Neuro-Ophthalmology_Dr. Bastola.pptx

NEURO-OPHTHALMOLOGY
Dr. Pradeep Bastola, MD
Professor,
Department of Ophthalmology,
Chitwan Medical College Teaching Hospital,
Nepal
29 April 2022
Improving health worldwide
www.lshtm.ac.uk

References
• Walsh & Hoyt's Clinical Neuro-Ophthalmology, 6th Edition
• Adlers physiology of the eye 7th edition
• A.A.O. 2010-2011 section 5
• Ophthalmology 2nd volume: Myron and Yanoff
• Oxford text book of Ophthalmology
• Clinical ophthalmology By Jack J. kanski (Newer edition)
• A text book of Ophthalmology (Goldberg, Paymen)
• Various sources from Internet (Emedicine and articles)
• Wills Eye Manual
• Principles and Practice of Clinical Ophthalmology – 3rd edition

Important Terminologies
• Optic chiasma (Decussating point of Optic nerves)
• Optic tract (Formed by ipsilateral Temporal fibre and contralateral nasal fibre)
• Lateral geniculate body (Optic radiations or to pretectal nucleus)
• Pretectal nucleus: Get way to parasympathetic supply to Pupil
• Edinger Westphal nucleus
• Ciliary ganglion (Post ganglionic fibres to sphincter pupillae, IIIrd Nerve)
• Short ciliary nerves
• Anisocoira (Significant difference in pupil size in same person, 0.4mm
– 1mm)
• Corectopia: Abnormally placed pupil
• Polycoria: More than one aperture in the Iris of an eye
• Ectropion Pupillae: Everted puillary margin

Presentation layout
• Introduction/Anatomy – Optic nerve, visual pathway, and
defects
• Parasympathetic control of Pupillary size
–Light stimulus
• Parasympathetic control of Pupillary size
–Near point stimulus
• Sympathetic control of Pupillary size
• Abnormal Pupillary reactions
• Clinical Implications
• Optic disc pathologies

Visual field lesions and defects

Optic Nerve
• 2nd cranial nerve
• Sensory
• Starts from optic disc, extends to optic chiasma where two nerves meet.
• It is backwards continuation of retinal nerve fibers which consists of the axons
originating from the ganglion cells.
• It is not a peripheral nerve, but rather a white matter tract of central
nervous system.
• There are two optic nerves, each connecting the retina within each globe to
the target areas within the brain.

STRUCTURE OF NERVE
• 1.2 million myelinated fibers
• 53% crosses in optic chiasma
• Not a nerve in true sense- direct extension of brain
• Lacks neurilemma so unable to regenerate.
• Potential sub-arachnoid & subdural spaces.
• Macular fibers lie medially- assumes central position at optic foramen.

PARTS OF OPTIC NERVE
Total length:- 47-50 mm
• Intra-ocular part:- 1 mm
• Intra-orbital part:- 30 mm
• Intra-canalicular part:- 6-9 mm
• Intra-cranial part:- 10 mm

INTRA OCULAR PART
• Intraocular part passes through sclera(converting it into a sieve-like structure, the
lamina cribrosa), choroid and finally appears inside the eye as optic disc.
• Lamina cribrosa: The nerve fibres forming the optic nerve exit the eye Posteriorly
through a hole in the sclera that is occupied by a mesh-like structure called the
lamina cribrosa.
• It is formed by a multilayered network of collagen fibres that insert into the sclera
canal wall.
• The nerve fibers that comprise the optic nerve run through pores formed by these
collagen beams.

INTRAORBITAL PART
• Extends from back of eyeball to optic foramina.
• It is 30mm in length.
• The straight line distance from back of the globe to optic canal is much less, with
relative excess of the optic nerve being necessary for free movement of globe
during eye movement.
• Here it travels within the cone formed by 4 recti muscles near the optic foramina.
• So tumour with in the cone are common source of compression of optic nerve or
compressive optic neuropathy.
• In addition, enlargement of the muscles themselves particularly inferior. rectus,
med rectus. eg in grave’s Ophthalmopathy may compress the nerve.

Contd..
• Posteriorly, near the optic foramina, it is closely surrounded by the annulus of
Zinn and origin of 4 recti muscles.
• Some fibres of the superior rectus muscle are adherent to its sheath here, and
accounts for the painful ocular movements seen in retrobulbar neuritis.
• Anteriorly, the nerve is separated from the ocular muscles by the orbital fat.

Intaorbital part of optic nerve

INTRAORBITAL PART CONT……..
• Crossed superiorly by-
 Ophthalmic artery from lateral to medial side.
 Superior ophthalmic vein
 Nasocilliary nerve medial to lateral side.
• Crossed inferiorly by-
 Nerve to medial rectus
• At the apex - cilliary ganglion lie between optic nerve & lateral rectus.
• Near eye ball - there is retro ocular fat.

