Download MBBS Ophthalmology PPT 16 Optic Nerve Lecture Notes

Download MBBS (Bachelor of Medicine, Bachelor of Surgery) Ophthalmology PPT 16 Optic Nerve Lecture Notes


Optic Neuritis, Papil edema and Optic Atrophy

Department of Ophthalmology

Acknowledgement

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Yanoff and Duker. Papil edema. 2016 In: Ophthalmology. Mosby Inc.

?

Khurana AK. Optic atrophy 2014 In: Comprehensive Ophthalmology. CBS Publishers

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Weerasinghe, D., & Lueck, C.J. (2016). Mimics and chameleons of optic neuritis. Practical

neurology;16(2):96-110.

?

CME: Optic Neuritis: Diagnosis, Treatment, and Prognosis.

https://www.medscape.org/viewarticle/571660_2

?

Kahloun R et al. Infectious optic neuropathies: a clinical update. Eye and Brain 2015;7:59-81

?

Creel D. Visual y Evoked Potentials. 2012 Mar 1. In: Kolb H, Fernandez E, Nelson R, editors. Webvision:

The Organization of the Retina and Visual System [Internet]. Salt Lake City (UT): University of Utah

Health Sciences Center; 1995-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK107218/

?

Pastora-Salvador N et al. Foster Kennedy syndrome: papil edema in one eye with optic atrophy in the

other eye. CMAJ 2011;183(18):2135

?

Reynolds SA. Pinpointing Papil edema. Optometric Management 2015:82-4

https://www.optometricmanagement.com/issues/2015/september-2015/clinical-posterior

?

Schiffmann J et al. Evaluation and treatment of papil edema in pregnancy. Comprehensive ophthalmology

update 2006;7(4):187-202

?

Toosy AT. Optic Neuritis. Lancet Neurol. 2014 Jan;13(1):83-99

2


Learning Objectives

? At the end of the class, students shall be able to
? Define and classify optic neuritis.
? Understand the aetiology and principles of

management of optic neuritis.

? Understand the stages and importance of

papilloedema.

? Differentiate between various types of optic atrophy.

3

Normal optic disc

4


Question

? The disc in question is

of a 60 year old myope

who is instil ing timolol

eye drops since the past

5 years.


? Is this a normal optic

disc?

5

Optic Neuritis

Definition: Inflammation of the optic nerve,

impairing nerve conduction.
Secondary to demyelination, infection or

autoimmune pathology.

6


Classification

A. Papillitis
B. Retrobulbar neuritis

? Acute
? Chronic (toxic

amblyopia)

C. Neuroretinitis
D. Perineuritis

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Aetiology

? Idiopathic
? Demyelinating disorders

? Multiple Sclerosis

? Presenting feature in 25% patients
? 70% cases occur in established disease
? Recurs in same/ opposite eye in 25% patients
? Uhthoff"s phenomenon: impairment of vision more

with increased body temperature

? Pulfrich phenomenon: altered perception of moving

objects

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Aetiology

? Neuromyelitis optica (of Devic): acute, bilateral optic

neuritis in young patient with paraplegia

? Post-viral: mumps, measles, chicken pox, whooping

cough

? Metabolic/Nutritional deficiency:
B1, B6, B12, B2, Folic acid deficiency
Thyroid dysfunction, diabetes
? Hereditary optic neuritis (Leber's disease)

9

Aetiology

? Toxic amblyopia:
Chloroquine, Ethambutol
Tobacco, Ethyl alcohol, methyl alcohol
Lead, Arsenic.

