Unit 5 - AION

Question 1

What parts of the optic nerve are affected in posterior optic neuropathy?

Answer 1

1. Intra-orbital
2. intra-cannicular
3. intra-cranial portions of the optic nerve with usually no visible ONH oedema.

Question 2

What are three common causes of PION

Answer 2

• Face-down spinal surgery
• Radiotherapy
• Hypotension

Question 3

What are the two main types of AION?

Answer 3

Arteritic and non-artieritic

Question 4

In what population is Arteritic AION most common?

Answer 4

White woman, mean age 70,

(rare in blacks, hispanics and under 60).

Question 5

Giant cell arteritis can cause vision loss in other ways to arteritic AION - what are they?

Answer 5

• CRAO
• Cordal ischaemia

Question 6

What proportion of GCA vision loss is due to arteritic AION?

Answer 6

80%

Question 7

What are the ocular symptoms of arteritic AION?

Answer 7

Sudden altitudinal, unilateral vision loss. Develops from hours to days.

Question 8

What are the signs of arteritic AION?

Answer 8

1. V/A and colour vision reduced if visual field affects fixation
2. RAPD
3. Oedematous disc at onset

Question 9

What 7 non-ocular symptoms may be present in arteritic AION?

Answer 9

1. Scalp tenderness
2. Frontal, temporal headaches
3. Pain on eating
4. Patient feels unwell and tired
5. Pain and stiffness in upper legs, arms and shoulders worse in the morning
6. Weight loss
7. Tenderness and prominence of temporal artery

Question 10

In what proportion of GCA are there only ocular symptoms and no systemic symptoms?

Answer 10

20%

Question 11

What systemic tests need to be conducted?

Answer 11

1. ESR
2. Temporal artery biopsy (although negative doens’t rule it out)
3. Thrombocytosis

Question 12

What is the treatment of arteritic AION?

Answer 12

High dose IV steroids followed by oral steroids Taper steroids slowly. Systemic symptoms usually subside within a week

Question 13

What recovery is there from arteritic AION?

Answer 13

Not much

Question 14

How often is the second eye affected in arteritic AION?

Answer 14

54-94% without treatment

Question 15

What are the 7 signs of Non-arteritic AION

Answer 15

1. v/a better than 6/60
2. altitudinal visual field loss (lower>upper)
3. Colour vision loss proportional to v/a loss (unlike in optic neuritis)
4. Slight to moderate RAPD
5. Small splinter haems around ONH
6. Pale ONH
7. Contralateral disc is small in diameter with small or absent cup “disc a risk”

Question 16

What 8 risk factors are there in Non-arteritic AION?

Answer 16

1. Hypertension (34-50% of cases)
2. Diabetes (5-25%)
3. Obstructive sleep apnoea
4. Hyperopia
5. Optic disc drusen
6. Elevated IOP
7. Migraine
8. Use of phospodiesteras-5 inhibitors (viagra)

Question 17

What is the prognosis in Non-arteritic AION?

Answer 17

43% gain at least 3 lines, others no change 15% will involve second eye

Optic disc becomes atrophic within 4-6 weeks

Question 18

What treatment is there for non-arteritic AION?

Answer 18

None

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