INTRACANALICULAR PART
• 6 to 9 mm in length.
• Closely related to ophthalmic artery- inferolaterally, covered in dura.
• Sphenoid & posterior ethmoid sinus lie medially and separated by thin bony lamina
which accounts for retrobulbar neuritis following sinus infection.
• Within the canal and immediately post to canal, meningeal tissue is adjacent to
optic nerve so benign tumour of meninges or meningioma are common causes of
compressive optic neuropathies in these location.

INTRACANALICULAR PART
• Closely related to ophthalmic artery- inferolaterally.
• Sphenoid & posterior ethmoid sinus lie medially
• Retrobulbar Optic neuritis following sinus infection.

INTRACRANIAL PART
• This part lies above cavernous sinus converge with the fellow nerve over
diaphragma sellae to form optic chiasma.
• There is highly variable length of nerve until optic chiasma is reached i.e. 8 to 9
mm

INTRACRANIAL PART AND OPTIC CHIASMA

OPTIC CHIASMA
• Chiasma (Crossroads)
• Here nasal fibres crosses and temporal at temporal are destined to remain
Ipsilateral.
• The percentage of the fibres that cross versus that do not is anatomically 53:47.
• Optic chiasma is flat & Quadrangular in shape
• 12mm (horizontally) and 8mm ( antero-posteriorly)
• Rest of tuberculum sellae & diaphragm sella.
• The latter is app. 10 mm between the inferior part of the nerve and sup. Part of the
pituitary so tumors of the pituitary which enlarges enough to compress chiasma
may cause compressive optic neuropathy.
• The chiasma is prefixed in(ant displaced) in app. 10%, post fixed in 75% of
subjects.

Although the optic nerve anatomically ends at the optic chiasma, the retinal ganglion axons
continue within the optic tract until lateral geniculate nucleus, superior colliculus, pretectal
nuclei or hypothalamus.

OPTIC TRACTS
• These are cylindrical bundles of nerve fibres running outwards and backwards
from the postero-lateral aspect of the optic chiasma.
• Each optic tract consists of fibres from the temporal half of the retina of the
same eye and the nasal half of the opposite eye.
• Posteriorly each optic tract ends in the lateral geniculate body.
• The pupillary reflex fibres pass onto pretectal nucleus in the midbrain
through the superior brachium.
• Some fibres terminate in the superior colliculus.

LATERAL GENICULATE BODIES
• These are oval structures situated at the posterior termination of the optic tracts.
• Each geniculate body consists of six layers of neurons (grey matter) alternating
with white matter (formed by optic fibres).
• The fibres of second-order neurons coming via optic tracts relay in these
neurons.

OPTIC RADIATION
• The fresh fibres from the lateral geniculate body form the geniculo- calcarine
tract(optic radiations) which ends in the visual area of the cerebral cortex, These
consist of the axons of third order.
VISUAL CORTEX
• It is located on the medial aspect of the occipital lobe, above and below the
calcarine fissure.
• It is subdivided in to the visual-sensory area (striate area 17) that receives the
fibres of the radiations, and the surrounding visual- psychic area (peristriate area
18 & parastriate area 19)

BLOOD SUPPLY OF OPTIC NERVE
• The visual pathway is mainly supplied by pial network of vessels except the orbital
part of optic nerve which is also supplied by an axial system derived from the
central artery of retina.
• The pial plexus around different parts of the visual pathway gets contribution from
different arteries.
 Visual pathway is supplied by-
Pial plexus
Calcarian artery
Posterior cerebral artery
Anterior choridal artery

Blood supply of visual pathway by pial plexus

Blood supply of the optic nerve head
• The surface layer of the optic disc is supplied by capillaries derived from the
retinal arterioles.
• The prelaminar region is mainly supplied by centripetal branches of the
peripapillary choroid with some contribution from the vessels of lamina cribrosa.
• The lamina cribrosa is supplied by branches from the posterior ciliary arteries and
arterial circle of Zinn.
• The retrolaminar part of the optic nerve is supplied by centrifugal branches from
central retinal artery and centripetal branches from pial plexus formed by branches
from the choroidal arteries, circle of Zinn, central retinal artery and ophthalmic
artery.

Visual Pathway
Visual pathway consists of
• Optic nerve
• Optic chiasma
• Optic tract
• Lateral geniculate bodies
• Optic radiation
• Visual cortex

Lesions of the visual pathway and corresponding visual field defects
1. Optic nerve (Monocular blindness-Ipsilateral)
2.Proximal part of optic nerve (Monocular blindness and contralateral
temporal hemianopia)
3.Central chiasma (Heteronymous-Bitemporal hemianopia)
4.Lateral chiasma (Binasal hemianopsia)
5.Optic tract (Homonymous hemianopsia) 6.Geniculate body
(Homonymous hemianopsia)
7.Part of optic radiations in temporal
lobe (Left upper quadrantanopsia-Both eye pie in the sky
phenomenon-Meyer’s loop)
8.Part of optic radiations in parietal lobe
(Left inferior quadrantanopsia-Both eye pie in the floor -Baum’s
loop)
9.Optic radiations (Homonymous hemianopsia)
10.Visual cortex sparing the macula (Homonymous hemianopsia
with macula sparing)
11.Visual cortex, only macula (Homonymous macular involving
visual field defect)

