Retinal Vein Occlusion Flashcards
What is retinal vein occlusion (RVO)?
Retinal vein occlusion (RVO) is an interruption of the normal venous drainage from the retinal tissue. Either the central vein (CRVO) or one of its branches (BRVO) can become occluded.
How many branches form the retinal vein? What imact does this have on RVO?
There are four branched veins that come together to form the central retinal vein. Blockage of one of the branch veins causes problems in the area drained by that branch whereas blockage in the central vein causes problems with the whole retina.
Briefly describe the pathophysiology of RVO
Blockage of a retinal vein causes pooling of blood in the retina. This results in leakage of fluid and blood causing macular oedema and retinal haemorrhages. This results in damage to the tissue in the retina and loss of vision. It also leads to the release of VEGF, which stimulates the development of new blood vessels (neovascularisation).
What are the risk factors for RVO?
- Hypertension
- High cholesterol
- Diabetes
- Smoking
- Glaucoma
- Systemic inflammatory conditions such as systemic lupus erythematosus
What are the clinical features of RVO?
Blockage of one of these retinal veins causes sudden painless loss of vision.
How does RVO present on fundoscopy?
Fundoscopy examination is diagnostic of retinal vein occlusion. It give characteristic findings:
- Flame and blot haemorrhages
- Optic disc oedema
- Macula oedema
What investigation is used to diagnose RVO?
Fluorescein angiogram.
Other than fluorescein angiogram,, what other tests should be ordered for RVO?
Note: according to the The Royal College of Ophthalmologists
The Royal College of Ophthalmologists guidelines from 2015 suggest checking for possible associated conditions in patients presenting with retinal vein occlusion:
- Full medical history
- FBC for leukaemia
- ESR for inflammatory disorders
- Blood pressure for hypertension
- Serum glucose for diabetes
Briefly describe the treatment for RVO
Patients with suspected retinal vein occlusion should be referred immediately to an ophthalmologist for assessment and management.
Management in secondary care aims to treat macular oedema and prevent complications such as neovascularisation of the retina and iris and glaucoma. The options for this are:
- Laser photocoagulation
- Intravitreal steroids (e.g. a dexamethasone intravitreal implant)
- Anti-VEGF therapies (e.g. ranibizumab, aflibercept or bevacizumab)
What are the complications of RVO?
- Vision loss
- Vitreous haemorrhage
What differentials should be considered for RVO?
- Ischaemic optic neuropathy
- Retinal detachment (RD)
- Central retinal artery occlusion
- Optic neuritis
