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Optic atrophy (b)
1. BISMILLAHIR RAHMANIR RAHIM
Optic Atrophy
Chairperson: Prof. Dr. Syed Abul Kalam Azad
Presented by: Dr. Wahid Karim
DO Resident,
DMCH.
2. Definition
Optic atrophy refers to degeneration of the optic nerve,
which occurs as an end result of any pathologic process
that damages axons in the anterior visual system, i.e.,
from retinal ganglion cells to the lateral geniculate
body.
3. Types or Classification
It can be classified in several ways, including by
whether axonal death is initiated in the
retina(anterograde) or more centrally (retrograde),
and by cause. Optic ‘atrophy’ is not true atrophy, a
term that strictly refers to involutional change
secondary to lack of use. It is due to loss of vascularity
owing to obliteration of of the disc capillaries.
4. Types or classification
A. Aetiolgical: (i) Primary, (ii) Secondary, (iii) Consecutive.
B. Pathological: (i) Ascending: From optic nerve to brain. Ascending or
anterograde optic atrophy (Wallerian degeneration): Follows
damage to ganglion cells or nerve fibre layer due to diseases of the
retina or optic disc. In it the nerve fibre degeneration progresses
(ascends) from the eyeball towards the geniculation body. (ii)
Descending or retrograde optic atrophy: proceeds from the region
of the optic tract, chiasma or posterior portion of the optic nerve
towards the optic disc. Damage beyond lateral geniculate nucleus
(LGN), i.e., optic radiations and occipital cortex does not cause
optic atrophy as the second order neurons (axons of ganglion cells)
synapse in LGN.
C. Extent: (i) partial, (ii) Total.
D. Cliniclal/Ophthalmological: (i) Primary, (ii) secondary, (iii)
Cavernous or Glaucomatous, (iv) consecutive: It is ascending type.
5. Pathogenesis
The process consists of increased interstitial connective
tissues with atrophy & disappearance of some nerve
fibers & their myelin sheath.
6. Primary Optic atrophy
Primary optic atrophy occurs without antecedent swelling of
the optic nerve head. It may be caused by lesions affecting
the visual pathways at any point from the retrolaminar
portion of the optic nerve to the lateral geniculate body.
Lesions anterior to the optic chiasm result in unilateral optic
atrophy, whereas those involving the chiasm and optic tract
will cause bilateral changes.
Signs:
Flat chalky white disc with clearly delineated margins.
Reduction in the number of small blood vessels on the
disc surface.
Attenuation of peripapillary blood vessels and thinning of
the retinal nerve fibre layer (RNFL).
7. Stippling of Lamina Cribrosa.
The atrophy may be diffuse or sectoral depending on the cause and
level of the lesion. Temporal pallor of the optic nerve head may
indicate atrophy of fibres of the papillomacular bundle, and is
classically seen following demyelinating optic neuritis. Band atrophy
is a similar phenomenon caused by involvement of the fibres entering
the optic disc nasally and temporally; it occurs in lesions of the optic
chiasm or tract and gives nasal as well as temporal pallor.
Important causes
Optic neuritis.
Compression by tumours and aneurysms.
Hereditary optic neuropathies.
Toxic and nutritional optic neuropathies.
Trauma or hemorrhage.
Multiple sclerosis (most common cause).
Tabes dorsalis (classical cause).
Leber’s optic atrophy.
8. Secondary Optic Atrophy
Secondary optic atrophy is preceded by long-standing swelling of
the optic nerve head.
Signs vary according to the cause and its course.
Slightly or moderately raised dirty white or greyish disc with
poorly delineated margins due to gliosis. Optic disc is full of
connective tissues.
Obscuration of the lamina cribrosa.
Reduction in the number of small blood vessels on the disc
surface.
Peripapillary circumferential retinochoroidal folds, especially
temporal to the disc (Paton lines), sheathing of arterioles and
venous tortuosity may be present.
Causes include:
Chronic papilloedema,
Anterior ischaemic optic neuropathy.
Papillitis.
Neuro-retinis.
9. Consecutive optic atrophy
Consecutive optic atrophy is caused by disease of the
inner retina or its blood supply. The cause is usually
obvious on fundus examination. Causes are:
Extensive retinal photocoagulation,
Retinitis pigmentosa
Central retinal artery occlusion.
Diabetc Retinopathy.
Extensive Retino-choroiditis.
Pathological myopia etc.
10. Clinical Featurs
(i) Waxy pale of disc. (ii) Edge: Less Sharply formed.
(iii) Laminar dot sign in Lamina cribrosa. (iv) Cup:
Sometimes large optic cup. (v) Retinal blood vessels:
Markedly contracted, Chorioretinal changes occur.
11. Glaucomatous optic atroophy
It is specific for glaucoma:
I.Characterized by deep and wide cupping of optic disc
& nasal shifting of flood vessels. Pale colour of disc
Increased cup: Disc ratio.
II.Disappearance of optic nerve fibre layer with out
increasing connective tissue.
III.So that, large cavernous lacunae forms are found.
