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.1,2
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%.
RVO can be classified anatomically based on the location of the occulsion: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 classified as ischaemic or non-ischaemic.
Ischaemic changes are associated with poorer prognosis due to retinal non-perfusion, capillary closure and retinal hypoxia, which increases the risk of neovascularisation.
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 flow and thrombus 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.
The exact cause of RVO is unknown, however, there are several associated risk factors including:1,3
Atherosclerosis: hyperlipidaemia, hypertension and diabetes
Optical coherence tomography: for assessment of macula oedema
Fundus fluorescein angiography: helps evaluate retinal capillary non-perfusion, and helps decide if ischaemic/non-ischaemic and need for laser treatment
Other relevant imaging investigations may include:
Chest X-ray: to exclude tumours, vasculitis (rarely required)
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).
Definitive ophthalmic management
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, aflibercept or bevacizumab): may help reduce vessel leakage
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
Ophthalmology follow-up is dependent on disease severity, but can initially be as frequent as every 4-6 weeks.7
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
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.8
Ischaemic presentation and occlusion complications can reduce this prognosis significantly. Retinal neovascularization occurs in about 5% of cases.
Retinal vein occlusion (RVO) refers to obstruction of retinal veins due to thrombus, resulting in retinal vascular changes.
RVO commonly presents with sudden, painless visual loss.
RVO is a clinical diagnosis, although other investigations may be utilised to exclude other causes.
Fundoscopic signs may include dot-and-blot haemorrhages, cotton wool spots, macular oedema and neovascularisation.
Prompt assessment and referral is essential to prevent further visual loss.
Management options include laser treatment, anti-VEGF agents and intravitreal steroid use, alongside systemic risk factor control.
Dr Ashley Simpson
Dr Chris Jefferies
Baldwin A, Goumalatsou C, Hjelde N, Myers G. Oxford Handbook of Clinical Specialities 10th 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.
Bowling B. Kanski’s Clinical Ophthalmology: A systematic approach 8th Ed; Elsevier; 2016.