OPTIC NERVE DISEASE IN NEUROOPHTHOMOLOGY

For any ophthomology student

1. OPTIC NERVE DISEASE
Prof. Than Aung

2. ANATOMY
•Afferent fibres: 1.2 million; originate in
RGC, synapse in LGB; 1/3 fibres = central
5 degree of VF
•Oligodendrocytes: myelination
•Microglia: immunocompetent phagocytic
cells; modulate apoptosis of RGC
•Astrocytes: glial supporting cells

3. Anatomical subdivisions
•50mm long from globe to chiasma
•1. Intraocular: 1mm long x 1.5mm diam;
prelaminar & lamina cribrosa containing
200-300 channels; SPCA through circle of
Zinn-Haller & recurrent choroidal arteries

4. Anatomical subdivisions
•2. Intraorbital: 25-30mm long x 3mm diam;
acquires myelin; at apex surrounded by
annulus of Zinn; full meningeal sheaths;
subarachnoid space continuous with
cerebral subarachnoid; pial plexus fed by
branches of OA

5. •3. Intracanalicular: 6mm long; fixed to the
canal since dura mater fused with the
periosteum; pial plexus
•4. Intracranial: 8-16mm long; no sheath;
frontal lobes above, ICA laterally; pial
plexus & superior hypophyseal artery

6. PHYSIOLOGY
•Axoplasmic transport: orthograde and
retrograde transport of metabolic products;
active mechanism requiring high oxygen;
sensitive to ischaemia, inflammation,
toxins and compression

7. OPTIC NERVE DYSFUNCTION
•1. Reduced VA: D & N
•2. RAPD: unilateral / asymmetrical
•3. Dyschromatopsia: mainly red & green
•4. Diminished light sensitivity: may persist

8. • 5. Diminished contrast sensitivity
•6. Visual field defects: diffuse depression
of central field, centrocaecal / central
scotoma, NF bundle defect, altitudinal
•7. Optic disc abnormalities: swelling,
pallor, etc.

9. OPTIC NEUROPATHY
1. Inflammation: - demyelinating
- parainfectious
- infectious
- autoimmune
2. Ischaemic: - Arteritic AION
- Nonarteritic AION
- PION

10. •3. Hereditary: - Leber’s
- OA
•4. Nutritional and Toxic
•5. Compressive: - ON glioma
- ONS meningioma
- Thyroid
- Orbital SOL
•6. Traumatic

11. •7. Diabetic papillopathy
•8. Infiltrative: - sarcoid, syphilis,TB, fungal
- leukemia & lymphomas
- metastasis
- perioptic meningeal Ca
•9. Radiation optic neuropathy
•10.Glaucomatous

12. OPTIC NEURITIS
Ophthalmoscopic classification:
•1. Retrobulbar neuritis: MS common
•2. Papillitis: hyperaemia, oedema, disc
haemorrhage, common in children,
vitreous cells +
•3. Neuroretinitis: papillitis + retinitis &
macular star

13. DEMYELINATING OPTIC
NEURITIS
•1. Isolated ON
•2. MS with other ocular involvement, gaze
palsies, CN palsies, nystagmus
•3. Devic disease (neuromyelitis optica):
bilateral ON + transverse myelitis
•4. Schilder disease: <10years, generalised
progressive, bilateral ON, death within 1 to
2years

14. FEATURES
•Acute / subacute onset
•Young adults, 20 – 50 yrs (mean 30yrs)
•Females > males (3:1)
•Pain in / around the eye especially with
eye movement; photopsia
•Usually unilateral, m/b bilateral esp. in
children
•VA usually 6/18 – 6/60

15. •2/3 retrobulbar and 1/3 papillitis
•Features of ON dysfunction
•VFD: - central 30 degr. diffuse depression
- NF bundle defects
- central /centrocaecal scotomas
- altitudinal
•Uhthoff’s symptoms: exercise, hot shower

16. •Course: rapid VA decrease during 2/3 d,
stable level for 1-2 weeks, then recover
and returnig to normal within 2-3 months
•Prognosis: 75% recover VA to 6/9 or>
85% to 6/12 or >
1/3 recurrent attack within 5yrs
•Colour vision, CS, light brightness may
persist even if VA returns to normal

17. DIFFERENCIAL DIAGNOSIS
•Papillitis from AION; FFA helpful, disc
filling delay
•If atypical ON, d/d from compressive
lesion and other serious pathology
(infiltrative); MRI, CXR, FBC, ESR, CRP,
U+E, Glu, LFT, ACE, ANA, ANCA,
Syphilis serology, LHON, LP (CSF
analysis)
•Diagnosis of MS is supported by typical
white matter plaques on MRI and
oligoclonal bands in CSF

18. TREATMENT
•Majority do not require treatment
•IV Methylpred. Hastens visual recovery
but does not affect long-term outcome
•Indicated in pat. with poor vision in the
fellow eye or with severe pain and
occupational requirements

19. •Oral pred alone is contraindicated; no
affect on speed of recovery and assoc.
with higher recurrence rate
•IM interferon beta-1a reduces/delays the
development of clinical MS in pats. at high
risk ( >2 plaques on MRI )
•However, it is reserved for those who have
a second episode of clinical MS within the
last 2 years

20. REGIMEN
IV Methyl Pred
•1g IV daily for 3 days
•Followed by oral pred (1mg/kg/day) for 11
days and then tapered for 3 days

21. Association between ON & MS
•15-20% of MS pats. present with ON
•ON occurs in 50% of established MS pats.
•10-year risk of developing clinical MS after
an initial isolated attack of ON is:
- overall risk: 38%
- no MRI lesions: 22%
- one or more MRI lesions: 56% (MRI
findings are strongest predictor)

22. PARAINFECTIOUS OPTIC
NEURITIS
•ON m/b associated with:
- viral infections such as measles, mumps,
chicken pox, rubella, whooping cough &
glandular fever
- following immunisation
- direct involvement or delayed immune
response

23. •Presentation:- 1-3 weeks after viral infection
- severe bilateral visual loss
- headache, seizures, ataxia
•Signs:- frequently bilateral papillitis
- rarely neuroretinitis

24. Treatment
•Majority do not require treatment because
of spontaneus recovery
•IV steroids if visual loss severe & bilateral
or involves only seeing eye

25. INFECTIOUS OPTIC NEURITIS
•1. Sinus-related: unilateral, recurrent,
headache, spheno-ethmoidal sinusitis;
treated with systemic antibiotics and
surgical drainage
•2. Cat-scratch fever: neuroretinitis
•3. Syphilis: acute papillitis / neuroretinitis;
unilateral/bilateral, mild vitritis

26. •4. Lyme disease: spirochaetal infection,
neuroretinitis + other neurological s/s
•5. Cryptococcal meningitis: in AIDS
patients, uni/bilateral acute ON
•6. Varicella zoster: papillitis by spread
from contiguous retinitis

27. NON-INFECTIOUS OPTIC
NEURITIS
•Sarcoid: ON head may show characteristic
lumpy appearance, vitritis, steroids and/or
methotrexate
•Autoimmune; present as R/B neuritis or
AION, systemic steroids