? Ischaemic: Giant cel arteritis, Takayasu's disease,
PAN, SLE

? Granulomatous inflammation:
Sarcoidosis, tuberculosis, syphilis

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Symptoms

? Idiopathic/demyelinating : 20-40 years of age
? Viral: children
? Uniocular sudden/rapid diminution of vision
? Visual loss, usually maximum by end of second week,

improves by 1-4 weeks

? Discomfort/pain behind eyeball especially when moved

superiorly

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Signs

? Visual Acuity: Usually 6/60 or less
? Local tenderness
? Pupil ary reaction: Sluggish, ill-sustained or RAPD
? Impaired coloured vision: hue, brightness
? Impaired contrast sensitivity
? Delayed dark adaptation
? Visual Field: central, centrocaecal or paracentral

scotoma, more pronounced for coloured fields

12


Ophthalmoscopic findings

? Optic neuritis: MC in children,

engorged, oedematous optic disc

with obliteration of optic cup,

small haemorrhages on disc

? Retrobulbar neuritis: MC in

adults

? Neuroretinitis:
Optic neuritis+ macular star

13

Differential diagnosis

? Papilloedema
? Pseudopapillitis
High hypermetropia,
Myelinated nerve fibres,
Optic nerve head drusen
(blurred margin, disc not significantly
elevated, no vascular changes, stationary)

14


Investigations

? MRI: demyelinating

lesions, SOL

? VEP: reduced

amplitude and delayed

transmission time

(P100 latency

increased)

Right optic neuritis

15

16


Advanced case of optic neuritis

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Course and prognosis

? Recovery takes 4-6 weeks
? 90% recover normal VA, but colour vision

defects may persist

? No correlation between initial visual loss

and final visual outcome

? 10% secondary or post-neuritic optic

atrophy

? Better outcome in young, unilateral cases

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Treatment

? Of cause e.g. anti-infective therapy
? Intravenous methyl prednisolone 20

mg/kg/day(250 mg QID) for 3 consecutive days
followed by oral prednisolone 1-1.5 mg/kg

? Dexamethasone 200 mg OD pulse for 3-5 days

is a cheaper alternative

? Supportive therapy

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Papil oedema

? Definition: Bilateral, non-inflammatory

passive swelling of optic disc due to raised
Intracranial pressure.

? Does not develop if optic nerve is atrophic

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Foster-Kennedy syndrome : contralateral

papil oedema with ipsilateral pressure atrophy of

optic nerve
Due to - frontal lobe tumour, olfactory meningioma

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D/D: Causes of 'disc oedema'

? Papillitis, neuroretinitis
? Anterior Ischemic Optic Neuropathy
? Optic Nerve glioma, meningioma
? Central Retinal Venous Occlusion

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Aetio-Pathogenesis

? Elevated Intracranial pressure due to any cause
? Prelaminar Optic Nerve is affected by changes in tissue

pressure, IOP and CSF pressure

? Increased CSF pressure increases tissue pressure

hampering axoplasmic flow

? This further increases pressure on pre-laminar capillaries

and small veins causing vasodilatation and tortuosity

? Venous drainage compromise further increases

congestion

23

General Symptoms

? Headache, made worse by coughing or

straining

? Vomiting
? Focal neurological deficit with/without

changes in level of consciousness

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Ocular symptoms

? VA may be normal until late stages
? Amaurosis fugax in some
? In 25% patients, visual symptoms occur

only in severe, advanced papilloedema

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Signs

? Pupillary reactions are normal until

secondary atrophy sets in

? Early:

? Blurring of nasal>superior>inferior margins of

disc

? Disc hyperemia and dilated capil aries
? Spontaneous venous pulsation absent
? Splinter haemorrhages at/just off disc margin
? Normal optic cup preserved

26


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Established papilloedema

? Margins indistinct and cup

obliterated

? Surface elevated upto more

than +3 D with direct

ophthalmoscope

? Flame-shaped haemorrhages,

cotton-wool spots

? Venous engorgement and

peripapillary oedema

? Paton's Lines-radial lines

cascading from optic disc

? Macular star

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With progression

? Chronic papilloedema

? Central cup remains

obliterated

? Haemorrhagic and exudative

components resolve gradually

? 'Champagne cork' appearance

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? Atrophic papilloedema

? Retinal vessels attenuated

with perivascular sheathing

? Dirty white colour due to

reactive gliosis

? Leads to secondary optic

atrophy

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Visual fields

? Early-no changes
? Established stage- enlarged blind spot
? Chronic- peripheral constriction of field

with nerve fibre bundle defects

? Finally- total loss of visual field

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Fundus photo, FFA , OCT

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Papil oedema

Optic neuritis

History

Headache, vomiting

Rapid DV preceded by

fever/respiratory infection

Laterality

usually bilateral

usually unilateral

VA

normal till late stage

severely reduced <6/60

Pain/tenderness of eyeball

absent

may be present

Pupil reaction

normal

RAPD (Marcus-Gunn's pupil)

