Amaurosis: what it is, symptoms, causes and treatment

By Cristiano Antonino On Jan 20, 2023

Amaurosis is not a pathology, it is more properly defined as a symptom of another problem and can be caused by various causes

In clinical terms, it consists of a transient reduction in monocular visual acuity, i.e. leading to visual loss in only one eye.

This symptom is the result of a sudden and temporary hypoperfusion of the eyeball, caused by embolism or injury to the optic pathways.

Amaurosis, called fugacious, is also associated with the symptom of a transient ischaemic attack, embolic stroke or tombola and head trauma. Finally, vision loss can also occur as a consequence of degenerative changes, tumours or intoxication.

Symptoms of amaurosis

The symptoms that presage amaurosis are certainly the sudden loss of vision in one or both eyes, for a period of time ranging from a few seconds to several minutes.

Afterwards, vision returns to normal.

Some people describe it as a grey or black shadow falling over the eye.

False signals

However, it may also be the case that a sudden onset of symptoms may just be a sudden appreciation.

For example, a person with long-standing reduced vision in one eye (perhaps caused by a dense cataract) may suddenly realise the visual deficit in the affected eye when the other is covered.

The causes of amaurosis

When a sudden clot or plaque blocks an ocular artery, momentary loss of vision and thus amaurosis can occur.

The clot or plaque usually travels through a large artery, such as the carotid artery in the neck or a cardiac artery, and into the eye.

Plaque is a hard substance that forms when fat, cholesterol and other substances concentrate on the walls of arteries.

Plaque can be caused by the following factors

heart problems such as irregular heartbeat;
cocaine;
alcohol;
diabetes;
high blood pressure;
age;
having had a family history of heart attacks.

This disorder can also occur for other reasons such as:

inflammation of the optic nerve (optic neuritis);
migraines;
brain tumours;
head trauma;
systemic lupus erythematosus, an autoimmune disorder in which cells of the immune system attack healthy body tissue;
polyarteritis nodosa.

Less serious causes

Less common causes of sudden vision loss are stroke or transient ischaemic attack, acute glaucoma, retinal detachment, inflammation of the structures in front of the eye between the cornea and the lens (anterior uveitis, sometimes called iritis).

Finally, certain retinal infections and haemorrhage in the retina as a complication of age-related macular degeneration can also occur.

Amaurosis, when to see a doctor?

Vision loss, which in this case occurs suddenly, is an emergency.

Most of the time it is severe.

Therefore, if it occurs, it is absolutely necessary to visit an ophthalmologist, i.e. a doctor specialised in the assessment and treatment, surgical or otherwise, of eye disorders, or to the emergency room.

What the doctor does

The doctor immediately carries out an anamnesis, asking the patient various questions.

This is an objective test.

Often the findings of the anamnesis and the objective examination indicate the cause and any tests that may be necessary.

Questions that can be asked of the subject are, for example, when the loss occurred, whether the loss affects one or both eyes, whether it is total or only affects a specific part of the visual field, etc.

The specialist then goes on to check for other visual symptoms, such as moving bodies, flashes, distorted colour vision, halos around lights, mosaic or zig-zag patterns.

Next comes the objective test, which consists of checking the eyes.

However, the doctor may also perform a general objective test, including checking the skin and nervous system.

Checking eyesight in case of amaurosis

For the eye examination, the doctor first of all carefully checks the sharpness of vision (visual acuity), usually by having the subject read letters on a chart, first with one eye covered and then with both eyes uncovered.

The ophthalmologist checks pupil constriction in response to light and how the eyes follow a moving object.

Colour vision can be assessed.

Using a slit lamp, i.e. an instrument that allows the eye to be examined at high magnification, the doctor finally measures the intraocular pressure.

What tests are prescribed for amaurosis?

The specialist’s thorough eye test for amaurosis will reveal a clear spot where the clot is blocking the retinal artery.

The specialist may prescribe the following tests

ultrasound or angiography of the carotid artery to check for clots or plaques.
blood tests to check cholesterol levels and blood sugar.
Checking the heart, such as an electrocardiogram to check its electrical activity.

Treatment of amaurosis

The treatment for amaurosis depends on its causes.

When amaurosis is caused by a clot or plaque, the most important aim is to prevent a heart attack.

In this case one must:

avoid fatty foods and follow a low-fat diet;
do not drink more than 1 or 2 glasses of alcoholic beverages per day;
do sport regularly. 30 minutes a day if you are not overweight, 60-90 minutes a day if you are overweight;
stop smoking.

One should maintain a blood pressure between 120-130 over 80 mmHg.

If you have diabetes or a heart attack, your doctor will be able to advise you on the optimum value to achieve.

Also in the case of high blood pressure, diabetes, high cholesterol or heart disease, it is important to rely on the doctor and follow his therapy.

The specialist may also recommend no treatment at all, as the patient may only need regular visits to check the health of the heart and carotid arteries.

Take aspirin or warfarin (Coumadin) or other medicines that thin the blood and thus decrease the risk of a heart attack.

Finally, if a large part of the carotid arteries is blocked, a surgical procedure called endarterectomy is necessary to remove the obstruction.