Unit 5 - RVOs Flashcards
What are the three main types of RVO and their subtypes?
- BRVO ( major branch, minor branch, non-ischaemic, ischaemic)
- CRVO (non-ischaemic or ischaemic)
- HRO (non-ischaemic or ischaemic)
What is the most common form of RVO?
BRVO
What is the peak age of incidence?
65-74
What systemic investigations should be conducted?
- ESR
- Full blood count
- Blood pressure
- Serum glucose
- Fasting lipid test
What ocular investigations should be conducted?
- FFA
- OCT
- Undilated gonio to check for neovasc
- IOP
- RAPD
- VA
What is the differential diagnosis in RVO?
Diabetic retinopathy but would be bilateral and chronic rather than acute.
Ocular ischaemic syndrome
Other causes of optic disc swelling e.g. pap Radiation retinopathy
What is Virchow’s triad?
Any lumen can be obstructed by hypercoagulability, haemodynamic changes and endothelial injury.
What are the acute causes of vision loss in CRVO?
- Haem at macula
- Macula oedema
- Ischaemia of the macula
What are the chronic causes of vision loss in CRVO?
Rubeotic glaucoma
Neovascularisation - vitreous haem
What ophthalmic risk factors are there in CRVO?
- Glaucoma
- Retrobulbar external compression e.g. thyroid eye disease, orbital tumour etc.
What % of CRVO are non-ischaemic?
80%
What % of non-ischaemic convert to ischaemic in the first year?
13% (unlucky 13!)
How many disc diameters of non-perfusion is the cut off from ischaemic to non-ischaemic?
10
What v/a would you expect in ischaemic vs non-ischaemic?
<6/60 and >6/36
Would you expect an RAPD in non-ischaemic CRVO?
Non, but likely in ischaemic
Would you expect cotton wool spots in non-ischaemic?
Yes, but less than in ischaemic
How quickly will vision deteriorate in non-ischaemic?
subtle, intermittent visual loss, ischaemic will be an acute visual loss.
What follow up should be considered for an ischaemic CRVO?
- Monthly follow up for 6/12
- Monthly gonio to look for NVA
- PRP when any NVA/NVI
- Consider prophylactic PRP
What % of ischaemic CRVO patients will develop NVG?
1/3
What are optic disc collaterals and what do they do to neovasc risk?
Enlarged connections between retinal vasculature and choroid. They take about 6 months to develop and reduce neovasc risk by 25X
What are the two main ways of treating CMO?
Grid laser
Intravitreal injections (steroids or anti-VEGF)
Why is grid laser not used much?
It resolves oedema but doesn’t improve v/a
What two types of intravitreals can be used in CMO
Steroids
Anti-VEGF
Why are anti-VEGF injections effective in CMO
VEGF is highest in CRO, 80 times higher than in wet AMD.
What % of patients improved 15 letters with anti-vegf?
50%
What are the problems with steroid IV?
Cataract
High IOPs
Which area of the retina is the most likely to be effected by NVE?
The border between perfused and non-perfused retina.
What are the NICE approved treatments for BRVO?
Eylea first line
Lucentis if grid laser ineffective
Dexamethasone if grid laser ineffective/impossible
How quickly should an RVO be referred as recommended by College of Optometrists?
Urgent referral.
MEH suggests CRVO seen in an MR clinic within a month and BRVO within 3 months
What 3 phases are there in BRVO?
Acute phase: diffuse leakage, ir haems
Intermediate phase: collateral formation
Chronic phase: venous sheathing
Which study showed that steroids were as effective as anti-VEGF?
SCORE
Which study showed that anti-VEGF was better that grid laser?
VIBRANT
How can you differentiate collaterals from neovascularisation?
They originate from capillaries
They do not leak FA
Which studies showed that anti-VEGF was safe in RVO?
Lucentis - Cruise and Horizon
Eylea - Galileo and copernicus
