Systemic Disease and Optic Nerve Flashcards
Anatomy of Optic Nerve?
- How many fibres? Type of nerve fibres? Origin?
- Where do they synapse?
- Where do fibres subserve in Visual Field?
- 1.2 million afferent nerve fibres
Originate in the retinal ganglion cells - Most synapse in the lateral geniculate body (some go to the pre-tectalnuclei in the midbrain)
- About 1/3 of the fibres subserve the central 5°of the visual field
Describe the optic disk?
- Shape?
- Colour?
- Diameter?
- Circular or oval structure
- Pale pink.
The temporal side being slightly lighter than the nasal - ~1.5mm in diameter

- What does optic disc contain?
- Describe disc edge?
- The centre has a small depression = physiological cup.
- Disc edges are flat and well defined and the temporal edge is more distinct than the nasal

- What is pigmented arc?
- What does it make up of?
- It is formed when retina does not reach the optic disc margin
- Choroidal pigment

- What artery is in Optic disc?
- What are their branches?
- The central retinal artery appears on the surface of the optic disc.
- It divides into two branches: superior & inferior

- Where do optic nerve fibres become myelinated?
- Lamina cribrosa ( where they exit eyeball)
( Image: paler sheathing, fibres are arcuated)

Anatomical subdivisions
- How long is the optic nerve between globe to chiasm?
- How many segments? How are they subdivided?
- 50mm
-
4 segments
Intraocular
Intraorbital
Intracanallicular
Intracranial
Signs of Optic nerve problems?
1. VA?
- Pupil?
- Colour vision
- Sensitivity?
- Any visual field defects?
- VA decrease
- Afferent pupil defect
- Dyschromatopsia
- Colour vision impairment
- Mainly affects red or green
- Quick assessment: ask patient to compare colour of a red object
- Diminished light brightness sensitivity
- Visual field defects
Underlying disease?
- How to find out underlying disease?
- What factors to be considered?
- Careful examination & history taking is essential !!!
- Consider:
- Raised ICP
- Intracranial hypertension: associated with prescription & non-prescription drugs
- Ischaemia: Associated with atherosclerosis, diabetes & giant cell arteritis
- Thyroid disease
Optic Atrophy Signs?
Primary
- Apperance of ONH?
- What cause (1)?
- Appearance of optic disc? Margin?
- Vessels on disc surface?
- NFL?
Primary
- No swelling at ON head
- Caused by lesions of visual pathway
- Pale flat disc with clear margins
- ↓ # of vessels on disc surface (Kestenbaum sign) with attenuation
- Thinning of NFL
Secondary
- Occurs after swelling at ON head
- White or grey slightly raised disc- Blurry margins
- Kestenbaum sign

Optic Atrophy Causes?
PRIMARY?
- Retrobulbar neuritis
-
Compression
Tumour
Aneurysm - Hereditary neuropathies
-
Other neuropathies
Toxic
Nutritional
Optic Atrophy Causes
Secondary?
- Papilloedema
- Anterior ischaemic optic neuropathy
- Papillitis
OPTIC NEURITIS
- What is it?
- How is it classified ?
- Inflammation , infection or demyelination of optic nerve
- By appearance or aetiology
OPTIC NEURITIS
Classification?
- Retrobulbar neuritis
- Papillitis
- Neuroretinitis
Charateristics of Optic neuritis ?
Describe ONH, Optic disc, RNFL?
- Retrobulbarneuritis
ON head looks normal initially
Associated with MS
-
Papillitis
Affects ON head
Disc becomes oedematous
Associated with peripapillaryflame haemorrhage -
Neuroretinitis
Affects ON head (papillitis)
RNFL inflammation & macular star
Least common type of neuritis

Differential diagnosis of macular star?
Other disorder causing macular star?
Hypertensive retinopathy
- Also have cotton wool spots
- Hard exudate ( due to hypertension)
- Some haemorrhage

OPTIC NEURITIS
Classification by aetilogy?
- Demyelinating
- Parainfectious
- Infectious
Optic Neuritis - Demyelinating
Consequences?
Causes?
- Myelin is lost from nerve fibres
- Disrupts nervous conduction
- Can be caused by diseases such as:
Isolated optic neuritis
Multiple sclerosis
Optic Neuritis & Multiple Sclerosis
Associated with any systemic disease clinically?
- 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
Optic neuritis -demyelinating
- Age group
- VA? Prognosis of VA?
- Signs and Symptoms?
- Presentation b/w age of 20 & 50
- Monocular VA decrease (6/18-6/60), VA recovers to 6/9 or better in 75% of cases
- Phosphenes = white/coloured flashes/sparkles
•Discomfort/pain, especially on ocular movement
•Afferent pupil defect
Optic neuritis -demyelinating
Visual field defect?
- Visual field defects are often present
↓ sensitivity in central 30° - Nerve fibre bundle defects and
Central scotomas
Focal defects

