[1] Retinal Venous Occlusion Flashcards
What is retinal venous occlusion?
An interruption of the normal venous drainage from the retinal tissue
What can become occluded in retinal venous occlusion?
- Central retinal vein
- Branch of the central retinal vein
What are the two possible (and sometimes overlapping) types of central retinal venous occlusion?
- Non-ischaemic CRVO
- Ischaemic CRVO
What is non-ischaemic CRVO?
A milder form of the disease that may resolve fully with a good visual outcome
What percentage of CRVO’s are non-ischaemic in nature?
75%
What is the risk of non-ischaemic central retinal venous occlusion?
It can progress to become ischaemic type
What can occur as a result of ischaemic central retinal venous occlusion?
Patient may be left with neovascular glaucoma and painful eye with severe visual impairment
Is central retinal venous occlusion or branched retinal venous occlusion more common and by how much?
Branched retinal venous occlusion is 3 times as common as central
How are branched retinal venous occlusions further classified?
Whether the affected vein is a major, minor or peripheral vessel
What is it called when (uncommonly) a vein that drains half the retina is affected?
Hemiretinal vein occlusion
What is the most common cause of retinal venous occlusion?
Thrombus formation
What are some less common causes of retinal venous occlusion?
- Disease of the vessel wall
- External compression of the vein
What happens to the blood as a result of retinal venous occlusion?
There is a backlog and stagnation which combines with hypoxia to result in extravasation of constituents causing further compression and a vicious circle is produced
What is stimulated if there is ischaemic damage to the retina?
Increased production of vascular endothelial growth factor (VEGF)
What does VEGF cause?
Neovascularisation
What can neovascularisation lead to?
- Haemorrhage
- Neovascular glaucoma
Why can neovascularisation lead to haemorrhage?
As the new vessels are of poor quality
What is neovascular glaucoma?
Where new blood vessels grow into the aqueous drainage system and cause blockage
What are the risk factors for retinal venous occlusion?
- Hypertension
- DM
- Hyperlipidaemia
- Smoking
- Obesity
- Raised IOP
- Inflammatory disease e.g. sarcoidosis
- Hyperviscosity states e.g. myeloma
- Thrombophilic disease
What does presentation of branch retinal venous occlusion largely depend upon?
Amount of compromise to the macular drainage
What does the extent of the effect on macular drainage influence?
The effect on visual acuity
What is the most common presentation of branch retinal venous occlusion?
- Unilateral, painless blurred vision
- Metamorphopsia
- Field defect
What is metamorphopsia?
Image distortion
What direction is the field defect typically in branch retinal venous occlusion?
Altitudinal
When may branch retinal venous occlusion be asymptomatic?
In peripheral vein disease
What will fundoscopy show in branch retinal venous occlusion?
- Vascular dilatation and tortuosity of affected vessels
- Associated haemorrhage of affected area only
What is the typical presentation of a patient with central retinal venous occlusion?
Sudden unilateral painless loss of vision or blurring
When do the visual symptoms of central retinal venous occlusion often start?
Upon waking
What can be seen on examination in non-ischaemic central retinal venous occlusion?
- Mild or absent afferent pupillary defect
- Widespread dot-blot and flame haemorrhages
- Some disc oedema
What can be seen on examination in ischaemic central retinal venous occlusion?
- Severe visual impairment
- Marked RAPD
- Fundus looks smaller to non-ischaemic picture, disc oedema is more severe
- Haemorrhages in fundus in blood-storm pattern
- Cotton wool spots
What can be associated with ischaemic central retinal venous occlusion and can sometimes be seen on examination?
Retinal detachment
What are investigations used for in retinal venous occlusion?
To identify underlying system problems
What test can be used in retinal venous occlusion to identify any underlying causes?
- BP
- Blood glucose and lipids
- FBC and ESR
- Plasma protein electrophoresis
- ECG
What tests may be needed in atypical cases e.g. retinal venous occlusion in a younger patient?
- Thrombophilia screen
- CRP
- Auto-antibodies
What investigations are made for retinal venous occlusion in the eye clinic?
- Fluorescein angiogram
- Measurement of IOP
- Optical coherence tomography
What can fluorescein angiogram be used for in retinal venous occlusion?
- Confirm diagnosis
- Assess for complications
- Evaluate retinal capillary nonperfusion, neovascularisation and oedema
What can OCT be used for in retinal venous occlusion?
Measure the retina and detect macular oedema
What are the differentials for retinal venous occlusion?
- Diabetic retinopathy
- Other causes of sudden unilateral visual loss
- Other causes of macular oedema
What are some other causes of sudden unilateral visual loss (other than retinal venous occlusion)?
- Retinal detachment
- Retinal artery occlusion
How is uncomplicated branch retinal venous occlusion managed?
With observation and management of underlying conditions
What underlying conditions should be managed in branch retinal venous occlusion?
- Hypertension
- Hyperlipidaemia
- DM
What should patients with uncomplicated branch retinal venous occlusion be monitored for?
- Macular oedema
- Neovascularisation
If macular oedema develops in branch retinal venous occlusion, how should it be managed first line?
Intravitreal VEGF inhibitors
If macular oedema persists in branch retinal venous occlusion despite several monthly injections of VEGF inhibitors what should be used?
Intravitreal corticosteroid (dexamethasone) as well as anti-VEGF therapy
If 3 months of intravitreal treatment is not effective at reducing macular oedema, what can be used?
Grid-pattern laser photo-coagulation
Are there treatments for central retinal venous occlusion?
Not really, just manage risk factors and complications
What is the aim if neovascular glaucoma occurs due to central retinal venous occlusion?
Keep the eye pain free
What is the management of uncomplicated central retinal venous occlusion?
Manage underlying conditions and observe
Which patients with central retinal venous occlusion should receive more regular observation?
Those with ischaemic central retinal venous occlusion
How should macular oedema be managed in central retinal venous occlusion?
As in branch retinal venous occlusion
What is the treatment for neovascular glaucoma in central retinal vein occlusion?
- Pan-retinal photocoagulation
- Manage IOP
How can IOP be managed in neovascular glaucoma?
- Ophthalmic β-blockers
- Carbonic anhydrase inhibitors
What are the complications of branch retinal venous occlusion?
Similar to retinal artery occlusion
What are the complications of central retinal venous occlusion?
- Neovascularisation and secondary glaucoma or vitreous haemorrhage
- Macular oedem
- Lamellar or full thickness macular hole
- Permanent macular degeneration
- Optic atrophy
What will most patients who have had long-term macular oedema have as a result?
Reduced central vision
