What are the symptoms of anterior ischemic optic neuropathy?

Updated on

What are the symptoms of anterior ischemic optic neuropathy?

There are 2 forms of AION, each with their own particular set of symptoms.

Arteritic AION (A-AION) is a dangerous condition caused by inflammation of arteries supplying blood to the optic nerve. The inflammation is due to a condition known as giant cell arteritis (GCA) or temporal arteritis, which causes inflammation of medium- and large-sized arteries. GCA is potentially fatal and can damage the entire optic nerve head leading to permanent, massive vision loss if not diagnosed and treated quickly. A-AION is found 3 times more often in women than men, and most often affects those over the age of 55.

GCA usually presents a number of symptoms before any loss of vision occurs. About 80% of those affected will feel unwell for some time with any of the following:

  • Pain in the temples
  • Pain when chewing
  • Scalp pain or tingling
  • Neck pain
  • Muscle aches and pains, particularly in the upper legs or arms
  • General fatigue
  • Loss of appetite
  • Unexplained loss of weight
  • Fever

In a less common form of GCA known as occult giant cell arteritis, no symptoms are present.

The key vision-related symptom of A-AION is painless, temporary blurriness or loss of vision lasting several minutes or hours before vision loss becomes permanent. This temporary vision loss should be taken as a warning signal. Whether 1 or both eyes are permanently affected depends on how soon the patient is seen by an eye doctor, how soon a diagnosis is made, and how quickly treatment begins.

Nonarteritic AION (NA-AION) is the most common form of AION. The majority of those affected are over the age of 50; 10% of cases are in people over age 45. However, the condition can appear at any age. Both men and women have the same rates of occurrence. NA-AION is caused not by inflammation of the arteries but by one of the following: (1) a drop in blood pressure to such a degree that blood supply to the optic nerve is decreased; (2) increased pressure inside the eyeball; (3) narrowed arteries; (4) increased blood viscosity (thickness); or (5) decreased blood flow to the optic nerve where it leaves the back of the eye. A number of diseases or conditions can cause these risk factors, putting a person at greater risk of developing NA-AION.

Risk factors include:

  • High blood pressure
  • Diabetes mellitus
  • High cholesterol
  • Smoking
  • Sleep apnea
  • Heart disease
  • Blocked arteries
  • Anemia or sudden blood loss
  • A sudden drop in blood pressure
  • Sickle cell trait
  • Vasculitis (inflammation of a blood vessels)

The main symptom of NA-AION is a sudden, painless loss or blurring of vision in one eye, usually noticed upon waking from a night’s sleep or even a nap. It is believed that the body’s normal drop in blood pressure during sleep ― along with one or more underlying risk factors ― triggers an interruption of blood flow to the optic nerve.

Note that there is no correlation between a person having poor eyesight (being nearsighted or farsighted) and the development of NA-AION.

Related posts