Optic neuritis -parainfectious
- Causes? What kind of infections?
- When do they occur?
- Who are more likely to be affected?
- What do patients present with?
- Optic disc appearance?
- Viral infections: Measles, mumps, chickenpox, rubella, whooping cough and glandular fever
- Occur following immunization
- Children affected more frequently than adults
- Presentation usually 1-3 weeks following a viral infection with acute severe visual loss (can be bilateral)
Other neurological features:headache, seizures or ataxia - Papillitis seen at the optic disc or can look normal
Optic neuritis -infectious
Associate with what kind of infections?
Hint: 6 !
S C S L C V
- Sinus infection which spreads and puts pressure on the nerve
- Cat-scratch fever
- Syphilis
- Lyme disease (infection from a tick bite)
- Cryptococcal meningitis (seen in AIDS patients)
- Varicella zoster virus
Optic neuritis –non-infectious
- Who does it affect?
- ON appearance?
- Affects about 1-5% of patients with sarcoidosis
- Often the optic nerve looks similar to the way it looks with MS
OPTIC NEUROPATHIES
Types?
- NAION: Non-arteritic anterior ischaemic optic neuropathy
- AAION: Arteriticanterior ischaemic optic neuropathy
- PION: PAPILLOEDEMA
NAION
Non-arteritic anterior ischaemic optic neuropathy
- Who are prone?
- Cause?
- Age?
- The elderly
- Infarction of the optic nerve head b/c of blockage of the short posterior ciliary arteries
- 55 and 70 years
NAION
Non-arteritic anterior ischaemic optic neuropathy
Prediposing factors? ( 5)
- Hypertension, ↑ cholesterol
- Diabetes mellitus, Collagen vascular disease
- Sudden hypotensive events, Cataract surgery
- Sleep apnoea
- Taking “Viagra”
NAION
Non-arteritic anterior ischaemic optic neuropathy
Signs, symptoms?
- sudden, painless, monocular visual loss
- vision is reduced upon waking
NAION
Non-arteritic anterior ischaemic optic neuropathy
Clincal Consequences?
- Vision ?
- VF defect?
- Colour vision loss?
- Optic disc?
- ↓ 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

AAION
Arteriticanterior ischaemic optic neruopathy
- Cause?
- Present with?
- Other signs & symptoms?
- Caused by Giant Cell arteritis
- Sudden & severe unilateral visual loss
periocularpain
Possibly flashing lights (photopsia) -
Other signs/symptoms
Jaw claudication
Headache of recent onset
Scalp tenderness
Weight loss
History of polymyalgiarheumatica

AAION
Arteriticanterior ischaemic optic neruopathy

NAION vs AAION
Comparison
- Vision loss ? Sign & Symptoms?

PAPILLOEDEMA
- Optic nerve head appearance?
- Causes?
- Link to intracranial mass?
-
Swelling of ONH, secondary to raised intracranial pressure (ICP)
Usually bilateral, could be asymmetrical - Other causes of disc oedema in the absence of raised ICP are referred to as ‘disc swelling’ and usually produce visual impairment.
- All patients with papilloedema should be suspected of having an intracranial mass unless proved otherwise!!!
Papilloedema
- Signs? Symptoms?
- Headache
- Sudden nausea & vomiting
- Drowsiness or deterioration of consciousness
- Transient visual obscurance
- Horizontal diplopia (c/b CN VI palsy)
Papilloedema
Stages?
4 stages:
- Early
- Established
- Chronic
- Atrophic
Papilloedema
Stage 1- Early
- Symptoms? Vision?
- Optic disc?
- Disc margin?
- No symptoms, normal vision
- Mildly elevated discs
- Indistinct disc margins i_nitially nasal_, later superior, inferior and temporal

Papilloedema
Stage 2 -Established
- Symptoms? Vision? VA?
- Optic disc?
- Fundus appearance?
-
Transient visual obscurations, lasting a few seconds
VA is normal or reduced - Optic discs elevated with indistinct margins
- Venous engorgement, peripapillary flame-shaped haemorrhages and CW spots

Papilloedema -Established
- Changes in ONH? Cause?
- Centre of fovea appearance?
- Blind spot?
- As the swelling increases, the optic nerve head appears enlarged
- 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
- The blind spot is enlarged

Papilloedema -Chronic
- VA?
- VF?
- Disc?
- Fundus apperance?
- Variable VA
- VF constriction
- Elevated discs
- No CW spots or haemorrhages

Papilloedema -Atrophic
1. VA?
- Optic disc? Colour? Margin?
- Severe VA impairment
- Discs dirty grey in colour
* *Elevated**
* *Indistinct** margins
