Section 4 Management of Central Retinal Vein Occlusion
There are two aims in the management of retinal vein occlusion: the 
identification of modifiable risk factors and their medical management 
and the recognition and management of sight-threatening complications.

Although the systemic investigation and treatment in all types of vein 
occlusion is similar, the ophthalmological management of branch and 
central retinal vein occlusion differs. These will therefore be considered 

4.1 Central retinal vein occlusion
There is no proven early treatment that will alter the visual prognosis 
in established central retinal vein occlusion. The main management 
problem is to differentiate ischaemic from non-ischaemic central retinal vein 
occlusion. Patients with ischaemic CRVO are at risk of neovascular glaucoma 
for which laser photocoagulation may be beneficial. This risk of iris neovascu-
larisation is higher if the area of retinal ischaemia (retinal non-perfusion as determined by FFA) is >10 disc diameters (CVOS).18 Ischaemic central 
retinal vein occlusion is associated with one or more of the following characteristics:-
1. Poor visual acuity (44% of eyes with vision of <6/60 
    develop rubeosis [CVOS])18
2. Relative afferent pupillary defect
3. Presence of multiple dark deep intra-retinal haemorrhages
4. Presence of multiple cotton wool spots
5. Fluorescein angiography showing greater than 10 disc 
    areas of retinal capillary non-perfusion (CVOS)18
6. Electrodiagnostic tests (ERG): reduced b wave amplitude,
    reduced b:a ratio and prolonged b-wave implicit
There is no evidence as to which combination of the above characteristics 
best defines ischaemic CRVO. It is important to note that up to 30% of 
patients with initially nonischaemic central retinal vein occlusion will 
develop ischaemic transformation.24- 27
This is usually heralded by further rapid visual deterioration and requires 
further assessment. CRVO especially of the non-ischaemic type needs to 
be differentiated from the ocular ischaemic syndrome and other simulating retinopathies.
4.1.1 Management of ischaemic central retinal vein occlusion and 
anterior segment neovascularisation
An initial evaluation of risk factors and the appropriate treatment of 
the present risks must proceed alongside management of the ocular findings.
The evidence supports the use of laser pan-retinal photocoagulation 
when iris new vessels (INV) or angle new vessels (ANV) are visible. 
Monthly follow up is advised for six months in all untreated patients with 
features of retinal ischaemia and must include undilated pupil examination 
and detailed examination of the iris with gonioscopy.18 (However, this 
monthly follow up may be impracticable in some UK eye clinics). PRP should 
be applied at the earliest sign of INV and or ANV.
In circumstances when regular follow-up is impractical, prophylactic 
treatment may be appropriate.28
4.1.2 Posterior segment neovascularisation
This is an uncommon complication following ischaemic central retinal 
vein occlusion in eyes which have not developed neovascular glaucoma or 
who have been successfully treated for rubeosis by laser. It has been 
reported that this complication does not usually require active therapy.29
4.1.3 Pan-retinal Photocoagulation Technique
Pan-retinal photocoagulation for CRVO with INV or ANV requires 
1500 - 2000 of 500-micron burns at the retina. This is best applied with 
0.05-0.1 seconds applications one burn width apart with sufficient energy 
to produce a pale burn in the retina. Treatment is usually placed in the 
periphery avoiding areas of retinal haemorrhage. Some cases require further treatment if the iris neovascularisation fails to regress.18
There is an alternate view to the management of iris
neovascularisation. There is a suggestion that rubeosis does not inevitably 
lead to glaucoma and therefore laser photocoagulation should be withheld because this treatment leads to further contraction of the visual field.30 However, it is our opinion that the weight of evidence supports the recommendations stated above.18,28,31
4.1.4 Management of established neovascular glaucoma
The aim of management of this condition in a blind eye is to keep the 
eye pain free. This is usually achieved by topical steroids and atropine. 
However, if the eye has any visual potential intraocular pressure should 
be controlled with topical pressure-lowering agents or cyclo-ablative 
procedures. Drainage procedures are of limited value.
4.1.5 Macular oedema
Macular oedema following central retinal vein occlusion results from 
leakage of perifoveal capillaries. It results in visual loss but there is no 
proven treatment for this condition. Randomised controlled trials have 
failed to indicate benefit from grid treatment, although a trend in favour 
of treatment has been observed in younger patients.32 Although there 
was significant reduction in the severity of macular oedema in treated 
eyes compared to controls there was no visual acuity benefit.
4.2 Recommendations for Further Follow-up
Follow-up after 6 months for ischaemia (> 10DD non-perfusion) should 
be every 3 months for 1 year. Non ischaemic eyes should have initial follow 
up every 3 months for 6 months. Subsequent follow-up for all patients will 
depend upon laser treatment and complications but will not normally be 
required after 2 years in uncomplicated cases. The development of disc 
collaterals +/- resolution of the CRVO should lead to discharge from 
clinical supervision.
Experimental treatments
Chorio-retinal anastomosis is an experimental treatment and the results 
of randomised trials of this therapy are awaited. However, there are 
significant complications associated with laser-assisted chorioretinal venous anastomosis eg choroidal neovascularisation33, retinal and subretinal fibrosis 
or traction34,and vitreous haemorrhage.35
Trials of other treatments such as radial optic neurotomy with pars plana vitrectomy, and thrombolytic therapies are under way. These, however, are 
only experimental at present and are, therefore, not recommended except 
as part of clinical trials.
Introduction Methods used Risk factors CRVO
BRVO Medical treatment Cardiovascular problems Young patient
References. Tables Main index Main page.