Non Arteritic Anterior Ischaemic Neuropathy (NAION)

Question 1

What is anterior ischaemic neuropathy?

Answer 1

The infarction (damage due to lack of blood supply) of the ONH due to occlusion of the posterior ciliary artery (PCA).

Question 2

What is the aetiology/cause of NAION?

Answer 2

• Atherosclerosis (thickening/hardening of arteries)

- Partial/Total infarction of ONH due to PCA occlusion

Question 2

What is the aetiology/cause of NAION?

Answer 2

• Atherosclerosis (thickening/hardening of arteries)

- Partial/Total infarction of ONH due to PCA occlusion

Question 3

What are predisposing factors/conditions of NAION?

Answer 3

• Hypertension
• Diabetes
• Heart Disease
• Carotid artery disease
• Ocular = Small or absent cup (hyperopia)

Question 4

Presentation/Symptoms of NAION?

Answer 4

• Age 45-65yrs
• Sudden, Unilateral, painless vision loss (noticed on waking)
• No Amaurosis Fugax (temp loss of vision in one or both eyes due to lack of blood supply)

Question 5

What are the 4 signs of NAION?

Answer 5

• Normal, Slightly Reduced or Severe VA reduction
• RAPD
• Dyschromatopsia (colour deficiency)
• Altitudinal VF defect
• Disc swelling; of ONH

Question 6

What are the 4 ONH signs for NAION?

Answer 6

• Diffuse or sectoral Oedema (Sup/Inf)
• Pale/Mild Hyperaemia
• Possible flame haemorrhages
• Small/Absent Cup in fellow eye

Question 7

What is the referral for NAION?

Answer 7

EMERGENCY SAME DAY REFERRAL

• to exclude GCA
• Concern: Permanent vision loss.

Question 8

What is the management for NAION?

Answer 8

• Carry out BIOPSY - to rule out giant cell arthritis (GCA)

- Treat underlying systemic disease (Diet, Exercise, Stop smoking)