Neuro-ophthalmology: Case two

This 65 year old woman presented to the casualty with a sudden onset visual loss in the left eye which slowly resolved over a period of 30 minutes. She was referred to the cardiologist and the above investigation was performed.

a. What is the investigation?

This is a carotid contrast angiography. This is seldom performed as the investigation of choice because of its association with significant morbidity. The first line of investigation of carotid artery nowadays is with the non-invasive duplex ultrasonography.

b. What abnormality is present?

The angiography shows stenosis of the left internal carotid artery distal to the bifurcation of the carotid artery.

c. What other ocular signs may occur with this condition?

Carotid artery stenosis can give rise to ocular signs in two ways:

1. through emboli (which may be fibroplatelet, calcium deposits or cholesterol):

  •     amaurosis fugax
  •     central retinal artery occlusion
  •     ophthalmic artery occlusion
  •     visual field defects from cerebrovascular accidents
  • 2. through reduced blood flow causing ocular ischaemic syndrome with ischaemic retinopathy and

    d. What treatment options are available?

    Two options are available:

  • Use of aspirin can reduce the incidence of amaurosis fugax and is recommended in all patients with amaurosis fugax  who have no contra-indications
  • Endarterectomy: trials (North American Carotid Endarterectomy Trial and European Carotid Surgery Trial) showed the benefit of endarterectomy in patients who had  transient ischaemic attack or minor cerebrovascular accidents and had more than 70% of carotid artery stenosis provided the patients were fit for surgery. Endarterectomy reduced the incidence of TIA and CVA in symptomatic patients, however, its benefit for asympatomatic stenosis is unknown.
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