hypertension
Diabetes
Oral contraceptive pill
Smoking
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Family history of vascular disease

Clinical examination

On examination of the eyes and vision, clinical features of a retinal vein occlusion may include\:
Reduced visual acuity\: signi
Relative a
Visual
Clinical ophthalmoscopy may include\:
General\: dot/blot haemorrhages, vascular dilatation and tortuosity of retinal veins (distribution of these dictates BRVO or
CRVO with one, or four vein territories respectively involved)
Macular oedema\: hard exudate
Evidence of ischaemia\: haemorrhages, cotton wool spots, optic disc swelling
Neovascular complications\: neovascularisation and iris rubeosis, vitreous haemorrhage
Raised intraocular pressure is suggestive of neovascular glaucoma.
In BRVO, signs are con
Figure 1. Branch retinal vein occlusion of the superotemporal branch vein in the right eye. Fundus photograph showing widespread
haemorrhages and axonal congestion (cotton wool spots; white circles) upstream of the venous occlusion.
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Figure 2. Non-ischaemic central retinal vein occlusion.
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Figure 3. Ischaemic central retinal vein occlusion.
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Di

See the Geeky Medics guide to sudden painless loss of vision for other causes of sudden visual loss.

Investigations

Retinal vein occlusion is a clinical diagnosis, supported by ophthalmoscopy.

Bedside investigations

Relevant bedside investigations include\:
Blood pressure\: hypertension is commonly associated with BRVO

Laboratory investigations

Relevant laboratory investigations include\:
Full blood count\: to screen for haematological malignancy
Glucose\: to assess for diabetes
ESR\: to look for in
Investigations to screen for less common causes of retinal vein occlusion include\:
Liver function tests
Thyroid function tests
CRP
Serum angiotensin-converting enzyme
Serum protein electrophoresis
Thrombophilia screen\: SLE auto-antibody, antiphospholipid autoantibody

Ophthalmic imaging

Relevant ophthalmic imaging investigations include\:
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Fundal photography\: typically wide-
Optical coherence tomography\: for assessment of macula oedema
Fundus
ischaemic and need for laser treatment

Imaging

Other relevant imaging investigations may include\:
Chest X-ray\: to exclude tumours, vasculitis (rarely required)

Management

Patients with a suspected retinal vein occlusion should be immediately referred to ophthalmology for assessment.

Systemic and general management

A diagnosis of retinal vein occlusion should be explained to the patient with appropriate information and support.
It is fundamental to identify and optimise systemic risk factors to minimise the risk of vein occlusion to the other eye (e.g.
control of blood pressure and blood glucose).

De

There is currently no treatment to reverse the pathology associated with retinal vein occlusion.
Management focuses on treating and preventing complications to control symptoms and prevent further visual loss.
Treatment for macular oedema may include\:
3
Anti-VEGF agents (ranibizumab, a
Intravitreal steroid implant (dexamethasone)\: may also help control oedema and blood leakage
Macular laser therapy\: less common
Treatment for neovascular complications may include pan-retinal photocoagulation (or sectoral in BRVO). This can restore
some central vision by resolving macular oedema and prevent further neovascularisation

Follow-up

Ophthalmology follow-up is dependent on disease severity, but can initially be as frequent as every 4-6 weeks.
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Complications

Patients with retinal vein occlusion are at risk of macula oedema, neovascularisation and vitreous haemorrhage (may
require vitrectomy and pan-retinal photocoagulation), alongside secondary glaucoma.
1,3,7

Prognosis

In non-ischaemic RVO, visual acuity can restore or closely recover in about 50% of patients. Around 50–60% of untreated
BRVO cases have visual acuity equal to 6/12 or worse.
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Ischaemic presentation and occlusion complications can reduce this prognosis signi
occurs in about 5% of cases.

References

th
Baldwin A, Goumalatsou C, Hjelde N, Myers G. O x f o r d H a n d b o o k o f C l i n i c a l S p e c i a l i t i e s 10 Oxford\: Oxford University Press;
2016.
Rogers S et al. The prevalence of retinal vein occlusion\: pooled data from population studies from the United States,
Europe, Asia, and Australia. Ophthalmology 2010;117\:313–319.
https\://app.geekymedics.com/notebook/2648/ 5/611/14/24, 10\:46 AM Retinal Vein Occlusion
Bowling B. K a n s k i’ s C l i n i c a l O p h t h a l m o l o g y \: A s y s t e m a t i c a p p r o a c h t h
8 E d ; Elsevier; 2016.
EyeWiki. BRVO. License\: [CC-BY-NC]
EyeWiki. NI CRVO. License\: [CC-BY-NC]
EyeWiki. Colour ischaemia. License\: [CC-BY-NC]
MoorLINK]
Sivaprasad S, Amoaku WM, Hykin P et al. The Royal College of Ophthalmologists Guidelines on retinal vein occlusions\:
executive summary. Eye 2015;29\:1633–1638.

Reviewer

Dr Ashley Simpson
ST4 Ophthalmology

Related notes

Acute Angle-Closure Glaucoma
Age-related Macular Degeneration (ARMD)
Amblyopia
Ametropia
Anisocoria

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Contents

Introduction
Aetiology
Risk factors
Clinical features
Di
Investigations
Management
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