About Amaurosis fujax
Amaurosis fujax is a symptom, which describes one-eyed visual loss, which lasts from several seconds up to several hours; followed by recovery and return of the vision to normal. The visual loss is usually profound (total blackness), either involving the whole of the field of vision or half of the field of vision; in the case of the latter it is usually either the upper or lower half, above or below the horizontal mid-line. It is a symptom that should not be ignored, and should be investigated due to the potential seriousness of the diseases that cause it. Amaurosis can be confused with the visual loss that is associated with a transient ischaemic attack (TIA) or mini-stroke. On closer questioning the symptoms will in fact involve both eyes and the field of vision to one side of the vertical mid-line. The importance of the symptoms remains the same. If the vision loss persists for more than 30 minutes you should attend the emergency department immediately.
The image on the left shows a fluorescein angiogram of a central artery occlusion – note how the dye barely passes through the vessel. In the middle a ciliretinal branch has been occluded leading to a pale swollen area in the macula. On the right there is a carotid Doppler ultrasound demonstrating a critical stenosis of the vessel
There are many possible causes for the visual loss, but most are related to obstruction of the retinal or ophthalmic arteries, either by an embolus (mechanical plug of material causing blockage), constriction of the vessel due to inflammation in the vessel wall, or compression of the vessel from outside its walls. Variations in amaurosis symptoms can be caused by other conditions.
Potential Causes
- Cranial/Temporal arteritis
- Carotid vessel obstruction (main neck blood vessel), often in conjunction with cardiac arrhythmia (irregular heart beat) leading to:
– Central or branch arterial occlusion
– Ocular ischaemic syndrome – poor blood supply to the whole eye
– Anterior ischaemic neuropathy (affecting front of optic nerve)
- Emboli from I/V drug abuse
- Optic neuritic neuritis or intracranial hypertension
- Impending retinal vein occlusion
- Retinal migraine
- Glaucoma, particularly angle-closure type
- Haemorrhage into the vitreous
- Compression from an optic nerve/orbital tumour
- Optic disc drusen (deposits in the optic nerve)
On the left are some images of optic nerve drusen. These are calcified bodies which can compress the blood vessels. On the right is a picture of a swollen optic disc such as would be found in Benign Intracranial Hypertension
Investigations required
- Immediate ESR/CRP blood test to look for inflammation
- Blood glucose to exclude diabetes
- Check Blood pressure
- Check pulse and Electrocradiogram (ECG)
- Ultrasound of carotid blood vessels
- Fluorescein angiogram to establish if there is a retinal arterial occlusion
Management
This will depend upon what is identified from the above.
See under links for treatment of specific conditions.
In the case of arterial disease and a significant blockage being identified:
- You may be asked to gently massage the eye during an episode in an attempt to dislodge the embolus.
- Very rarely, and if caught early, a surgical procedure may be offered to help dislodge the embolus.
- You will be advised to stop smoking.
- Control blood lipids (cholesterol) – with drugs if necessary.
- Carotid endarterectomy (a surgical procedure to “ream out” the carotid blood vessels). Generally this is only offered if there is more than a 75% blockage, and the risks are deemed acceptable.
- Blood pressure will need to be controlled.
- Aspirin or other blood-thinning agents may be commenced.
- Lose weight and exercise.
