#40. ischaemic optic neuropathy. Optic atrophy – primary and secondary

Question 1

What are the 3 Main CONDITIONS of ISCHAEMIC OPTIC NEUROPATHY?

Answer 1

1) ANTERIOR Ischaemic Optic Neuropathy

2) NON-ARTERITIC Anterior Ischaemic Optic Neuropathy

3) ARTERITIC Anterior Ischaemic Optic Neuropathy

Question 2

What is ANTERIOR Ischaemic Optic Neuropathy?

And Their 2 Forms?

Answer 2

• Involves LOSS of VISION
• DUE to Optic Nerve DAMAGE, resulting in INSUFFICIENT Blood Supply
• There are 2 Forms
  a. NON-ARTERITIC Anterior Ischaemic Optic Neuropathy = LOSS of Vision, due to Non-inflammatory Disease of SMALL Blood Vessels

b. ARTERITIC Anterior Ischaemic Optic Neuropathy = LOSS of Vision, due to INFLAMMATORY DISEASE of Arteries in HEAD, called TEMPORAL ARTHERITIS

Question 3

Describe NON-ARTERITIC Anterior Ischaemic Optic Neuropathy

Answer 3

• Unknown Cause
• It is the MOST COMMON Type
• Occurs in Individuals OVER 40 y/o
• Px tend to have UNDERLYING High BP, Diabetes, Sleep Apnoea, HIGH Cholesterol
• Smoking is a RF to develop this condition

Question 4

Describe ARTERITIC Anterior Ischaemic Optic Neuropathy

Answer 4

• LESS COMMON Type
• Occurs in Individuals OVER 50 y/o
• LOSS of Vision, due to INFLAMMATORY DISEASE of Medium-Large Sized BV’s, including those IN THE EYE
• Unknown Cause HOWEVER, the INFLAMMATION CAUSES Loss of BF to the OPTIC NERVE

Question 5

What are the CLINICAL FEATURES of ISCHAEMIC OPTIC NEUROPATHY?

Answer 5

• SUDDEN Loss of CENTRAL / SIDE Vision
• Headaches, Tenderness OVER TEMPLE REGION - due to Temporal Arteritis
• Joint Aches + Pain, in Shoulders and Hips
• Tiredness, Fever & Weight Loss

Question 6

What is the DIAGNOSIS for ISCHAEMIC OPTIC NEUROPATHY?

Answer 6

1) COMPLETE EYE EXAMINATION
- Checking Pupil Dilation
- DECREASED BF results in SWELLING of Optic Nerve

2) TEST OF VISUAL FIELD (Side Vision)
- ALSO a Blood Test / Biopsy of Artery IN TEMPLE to diagnose for Temporal Arteritis

Question 7

What is the TREATMENT for ISCHAEMIC OPTIC NEUROPATHY?

Answer 7

1) NON-ARTERITIC Anterior Ischaemic Optic Neuropathy

• NO PROVEN Tx
• Underlying Diabetes, High BP, High Cholesterol, Sleep Apnoea to be KEPT UNDER CONTROL

2) TEMPORAL ARTERITIS
- HIGH Chance of Losing Vision in OTHER EYE unless Tx starts

• STEROIDS at HIGH Dosage = ANTI-INFLAMMAOTRY Effects DECREASE the Risk of Losing Vision

Question 8

What is OPTIC ATROPHY?

Answer 8

DEGENERATION of the Optic Nerve

• DUE to Pathological Processes that DAMAGE AXONS in the ANTERIOR Visual System - FROM Retinal Ganglion Cells TO Lateral Geniculate Body

Question 9

What are the 2 Types of OPTIC ATROPHY?

Answer 9

1) PRIMARY Optic Atrophy
2) SECONDARY Optic Atrophy

Question 10

What is PRIMARY Optic Atrophy?

Give an Example

Answer 10

• SIMPLE DEGENERATION of the Nerve Fibres
• WITHOUT any COMPLICATING Process within the eye

E.g. SYPHILITIC Optic Atrophy of TABES DORSALIS

Question 11

What is SECONDARY Optic Atrophy?

Answer 11

• Occurs AFTER a PATHOLOGIC Process, which PRODUCES :

a. Optic Neuritis
b. Papilloedema

Question 12

What are the CLINICAL FEATURES of OPTIC ATROPHY?

Answer 12

1) LOSS OF VISION
- Sudden / Gradual Onset
- Partial / Total Atrophy

2) Pupil is SEMI-DILATED
- DIRECT Light Reflex is SLUGGISH / ABSENT
- Swinging Flash Light Test = Shows MARCUS GUNN PUPIL

3) VISUAL FIELD LOSS
- Varies with Distribution of Fibres DAMAGED
- PERIPHERAL = Systemic Infections
- CENTRAL = Focal Optic Neuritis
- ECCENTRIC = Nerve / Tracts are COMPRESSED

4) PALLOR of DISC / DECREASE in N.O of Small BV
- Pallor is DUE to LOSS of VASCULATURE

• Optic Nerve sends information from Retina to Brain - DAMAGE will result in VISION LOSS
• SUBTLE DAMAGE can lead to LOSS of CONTRAST / COLOUR VISION
• SEVERE DAMAGE can lead to NO LIGHT PERCEPTION