Systemic Disease and Optic Nerve

Question 1

Anatomy of Optic Nerve?

1. How many fibres? Type of nerve fibres? Origin?
2. Where do they synapse?
3. Where do fibres subserve in Visual Field?

Answer 1

1. 1.2 million afferent nerve fibres
   Originate in the retinal ganglion cells
2. Most synapse in the lateral geniculate body (some go to the pre-tectalnuclei in the midbrain)
3. About 1/3 of the fibres subserve the central 5°of the visual field

Question 2

Describe the optic disk?

1. Shape?
2. Colour?
3. Diameter?

Answer 2

1. Circular or oval structure
2. Pale pink.
   The temporal side being slightly lighter than the nasal
3. ~1.5mm in diameter

Question 3

1. What does optic disc contain?
2. Describe disc edge?

Answer 3

1. The centre has a small depression = physiological cup.
2. Disc edges are flat and well defined and the temporal edge is more distinct than the nasal

Question 4

1. What is pigmented arc?
2. What does it make up of?

Answer 4

1. It is formed when retina does not reach the optic disc margin
2. Choroidal pigment

Question 5

1. What artery is in Optic disc?
2. What are their branches?

Answer 5

1. The central retinal artery appears on the surface of the optic disc.
2. It divides into two branches: superior & inferior

Question 6

1. Where do optic nerve fibres become myelinated?

Answer 6

1. Lamina cribrosa ( where they exit eyeball)
   ( Image: paler sheathing, fibres are arcuated)

Question 7

Anatomical subdivisions

1. How long is the optic nerve between globe to chiasm?
2. How many segments? How are they subdivided?

Answer 7

1. 50mm
2. 4 segments
   Intraocular

Intraorbital

Intracanallicular

Intracranial

Question 8

Signs of Optic nerve problems?
1. VA?

2. Pupil?
3. Colour vision
4. Sensitivity?
5. Any visual field defects?

Answer 8

1. VA decrease
2. Afferent pupil defect
3. Dyschromatopsia

• Colour vision impairment
• Mainly affects red or green
• Quick assessment: ask patient to compare colour of a red object

4. Diminished light brightness sensitivity
5. Visual field defects

Question 9

Underlying disease?

1. How to find out underlying disease?
2. What factors to be considered?

Answer 9

1. Careful examination & history taking is essential !!!
2. Consider:

• Raised ICP
• Intracranial hypertension: associated with prescription & non-prescription drugs
• Ischaemia: Associated with atherosclerosis, diabetes & giant cell arteritis
• Thyroid disease

Question 10

Optic Atrophy Signs?

Primary

1. Apperance of ONH?
2. What cause (1)?
3. Appearance of optic disc? Margin?
4. Vessels on disc surface?
5. NFL?

Answer 10

Primary

1. No swelling at ON head
2. Caused by lesions of visual pathway
3. Pale flat disc with clear margins
4. ↓ # of vessels on disc surface (Kestenbaum sign) with attenuation
5. Thinning of NFL

Secondary

1. Occurs after swelling at ON head
2. White or grey slightly raised disc- Blurry margins
3. Kestenbaum sign

Question 11

Optic Atrophy Causes?

PRIMARY?

Answer 11

• Retrobulbar neuritis
• Compression
  Tumour
  Aneurysm
• Hereditary neuropathies
• Other neuropathies
  Toxic
  Nutritional

Question 12

Optic Atrophy Causes

Secondary?

Answer 12

• Papilloedema
• Anterior ischaemic optic neuropathy
• Papillitis

Question 13

OPTIC NEURITIS

1. What is it?
2. How is it classified ?

Answer 13

1. Inflammation , infection or demyelination of optic nerve
2. By appearance or aetiology

Question 14

OPTIC NEURITIS

Classification?

Answer 14

1. Retrobulbar neuritis
2. Papillitis
3. Neuroretinitis

Question 15

Charateristics of Optic neuritis ?
Describe ONH, Optic disc, RNFL?