Normal Pupil
1. Round, Regular: 3 - 4 mm in size (2- 5 mm reported)
2. Myopic eyes: Larger pupil (Room condition)
3. Hypermetropic eyes: Smaller pupil (Room condition)
4. Smaller in infants : dilator muscle not well developed
5. Large in Adolescent : sympathetic over action
6. Small in old age : Fibrotic sphincter
7. Premature baby has no pupillary light reaction until 31 weeks of gestation
8. Small during sleep
• Sympathetic activity reduced
• Parasympathetic activity enhanced

Oculomotor Nerve (III cranial Nerve)

Why do we need to know about oculomotor
nerve?
• The origin, pathway and distribution is diverse and important and helps to localize
the exact location of lesion and type of pathology
• Diabetic microangiopathy can be differentiated from tumors.
• As it originates in midbrain, the signs in midbrain lesion can be diagnosed and thus
life threatening situations can be treated adequately and in time.
• Complete and partial third nerve palsies can occur and thus help in prognosis of
disease.

• Components of third nerve
• Origin
• Course
• Important locations
• Termination and supply
• Lesions of third nerve, depending on location
• Complete third nerve palsy
• Partial third nerve palsy
• Pupil sparing third nerve palsy

COMPONENTS OF OCULOMOTOR NERVE
• Main motor nucleus-
• Somatic motor – GENERAL SOMATIC EFFERENT- supplies 4 EXTRAOCULAR MUSCLES
and levator palpebrae superioris (LPS)-
• Function - Eye movements
• Accessory parasympathetic nucleus - EDINGER WESTPHAL NUCLEUS
• Supplies Constrictor pupillae muscle and ciliary muscles
• Function- Constricts pupil and accommodates eyes
SO4, LR6 ALL OTHERS 3

ORIGIN
• Arises from the main motor nucleus located at the
ventromedial mid brain in the grey matter surrounding
the cerebral aqueduct at the level of superior colliculus.
• Outgoing nerve fibers pass anteriorly through the red
nucleus and emerge on the anterior surface of the
midbrain.
• LPS of both sides is supplied by a single central group of
cells- central caudal nucleus
• Superior rectus muscle is supplied by contralateral
oculomotor nucleus
• Remaining muscles are supplied Ipsilateral.

Summary
FIBERS FROM TO
UNCROSSED FIBERS IPSILATERAL OCULOMOTOR NUCLEUS MEDIAL RECTUS
INFERIOR RECTUS
INFERIOR OBLIQUE
CROSSED FIBERS CONTRALATERAL OCULOMOTOR
NUCLEUS
SUPERIOR RECTUS
CROSSED AND UNCROSSED FIBERS BOTH OCULOMOTOR NUCLEI LEVATOR PALPEBRAE SUPERIORIS
UNCROSSED PARASYMPATHETIC FIBERS IPSILATERAL EDINGER WESTPHAL
NUCLEI
CONSTRICTOR PUPILLAE MUSCLE
CILIARY MUSCLE

Main motor nucleus - inputs
• Corticonuclear fibers from both cerebral hemispheres
• Tectobulbar fibers from superior colliculus
• Fibers from medial longitudinal fasciculus- connected to nuclei of
fourth, sixth and eighth cranial nerves

EDINGER WESTPHAL NUCLEUS
• Accessory parasympathetic nucleus
• Posterior to main oculomotor nucleus
• Axons accompany oculomotor fibers from main nucleus and synapse in ciliary
ganglion. Postganglionic fibers pass through short ciliary nerves to the
constrictor pupillae of iris and ciliary muscle.
• Receive corticonuclear fibers for accommodation reflex and fibers from
pretectal nucleus for direct and consensual light refexes.

Course • Emerges from anterior aspect of midbrain medial to cerebral
peduncle.
• Lies within subarachnoid space, passes between posterior cerebral
and superior cerebellar arteries and runs forward lateral and parallel
to posterior communicating artery.
• As it runs forwards, it pierces the arachnoid and lies between the
fixed and free borders of tentorium cerebri.
• It later pierces the dura and lies in the lateral wall of the cavernous
sinus just above the CN IV.
• At the anterior end of cavernous sinus, it divides into 2 divisions a
small superior division and a larger inferior division which enter the
orbit through the superior orbital fissure within the tendinous ring.

Divisions and Supply
• Superior division- superior rectus and levator palpebrae superioris
• Inferior division-3 branches-medial and inferior recti and inferior oblique muscles.
• Nerve to the inferior oblique muscle gives rise to a short, thick branch which passes
to the ciliary ganglion- this branch contains parasympathetic fibers to ciliary
ganglion.

