History

In addition to the history of presenting complaint, previous ophthalmic history and underlying systemic disease with potential to affect the eye, the clinician should enquire about a history of thromboembolic risk factors and conditions predisposing to retinal detachment, i.e. myopia, cataract surgery, increasing age. In sudden visual loss, certain discriminating questions may narrow the differential diagnosis:

Is there a history of trauma?

Blunt trauma to the orbit followed by flashes of light and visual loss may suggest traumatic retinal detachment.

How quickly did the disturbance appear?

A rapid onset suggests a vascular problem or retinal detachment.

A slower onset suggests a more chronic process such as optic neuritis or glaucoma.

Is the eye red?

A red eye is suggestive of inflammatory pathology, such as keratitis, uveitis or acute angle closure glaucoma.

A poorly functioning eye, which appears normal externally, should arouse suspicion of pathology in the posterior vitreous, retinal or neurovisual structure.

Is the eye painful?

CRAO/CRVO are characteristically painless, as is posterior vitreous detachment.

However, optic neuritis is associated with pain on ocular movement.

Giant cell arteritis commonly causes a temporal headache and/or pain on mastication (jaw claudication).

Are there any extraocular symptoms?

Acute angle closure glaucoma may present with headache and autonomic features such as nausea and vomiting.

Ischaemic optic neuropathy is commonly associated with headache and jaw claudication.

Dysphasia and other neurological deficits suggest an intracerebral problem.

Is the disturbance a partial or complete loss of vision?

Complete loss of vision in one eye localises pathology to that eye or optic nerve, e.g. CRAO/CRVO.

If the disturbance is partial, what form did it take?

Partial loss of vision must be differentiated between:

• Loss of part of the visual field – for example, quadrantopia, hemianopia or central scotoma
• A ‘curtain coming down’ across the vision – a typical description of a retinal detachment or amaurosis fugax in a transient ischaemic attack
• Flashes – usually due to retinal ischaemia/detachment
• Floaters – due to opacities in the vitreous which may be normal. However, a sudden increase in floaters may be caused by vitreous haemorrhage or posterior vitreous detachment
• ‘Haloes’ around bright objects with blurred vision – seen often in acute angle closure glaucoma

Learning bite

Discriminating questions early in the history can focus the differential diagnosis and allow investigation/exclusion of the most likely causes as a priority.