Answer 15

1. Retrobulbarneuritis

ON head looks normal initially

Associated with MS

2. Papillitis
   Affects ON head
   Disc becomes oedematous
   Associated with peripapillaryflame haemorrhage
3. Neuroretinitis
   Affects ON head (papillitis)
   RNFL inflammation & macular star
   Least common type of neuritis

Question 16

Differential diagnosis of macular star?
Other disorder causing macular star?

Answer 16

Hypertensive retinopathy

• Also have cotton wool spots
• Hard exudate ( due to hypertension)
• Some haemorrhage

Question 17

OPTIC NEURITIS

Classification by aetilogy?

Answer 17

1. Demyelinating
2. Parainfectious
3. Infectious

Question 18

Optic Neuritis - Demyelinating
Consequences?

Causes?

Answer 18

• Myelin is lost from nerve fibres
• Disrupts nervous conduction
• Can be caused by diseases such as:
  Isolated optic neuritis
  Multiple sclerosis

Question 19

Optic Neuritis & Multiple Sclerosis

Associated with any systemic disease clinically?

Answer 19

• Some patients with optic neuritis have no clinically demonstrable associated systemic disease but a close association exists between the two
• ~ 15-20% of MS patients present with optic neuritis and optic neuritis occurs at some point in 50% of patients with MS

Question 20

Optic neuritis -demyelinating

1. Age group
2. VA? Prognosis of VA?
3. Signs and Symptoms?

Answer 20

1. Presentation b/w age of 20 & 50
2. Monocular VA decrease (6/18-6/60), VA recovers to 6/9 or better in 75% of cases
3. Phosphenes = white/coloured flashes/sparkles

•Discomfort/pain, especially on ocular movement

•Afferent pupil defect

Question 21

Optic neuritis -demyelinating
Visual field defect?

Answer 21

• Visual field defects are often present
  ↓ sensitivity in central 30°
• Nerve fibre bundle defects and
  Central scotomas
  Focal defects

Question 22

Optic neuritis -parainfectious

1. Causes? What kind of infections?
2. When do they occur?
3. Who are more likely to be affected?
4. What do patients present with?
5. Optic disc appearance?

Answer 22

1. Viral infections: Measles, mumps, chickenpox, rubella, whooping cough and glandular fever
2. Occur following immunization
3. Children affected more frequently than adults
4. Presentation usually 1-3 weeks following a viral infection with acute severe visual loss (can be bilateral)
   Other neurological features:headache, seizures or ataxia
5. Papillitis seen at the optic disc or can look normal

Question 23

Optic neuritis -infectious
Associate with what kind of infections?
Hint: 6 !
S C S L C V

Answer 23

1. Sinus infection which spreads and puts pressure on the nerve
2. Cat-scratch fever
3. Syphilis
4. Lyme disease (infection from a tick bite)
5. Cryptococcal meningitis (seen in AIDS patients)
6. Varicella zoster virus

Question 24

Optic neuritis –non-infectious

1. Who does it affect?
2. ON appearance?

Answer 24

1. Affects about 1-5% of patients with sarcoidosis
2. Often the optic nerve looks similar to the way it looks with MS

Question 26

**OPTIC NEUROPATHIES** Types?

Answer 26

1. **NAION:** Non-arteritic anterior ischaemic optic neuropathy 2. **AAION:** Arteriticanterior ischaemic optic neuropathy 3. **PION:** PAPILLOEDEMA

Question 27

**NAION** **Non-arteritic anterior ischaemic optic neuropathy** 1. Who are prone? 2. Cause? 3. Age?

Answer 27

1. The **elderly** 2. **Infarction of the optic nerve head** b/c of _blockage of the short posterior ciliary arteries_ 3. **55 and 70** years

Question 28

**NAION** **Non-arteritic anterior ischaemic optic neuropathy** Prediposing factors? ( 5)

Answer 28

1. Hypertension, ↑ cholesterol 2. Diabetes mellitus, Collagen vascular disease 3. Sudden hypotensive events, Cataract surgery 4. Sleep apnoea 5. Taking “Viagra”

Question 29

**NAION** **Non-arteritic anterior ischaemic optic neuropathy** Signs, symptoms?

Answer 29

* **sudden, painless, monocular visual loss** * vision is reduced upon waking

Question 30

**NAION** **Non-arteritic anterior ischaemic optic neuropathy** Clincal Consequences? 1. Vision ? 2. VF defect? 3. Colour vision loss? 4. Optic disc?