Course
1. Nucleus
2. Central segment
3. Cisternal segment
4. Cavernous segment
5. Orbital segment

III Nerve palsy
Types:
• Complete
• Incomplete
• Divisional

Features of III Nerve palsy
1) Ptosis - paralysis of LPS muscle
2) Deviation - outward, downward (ABDUCTION) and intorted - unopposed action of LR and
SO. INTORTION INCREASES ON ATTEMPTED DOWNGAZE.
3) Fixed dilated pupil - paralysis of sphincter pupillae muscle
4) Defective accommodation - paralysis of ciliary muscle
5) Crossed diplopia - paralytic divergent squint
6) Head posture - head takes posture consistent with actions of paralyzed muscles.i.e.
head is turned on the opposite side, tilted towards the same side and chin is slightly
raised.
LIMITED ADDUCTION, ABDUCTION, DEPRESSION

Important notes
PUPILLOMOTOR FIBERS:
Parasympathetic
located superficially between the
brainstem and cavernous sinus
Blood supply derived from pial blood
vessels.
Main trunk of 3rd nerve supplied by vasa
vasorum

Clinical case
84 years female presented to the emergency ward with the chief
complaints of:
1) Drooping of right eyelid since 1 day
2) Dizziness since 1 day
• The patient was a known case of HTN since 5 years, was under
medication with losartan 50 mg and amlodipine 5 mg daily. However, she
did not take her medications daily.
On examination

• There was drooping of the right eyelid, without any signs of voluntary
movement of the lid. The left eyelid was voluntary.
• Only the adduction was present in the right eyelid and binocular
movements of the right eyelid were absent, while both uniocular and
binocular movements of the left eyelid was preserved

CISTERNAL SEGMENT LESION - LYMPHOMA

RIGHT CAROTID CAVERNOUS FISTULA WITH III, IV CRANIAL NERVE PALSY

Orbital segment lesions
• Lesions of orbital segment at orbital apex cause combined 3,4 and 6th
nerve palsies, almost similar to cavernous segment lesions.

• Nuclear
• Vascular- diabetes, hypertension
• Neoplastic- primary tumor or metastatic
• Haemorrhage
• Fascicular
• Vascular- diabetes, hypertension
• Neoplastic- primary tumor or metastatic
• Hemorrhage
• Demyelination
• Basilar causes: isolated 3rd nerve palsy
• Head trauma: extradural/subdural hemorrhage
• Aneurysm

Summary
• Intra-cavernous causes: 4th,6th nerve and V1 affected
• Diabetes: pupil sparing 3rd nerve palsy
• Pituitary apoplexy
• Others- aneurysm, meningioma, carotid cavernous fistula
• Intraorbital causes:
• Trauma
• Vascular
• Neoplasm
• Inflammation

3RD NERVE PALSY: INVESTIGATONS
INVESTIGATIONS FOR 3RD NERVE PALSY
<50 YEARS CT/ MRI, CEREBRAL
ANGIOGRAPHY
>50 YEARS
PUPIL SPARING FBS AND PPBS,HbA1C,
LIPID PROFILE, BP, CBC
WITH ESR, CRP
PUPIL INVOLVING FBS,PPBS, HbA1C,LIPID
PROFILE,BP, CBC WITH
ESR, CRP, CT/MRI,
CEREBRAL
ANGIOGRAPHY

D/D OF 3RD CRANIAL NERVE PALSY
• Myasthenia gravis
• Thyroid associated orbitopathy
• Chronic progressive external Ophthalmoplegia
• Idiopathic orbital inflammatory disease

Treatment (Medical)
• Non-surgical
• Treatment of underlying cause
• Diplopia – Occlusion patch or prism in involved eye
• Monitor children for development of amblyopia
Treatment (Surgical)
• Neurosurgery – Aneurysm or hematoma
• Strabismus or ptosis surgery – Not earlier than 6 months from time of
onset

Light Stimulus
Optic Nerve
Optic Tract Pretectal Nucleus
(Synapse) Ciliary ganglion
Short Ciliary Nerves
Sphincter
Pupillae
Constriction of Pupil.
Parasympathetic Control of Pupillary Size
Optic Chiasm
(Nasal fibres cross
to opposite side)
III Cranial Nerve
of Both Sides
Edinger Westphal
Nucleus of both sides

Where does the impulse begin?
• Begins in the retina with the photoreceptors
• No separate receptors for visual and pupillary
fibers

Contd….
• Ganglion cells
–First order neuron
–Melanopsin containing ganglion cells – major
contributor in the midbrain serving the
classic pupillary light reflex pathway
.

Melanopsin containing ganglion cells..???
a. Photosensitive, with a broad spectral
peak centering on about 490 nm
b. Project to the suprachiasmatic
nucleus in the hypothalamus and to
the pretectal nucleus
c. Provide light sensing information to
the hypothalamus
-modulate the circadian rhythm

Inter neurons of light reflex
Optic nerve
Optic chiasma
Nasal fibres crosses so that one optic tract serving for
homonymous field
Optic tract
Pretectal nucleus
Edinger-Westphal nuclei
Bilateral and equal
innervations
Ganglion cell fibers destined for the pretectal region of the mesencephalon
leave the optic tracts before reaching the LGN.

