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Eye clinic – Hemiretinal vein occlusion

Ophthalmologists Miss Claire Daniel, Miss Seema Verma and Miss Lola Ogunbowale discuss this condition's management

A 45-year-old man presents with a two-day history of blurred vision, without pain, redness, history of trauma or headache, and with no preceding floaters or flashing lights. The vision in his right eye is poor due to an old corneal scar. Recently he was found to have slightly raised blood pressure.


Examination reveals visual acuities of hand movements in the right eye and 6/9 in the left eye. Anterior segment examination is normal except for the corneal scar; intra-ocular pressures are normal. Dilated fundal examination (see right) reveals multiple scattered retinal haemorrhages with cotton-wool spots and tortuous dilated blood vessels in the inferior half of the fundus. The inferior half of the optic disc also reveals haemorrhages and swelling. The patient is diagnosed with hemiretinal vein occlusion.

The problem

Vein occlusion – obstruction of the retinal veins by thrombus formation – is common, and may involve the central, hemicentral or branch retinal vein. It typically occurs in older patients, and there is an equal sex distribution. Established cardiovascular risk factors are associated with vein occlusions.


The condition is characterised by swelling of the optic disc, increased tortuosity and dilatation of the retinal veins.

There are also widespread superficial and deep haemorrhages, retinal oedema, cotton-wool spots and non-perfusion of the capillaries.

Differential diagnosis

• Diabetic retinopathy

• Hypertensive retinopathy

• Sickle cell retinopathy

• Cytomegalovirus retinitis.


Urgent referral is necessary to determine whether the occlusion is ischaemic.

Patients with ischaemic occlusions are at greater risk of developing neovascular glaucoma – when there is new vessel formation in response to the ischaemic stimulus in the iris and anterior chamber angle of the eye – and they need to be monitored closely.


Management of the risk factors is as important as management of the ocular findings. For ischaemic vein occlusions, retinal laser photocoagulation is used when there are signs of new vessel formation in the iris or angle.

Recent evidence also suggests the use of anti-vascular endothelial growth factor in combination with laser treatment for treating new vessels.

Miss Claire Daniel and Miss Seema Verma are consultant ophthalmologists and Miss Lola Ogunbowale is a clinical fellow at Moorfields Eye Hospital, London

Further reading

The Royal College of Ophthalmologists. Interim guidelines for management of retinal vein occlusion. December 2010


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