12. Fig. Optic atrophy. (A) Primary due to compression; (B) primary due to nutritional neuropathy – note
predominantly temporal pallor; (C) secondary due to chronic papilloedema – note prominent Paton
lines (D) consecutive due to vasculitis
14. Differences between clinical features of primary, secondary &
consecutive optic atrophies
Feature Primary Secondary Consecutive
APPEARANCE Chalky white Dirty grey white Waxy pallor
MARGINS Well defined Ill defined Well defined
LAMINA
CRIBROSA
Well seen Obscured Well seen
VESSELS Normal Peripapillary
sheathing
Attenuation
SURROUNDING
RETINA
Healthy Hyaline bodies/
drusen
Pathology seen
15. Total Optic atrophy
Clinical Features: (i) Pupil dilated, fixed, non-reacting
(Bilateral.
(ii) Consecutive consensual reaction exaggerated
(unilateral).
Vision: No perception of light (NPL).
16. Partial Optic atrophy
Clinical features:
(i)Vision: Reduced to counting finger (CF) 5';7'
(ii)Conscentric contraction of visual field with or without
scotoma. That means tubular vision.
Most forms of partial optic atrophy , involve a loss of
temporal fibres including the papillomacular bundles.
This results in ‘temporal pallor’. But this should be
confirmed by special investigations, since, temporal
side is normally pale, because the retinal vessels emerge
from the nasal side, and the temporal side is normally
less vascular.
17. Differential Diagnosis
Optic atrophy versus other causes of optic disc pallor:
• Pallor of optic disc in partial optic atrophy must be
differentiated from other causes of pallor disc which may be
non-pathological or pathological.
o Non-pathological pallor of optic disc: it is seen in
Axial myopia.
Infants.
Elderly people with sclerotic changes.
Temporal pallor is associated with large physiologic cup.
o Pathological pallor of optic disc other than optic atrophy: this
includes
Hypoplasia.
Congenital pit.
Coloboma.
18. Investigations:
• Field of vision: In partial optic atrophy, the central
vision is depressed with concentric contraction of the
visual field, according to the cause.
• Pupil may be semidilated & direct light reflex is very
sluggish or absent. Swinging flash light test depicts
Marcus Gun Pupil (RAPD).
• Fluorescein angiography of the optic nerve head.
• Visual Evoke response (VEK) is useful specially in
children.
• Total neurological evaluations like, X-ray of skull, CT
Scan, MRI of brain and optic nerve etc.
19. Treatment
Treatment of underlying cause may help in preserving
some vision in patients with partial optic atrophy.
However, once complete atrophy has set in, the vision
cannot be recovered.
Treatment is according to cause. However, high dose of
vitamin B1, B6, B12 is given. Hydroxocobalamine
(vitamin-B12) 1000 µg is administered for atrophy due to
toxic optic neuritis.
20. Miscellaneous hereditary optic atrophies
This heterogeneous group of rare disorders are
characterized primarily by bilateral optic atrophy. There
is no effective treatment, though some measures should
be taken.
Dominant optic atrophy (Kjer type optic atrophy,
optic atrophy type 1)
Inheritance is autosomal dominant (AD); this is the
most common hereditary optic atrophy with an
incidence of around 1 : 50 000; it is frequently due to a
mutation in the OPA1 gene on chromosome, which
causes mitochondrial dysfunction.
21. Presentation is typically, though not always, in
childhood with insidious visual loss. There is usually a
family history, but the course may be variable even
within the same family.
Optic atrophy may be subtle and temporal, or
diffuse. There may be enlargement of the cup.
Prognosis is variable (final VA 6/12–6/60) with
considerable differences within and between families.
Very slow progression over decades is typical.
Systemic abnormalities. Twenty per cent develop
sensorineural hearing loss; other features are less
common.
22. Behr syndrome
Inheritance is AR; heterozygotes may have mild
features.
Presentation is in early childhood with reduced
vision.
Optic atrophy is diffuse.
Prognosis is variable, with moderate to severe visual
loss and nystagmus.
Systemic abnormalities include spastic gait, ataxia
and mental handicap.
23. Wolfram syndrome
Wolfram syndrome is also referred to as DIDMOAD
(diabetes insipidus, diabetes mellitus, optic atrophy and
deafness).
Inheritance. Three genetic forms are recognized, caused
by a variety of mutations in WFS1, which gives Wolfram
syndrome 1, CISD2 – Wolfram syndrome 2 – and probably a
form caused by a mitochondrial DNA mutation, with
inheritance being AR, AD or via the maternal
mitochondrial line.
24. Presentation is usually between the ages of 5 and 21
years; diabetes mellitus is typically the first
manifestation, followed by visual problems.
Optic atrophy is diffuse and severe and may be
associated with disc cupping.
Prognosis is typically poor (final VA is <6/60).
Systemic abnormalities (apart from DIDMOAD) are
highly variable, presumably in part due to genetic
heterogeneity, and may include anosmia, ataxia,
seizures, mental handicap, short stature, endocrine
abnormalities and elevated CSF protein. Life
expectancy is usually substantially reduced.