The efferent arc of the pupillary light reflex
Visceral oculomotor nuclei
2. Anterior median nuclei primary neurons
involved in accommodation
3. Nucleus of Perlia
1. Edinger-Westphal
nuclei neurons serving
for pupillary light reflex

Pupillary Fibers in the Oculomotor Nerve
Saggital reconstruction of brain
stem with course of third nerve
1. Emergence from brain stem
2. Mid point in sub arachnoid space
3. Where third nerve enters the dura
4. At anterior cavernous sinus where
third nerve divides

Ciliary Ganglion and Short Ciliary Nerves
• Site of the synapse with the preganglionic
parasympathetic fibers
• 2 mm X 1 mm
• 1 cm anterior to the medial end of the
superior orbital fissure
• E W nucleus
• 3rd nerve
• Branch to inferior oblique
• Ciliary ganglion
• Short ciliary nerves

Contd….
• Parasympathetic ganglia
• About 3-5% supply the iris sphincter
(Sphincter pupillae)
• About 95-97% ciliary muscle

Ciliary Ganglion and Short Ciliary Nerves
contd…
8 to 20 short ciliary nerves leave ciliary ganglion in
two or three bundles
1. Postganglionic, parasympathetic
fibers ( synapse over there)
2. Postganglionic, sympathetic
vasomotor
3. Afferent sensory fibers of the
trigeminal nerve

Retina
Optic Nerve
Optic
Chiasma
Optic Tract
Lateral Geniculate
body
Optic Radiation
Occipital Cortex
Frontal Lobe (undetermined
pathway)
Edinger Westphal Nucleus
(undetermined pathway)
Ciliary Ganglion III Nerve
Short ciliary
nerve
Sphincter
Pupillae
Parasympathetic Control of pupillary Size
Near Point Stimulus – Controversial Pathway:

Near Reflex
• Two components:
–Convergence Reflex
–Accommodation Reflex
• Triad of Synkinetic Near
Response:
–Convergence
–Accommodation of lens
–Constriction of pupil

Near Reflex
• Pathway for near reflex is more
ventrally located than that for light
reflex
• Anatomical basis for some instances
of light-near dissociation of the pupils

Sympathetic Outflow Pathway
• Final common path of active dilator impulses extends from the hypothalamus to
the iris.
• Long three-neuron arc
–Hypothalamus to the lateral cervical cord
–Spinal cord to superior cervical ganglion
–Superior cervical ganglion to the orbit and iris

Contd…
• Uncrossed and lateral position in the brain stem
• Ciliospinal center of Budge and Waller in anterolateral
columns
• Synapse with the preganglionic neurons at C8 to T2.
• Preganglionic Sympathetic Fibers proceed close to the
pleura at the apex of the lung

7. s c g 8 i c a 9, e c a 10, sudomotor fibers to face; 11, carotid plexus; 12, caroticotympanic nerve; 13,
tympanic plexus; 14, deep petrosal nerve; 15, lesser superficial petrosal nerve; 16, sympathetic contribution
to vidian nerve; 17, ophthalmic division of the trigeminal nerve; 18, nasociliary nerve; 19, long ciliary nerve;
20, ciliary muscle and iris dilator muscle; 21, probable pathway of sympathetic contribution to retractor
muscles of the eyelids; 22, vasomotor and some sudomotor fibers; 23, o a 24, lacrimal gland; 25, short ciliary
nerves; 26, salivary glands; 27, greater superficial petrosal nerve

Posterior
Hypothalamus
Brain Stem
Cranial Spinal Cord
Synapse at C8T1-2
Superior cervical
ganglion synapse Along internal carotid artery
Cavernous sinus
6th Nerve(briefly)
5th C.N. (Ophthalmic)
Nasociliary branch
Ciliary ganglion (No
synapse)
Long ciliary nerve
Dilator pupillae
Sympathetic Control of Pupillary Size

Supranuclear influences
Excitatory influence in the visceral nuclei of the oculomotor complex
1. Arrives via centrifugal pathways from the occipital cortex
2.Pupil constriction to near stimuli
3.Distributed ventrolaterally in the upper midbrain
4.Mainly to the anterior median nucleus : near reflex
Light near dissociation
in isolated lesion of pretectal region

Other pupillary reflexes
• Darkness reflex
–abolition of light reflex, contraction of dilator pupillae
• Psycho sensory reflex
–cortical reflex
–loud noise or pain causes pupillary dilatation
• Lid closure reflex
–constriction of pupil with blinking

Abnormal Pupillary Reactions
• Afferent pupillary conduction defects
• Efferent pupillary defects
• Pupillary light near dissociation
• Anisocoira
D/D: Essential anisocoria, Adie pupil (long-standing), Argyll-Robertson pupil, Chronic
anterior uveitis, Pupillary sphincter tear
Unilateral use of miotics or mydriatics
Third nerve palsy
Ptosis:
Aponeurotic ptosis Ocular myasthenia
Third nerve palsy (ptotic eye has the larger pupil) Congenital ptosis