Answer 30

* **↓ vision** ~1/3 of patients will have normal/near normal vision * VF defect: Often **inferior altitudinal** * **Colour vision loss** * **Swollen optic disc** **_Image:_** **_​_**a. Swollen disc, diffuse oedema b. Blurred edge, sectorial haemorrage c. haemorrage at Superior nasal sector d. leaking blood - lack of perfusion

Question 31

**AAION** **Arteriticanterior ischaemic optic neruopathy** 1. Cause? 2. Present with? 3. Other signs & symptoms?

Answer 31

1. Caused by **_Giant Cell arteritis_** 2. *Sudden & severe **unilateral** visual loss periocular**pain** Possibly flashing lights (photopsia)* 3. *_Other signs/symptoms_* Jaw claudication Headache of recent onset Scalp tenderness Weight loss History of polymyalgiarheumatica

Question 32

AAION Arteriticanterior ischaemic optic neruopathy

Answer 32

Question 33

NAION vs AAION Comparison 1. Vision loss ? Sign & Symptoms?

Answer 33

Question 34

**PAPILLOEDEMA** 1. Optic nerve head appearance? 2. Causes? 3. Link to intracranial mass?

Answer 34

1. **Swelling** of ONH, _secondary_ to raised intracranial pressure **(ICP)** Usually **bilateral**, could be **asymmetrical** 2. Other causes of disc oedema in the absence of raised ICP are referred to as '**disc swelling'** and usually produce **visual impairment.** 3. _All patients with papilloedema should be **suspected of having an intracranial mass** unless proved otherwise!!!_

Question 35

**Papilloedema** 1. Signs? Symptoms?

Answer 35

1. Headache * Sudden nausea & vomiting * Drowsiness or deterioration of consciousness * Transient visual obscurance * Horizontal diplopia (c/b CN VI palsy)

Question 36

**Papilloedema** Stages?

Answer 36

***4 stages:*** 1. Early 2. Established 3. Chronic 4. Atrophic

Question 37

**Papilloedema** **Stage 1- Early** 1. Symptoms? Vision? 2. Optic disc? 3. Disc margin?

Answer 37

1. *No symptoms*, normal vision 2. **Mildly elevated** discs 3. **Indistinct** disc margins i_nitially nasal_, later superior, inferior and temporal

Question 38

**Papilloedema** **Stage 2 -Established** 1. Symptoms? Vision? VA? 2. Optic disc? 3. Fundus appearance?

Answer 38

1. **Transient visual obscuration**s, lasting a few seconds VA is normal or reduced 2. Optic discs **elevated with indistinc**t margins 3. *Venous **engorgement,** peripapillary f**lame-shaped** haemorrhages and **CW s**pots*

Question 39

Papilloedema -Established 1. Changes in ONH? Cause? 2. Centre of fovea appearance? 3. Blind spot?

Answer 39

1. As the **swelling increases**, the optic nerve head appears **enlarged** 2. **Hard exudates** may radiate from the centre of the fovea in the form of a **'macular fan**' -an incomplete star with the temporal part missing 3. The blind spot is **enlarged**

Question 40

**Papilloedema -Chronic** 1. VA? 2. VF? 3. Disc? 4. Fundus apperance?

Answer 40

1. Variable VA 2. VF constriction 3. Elevated discs 4. No CW spots or haemorrhages

Question 41

Papilloedema -Atrophic 1. VA? 2. Optic disc? Colour? Margin?

Answer 41

1. **Severe VA impairment** 2. Discs dirty **grey** in colour * *Elevated** * *Indistinct** margins