Disc swelling

>+3 D in established

+2D to +3D

Haemorrhage, exudates

More, in established

relatively less

Visual fields

Enlarged blind spot,

Central or centrocaecal scotoma

later gradual

constriction

Colour vision

No effect

Affected

CT/MRI

SOL

Demyelinating disorder

Recovery of vision

May not be complete Usually complete after adequat

33 e

even after treatment

treatment

Treatment

? Treat Cause
? Acetazolamide 250 mg 4 times a day
? Surgical decompression of optic nerve to

preserve vision

34


Optic Atrophy

? Definition: Degeneration of optic nerve

fibres with loss of their myelin sheaths
characterised by pallor of the optic disc
due to loss of vascularity owing to
obliteration of disc capillaries

35

Classification-Aetiological

Primary Optic Atrophy

? No local disturbance,

associated with CNS

disease or no discoverable

cause

? Commonest cause ?

Multiple Sclerosis

? Leber's optic atrophy
? Nerve compression:
Tumour, hydrocephalus
? Injury to retrobulbar optic

nerve

36


Cavernous type of Primary Optic

Atrophy

? Deep excavated

cup with

undermined

edges

? Glaucomatous

optic atrophy

37

Aetiological classification

? Secondary optic atrophy:

preceded by swelling of optic disc-
papilledema, optic neuritis, neuroretinitis

? Consecutive optic atrophy:

follows extensive disease of the retina -
Retinitis pigmentosa

Long-standing retinal detachment

38
Anatomical classification

? Ascending: Lesion in retina, terminates at

lateral geniculate body ?

? Eg: RP, CRAO
? Descending: Disease involving optic

nerve fibres anterior to LGB, terminates at
optic disc ?

? Eg: chiasmal compression

39



Symptoms

? Gradual/rapid loss of central/peripheral

vision

? Impairment of colour vision

40


Signs

? Visual Acuity impaired in proportion to

death of optic nerve fibres

? RAPD in unilateral Optic Atrophy
Ultimately pupil dilated and immobile

41

Primary OA ophthalmoscopy

? Pale disc, classically

paper white in colour

? Margins sharply defined
? Minimal atrophic

cupping

? Blood vessels

attenuated with marked

reduction of small blood

vessels on ONH to <6

42


Secondary OA ophthalmoscopy

? Pale disc with dirty-grey

colour, blurred margins

? Physiological cup is full,

lamina cribrosa obscured

? Narrowing of blood

vessels with sheathing

? Gliosis over disc surface

extending towards

peripapillary retina

43

Primary OA

Secondary OA

Appearance

chalky white

dirty grey

Margins

sharply defined

blurred

Cup

deep

obliterated

Laminar dots

visible

not visible

Glial proliferation

absent

marked

Vessels

no sheathing

sheathing

Previous disc oedema

absent

present

44


Consecutive optic atrophy

? Yellowish-waxy pallor of the disc
? Margins less sharply defined
? Marked narrowing, even obliteration of

retinal blood vessels

45

46
Investigations

? Visual field: In partial OA, central vision is

depressed with concentric contraction of
the visual field

? FFA of Optic nerve head
? VEP especially in children
? Neurological evaluation

47

Hereditary optic atrophy

? Autosomal recessive/dominant
? LHON: Leber's hereditary OA

48


Treatment

? Treat the cause
? Gene therapy is

emerging

? Community based

rehabilitation in

bilateral cases as

prognosis is poor

Low-vision aids

49

Question

? The adjoining

photograph belongs

to a 12 year old boy

who has difficulty in

seeing at night.

? Can you identify the

disc abnormality in

the photograph?

? What condition does

he suffer from?

50


Thank you

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This post was last modified on 07 April 2022