Afferent Pupillary Conduction Defects
Total Afferent Pupillary Defect
(TAPD)
Amaurotic Pupil
Complete optic nerve lesion
Relative Afferent Pupillary Defect
(RAPD)
Incomplete optic nerve lesion
Severe retinal disease
Extensive Amblyopia
Wernicke’s Hemianopic Pupil
Midline optic chiasma lesion
Optic tract lesions

• RAPD is an objective sign of unilateral or asymmetric
disease of the optic nerve head or retina mostly.
Grading Scale: RAPD
Grade 0: No reaction
Grade 1+: A weak initial pupillary constriction followed by
greater redilation
Grade 2+: An initial pupillary stall followed by greater
redilation Grade 3+: An immediate pupillary dilation
Grade 4+: No reaction to light – Amaurotic pupil

Causes of RAPD
• Optic Nerve Disorders
–Unilateral or asymmetric bilateral optic neuropathy
• Retinal Disease
–Presence of a RAPD usually indicates macular involvement
• Dense amblyopia (Amblyopia is defined as diminution of vision usually in
one eye without any known organic cause)
–A small RAPD
• Media Opacities
–Dense vitreous hemorrhage

• Optic Tract Disorders
–a small to moderate RAPD in the contralateral eye
• Pretectal Nucleus lesion
–A unilateral lesion in the pretectal nucleus
–Contralateral RAPD without any visual field defect

Efferent Pupillary Defects
• Absence of direct and consensual
light reflex on the affected side
• Presence of direct and consensual
light reflex on the normal side

• On the affected side, near reflex is
absent
• Pupil - dilated and fixed
• Alarming to a physician - Oculomotor
nerve palsy must be ruled out

Light near dissociation of pupil
• Better pupillary response to near than to light
• Causes
–Lesions of retina eg RD
– Lesions of Optic nerve tract
–Midbrain lesion in pretectal area
–Argyll Robertson pupil

Anisocoria
• Difference in the size of two pupils is more than 0.4
mm
• 20% of the general population below 18 years
• Prevalence rises to 33% persons over 60 years

Contd..
Physiologic anisocoria
–Most common cause of anisocoria
–41% have anisocoria of 0.4mm or more when observed for 5 days
–19% have anisocoria at any given time
–20% have less than 1mm difference
Anisocoria equal in dim and bright light
–Consistent with physiologic anisocoria

Contd….
• Anisocoria greater in dim light
–Posterior synchiae
–Pharmacologic anisocoria - miotic
–Physiologic anisocoria
• Dilate normally after cocaine installation without dilatation lag
–Horner syndrome

Horner syndrome (Anisocoria, anophthalmos, anhydrosis)
• Any lesion in the oculosympathetic pathway
results in Horner syndrome

• Ipsilateral ptosis,miosis and
anhydrosis
• Other features
– anisocoria,
–dilatation lag
–herterochromia iridis
–increased accommodation in the
affected side

Causes
• First-order neuron lesions
–Arnold-Chiari malformation
–Cerebral vascular accident
–Demyelinating disease
–Intrapontine hemorrhage
–Pituitary tumor
–Syringomyelia

2nd -order neuron lesions
Pancoast tumor
Birth trauma with injury to lower
brachial plexus
Cervical rib
Aneurysm/dissection of aorta
Neuroblastoma
Trauma/surgical injury
3rd -order neuron lesions
Internal carotid artery dissection
Carotid cavernous fistula
Cluster/migraine headaches
Herpes zoster

• Few tests to confirm Horner's syndrome & in identifying the level of
damage
–Dilation lag
–Cocaine test:
• 2 drops of 10% cocaine – dilates the normal pupil
–1% Hydroxyamphetamine test:
• Differentiation between pre – ganglionic & post - ganglionic Horner's
syndrome
• anisocoria increases in post - ganglionic type

Anisocoria
Anisocoria greater in bright light
Iris damage(sphincter damage)
Pharmalogic dilatation
Adies tonic pupil
Third nerve palsy

Adies Tonic Pupil
• Sluggish segmental pupillary response to light
• Better response to near effort followed by slow redilatation
• Caused by post ganglionic parasympathetic damage

Adies tonic pupil contd……
• Supersensitive to parasympathomimetics
• Due to denervation hypersupersensitivity
• Histopathologically - reduction in the number of ganglion cells
in the ciliary ganglion

Third Nerve Palsy
Pupillary involvement is almost always accompanied by ptosis and limitation of
extraocular mobility
Maximum anisocoria occurs in bright light
Aneurysms at the junction of internal carotid and posterior communicating artery
must be excluded
If pupil is spared aneurysm is unlikely
Causes
Basal aneurysm
Supratentrorial SOL
Basal meningitis
Ischaemic oculomotor palsy (DM), Vasculitis

Argyll Robertson Pupil (ARP)
–Occurs in neurosyphilis
–Affected pupil are small(less than 2 mm), regular
–Do not react to light but near reaction is normal
–Even mioticpupil reacts briskly to near stimuli
Mnemonic:
ARP: Accommodation Reflex Present PRA: Pupillary reflex absent

Hutchinson’s pupil
–Comatosed patient with unilateral dilated poorly reacting pupil (Young
adult/Elderly giving history of heavy alcohol intake and fall in the bathroom or
toilet in the morning)
–Suggestive of ipsilateral expanding intracranial supratentorial mass (hematoma)
“Neurosurgical Emergency if not diagnosed in time patient can die due to
extensive subdural hematoma”

Pourfour Du Petit Syndrome (Opposite Horner Syndrome)
• Rare dysautonomic complication due to brachial
plexus block
• Mydriasis, eyelid retraction, and hyperhydrosis.
• PDPs was first described by Francois Pourfour Du
Petit (1664 - 1741), a French physician.
• Signs of increased sympathetic activity in the eyes
and upper extremity following slashed wound of
neck with sword.

Flow chart to evaluate anisocoria

Disc edema:
Swelling of optic disc due to any cause (active or passive swelling )
Papilloedema:
Swelling of the optic disc that is secondary to increase intracranial pressure
Exception: Grade IV Hypertensive retinopathy

1. Parsons - 1908 firstapplied the term papilledema to optic disc swelling associated with
increased ICP
2. In 1911 Paton & Holmes made 1st detailed morphologic studies of disc swelling & provided
definitive description of non inflammatory passive edema with normal V/A encountered in
patients with increased ICP
3. Hayreh & Hayreh used stereoscopic color photography & fluorescein angiography to study
experimentally produced papilledema in monkeys

Causes of disc edema
• Inflammatory
- Papillitis, Neuroretintis, Papillophlebitis
• Vascular
- AION, CRVO, HTN
• Compressive
-Optic nerve sheath meningioma, glioma, cysts,
-Retrobulbar mass, orbital tumours
• Infiltrative
-Sarcoidosis, Lymphoma, metastatic tumours, leukemia

• Infective
- Orbital cellulitis
• Traumatic
- Traumatic optic neuropathy
• Toxic
- Methanol poisoning, drugs
• Metabolic
- Dysthyroidism, diabetes, proliferative retinopathies
• Systemic disease
- Anemia, hypoxemia, hypertension, uremia
• Ocular disease
- Uveitis, hypotony

Pathophysiology
• Two types of axonal transport
1.orthrograde ----fast and slow component
2.retrograde
• Blockage of fast component of orthrograde flow is responsible for
optic disc swelling
• Edema results from disturbance of the pressure gradient across the
lamina cribrosa.
• Disc edema involves only that part of optic nerve anterior to lamina
cribrosa

Nerve diseases that can cause optic neuritis (ON)
 multiple sclerosis
 neuromyelitis optica (Devic’s disease): Young age, Optic neuritis, poor prognosis
 Schilder’s disease: Rare demyelinating disease (myelinoclastic diffuse sclerosis)
 Infections that may cause ON include: Mumps, measles, tuberculosis, Lyme
disease

Other causes of ON include;
• Sarcoidosis: an illness that causes inflammation in various organs
and tissues
• Guillain-Barre syndrome: a disease in which your immune system
attacks your nervous system
• Post-vaccination reaction: an immune response following vaccinations
Uhthoff’s phenomenon: eye vision worsens with increase in body temperature
Pulrich phenomenon: a pendulum swinging in one plane appears to trace an ellipse
because optic nerve conduction velocity is not symmetrical

Unilateral causes of disc edema
• Papillitis/ optic neuritis
• AION
• Orbital tumours
• Papillophlebitis
• CRVO
• Ocular hypotony
• Infiltrative disorders
• Foster Kennedy Syndrome
• Pseudo Foster Kennedy
Syndrome
Bilateral causes of disc edema
• Raised ICP: Papilloedema
• HTN
• Diabetic papillopathy
• Advanced Grave’s disease or Dysthyroid eye
disease
• Cavernous sinus thrombosis
• Carotid-cavernous fistula
• Leber hereditary optic neuropathy- acute
stage
• Anemia, hypoxaemia

Signs of optic disc edema
• Mechanical signs
• Elevation of the optic nerve head
• Blurring of the margins
• Filling in of the cup
• Edema of the peripapillary nerve fiber layer
• Retinal and /or choroidal folds
• Vascular signs
• Hyperemia of the disc
• Venous dilation and tortuosity
• Peripapillary hemorrhages
• Exudates in the disc or peripapillary area
• Nerve fiber layer infarcts

PAPILLOEDEMA
2. Classification of Papilloedema
• Early
• Established (acute)
• Longstanding (chronic)
• Atrophic (secondary optic atrophy)
1. Introduction
• Circulation of cerebrospinal fluid
• Causes of raised intracranial pressure
• Hydrocephalus

(a) Subarachnoid
space
Circulation of cerebrospinal fluid
(b) Lateral
ventricle
Foramen of
Monro
(c) Third
ventricle
Sylvius
aqueduct
(d) Fourth ventricle
Foramen of
Magendie
and Luschka
a
b
c
e
d
(e) Reabsorption in to
venous sinus blood
via arachnoid
granulations

Causes of Raised Intracranial Pressure
1. Space-occupying lesions
2. Blockage of ventricular system
3. Obstruction of CSF absorption
4. Benign intracranial hypertension (pseudotumour
cerebri)
5. Diffuse cerebral oedema
6. Hypersecretion of CSF

Hydrocephalus
Dilated cerebral ventricles
Communicating - obstruction to CSF flow in basilar cisterns or cerebral
subarachnoid space
Non-communicating - obstruction to CSF flow in ventricular system or at
exit of foramina of fourth ventricle

Early Papilloedema
• VA - normal
• Mild disc hyperemia
• Indistinct disc margins - initially nasal
• Mild venous engorgement
• Normal optic cup
• Spontaneous venous pulsation - absent (only present
in 20% of normals)

Established Papilloedema (acute)
• VA - usually normal
• Severe disc elevation and hyperaemia
• Very indistinct disc margins
• Obscuration of small vessels on disc
• Marked venous engorgement
• Reduced or absent optic cup
• Haemorrhages + cotton-wool spots
• Macular star

Longstanding Papilloedema (chronic)
• VA - variable
• Marked disc elevation but less hyperaemia
• Disc margins - indistinct
• Variable venous engorgement
• Absent optic cup

Atrophic Papilloedema (secondary optic atrophy)
• VA - severely decreased
• Mild disc elevation
• Indistinct disc margins
• Disc pallor with few crossing vessels

Pathology
• Blockage of axoplasmic transport
• Axonal transport along ganglion cell axons that form optic nerve occurs in
orthograde and retrograde direction
• Axonal blockage usually occurs at the level of lamina choroidalis or lamina
scleralis
• Clinically, disc edema produced by any event that increases venous pressure at
or near lamina cribrosa or that mechanically or physiologically directly blocks
axoplasmic flow

OPTIC NEUROPATHIES
1. Clinical features
2. Special investigations
3. Optic neuritis
Retrobulbar neuritis: Inflammation of the optic nerve in retrobulbar region
Papillitis: Inflammation of the Optic disc
Neuroretintis: Inflammation of the Optic disc and retina simultaneously
• Anterior ischaemic optic neuropathy (AION)
• Leber hereditary optic neuropathy

Signs of optic nerve dysfunction
• Reduced visual acuity
• Afferent pupillary conduction defect
• Dyschromatopsia
• Diminished light brightness
sensitivity

Special investigations
Orbital fat-suppression techniques
in T1-weighted images Assessment of electrical activity of
visual cortex created by retinal
stimulation
MRI Visually evokedpotential

Classification of optic neuritis
Retrobulbar neuritis (normal
disc)
Papillitis (hyperaemia and
oedema)
• Demyelination - most common•
• Sinus-related (ethmoiditis)
• Lyme disease
Viral infections and immunization in
children (bilateral)
Demyelination (uncommon)
Syphilis
Neuroretinitis (papillitis and macular
star)
• Cat-scratch fever
• Lyme disease
• Syphilis

Non-arteritic AION
• Pale disc with diffuse or sectorial
oedema
Resolution of oedema and
haemorrhage
• Few, small splinter-shaped haemorrhages •
Optic atrophy and variable visual
loss
Presentation
• Age - 45-65 years
• Altitudinal field defect
• Eventually bilateral in 30% (give aspirin)

FA in acute non-arteritic AION
Generalized hyperfluorescence
Increasing localized
hyperfluorescence
Localized hyperfluorescence

Superficial temporal arteritis (Giant Cell Arteritis)
Presentation
• Age - 65-80 years
• Scalp tenderness
• Headache
• Jaw claudication
• Polymyalgia rheumatica
• Superficial temporal arteritis
• Acute visual loss
Special investigations
• ESR - often > 60, but normal in 20%
• C-reactive protein - always raised
• Temporal artery biopsy

Histology of giant cell arteritis
• High-magnification shows giant cells
• Granulomatous cell infiltration
• Disruption of internal elastic lamina
• Proliferation of intima
• Occlusion of lumen

Arteritic AION
• Affects about 25% of untreated patients with giant cell
arteritis
• Severe acute visual loss
• Treatment - steroids to protect fellow eye
• Bilateral in 65% if untreated
• Pale disc with diffuse oedema
• Few, small splinter-shaped haemorrhages
• Subsequent optic atrophy

Leber hereditary optic neuropathy
Maternal mitochondrial DNA mutations Presents
• Typically in males - third decade
• Occasionally in females - any age
• Initially unilateral visual loss
• Fellow eye involved within 2 months
• Bilateral optic atrophy
Signs
• Disc hyperaemia and dilated capillaries (telangiectatic
microangiopathy)
• Vascular tortuosity
• Swelling of peripapillary nerve fibre layer
Subsequent bilateral optic atrophy

Features Papilloedema Papillitis Pseudopapillitis
Laterality Usually B/L Usually U/L May be U/L
VA Transient attacks of blurred
vision
Sudden marked loss of
vision
Depends upon degree
of optic atrophy
Pain and
tenderness
Absent Present Absent
Media Clear Post.Vit haze Clear

Features Papilloedema Papillitis Pseudopapillitis
Disc margin Blurred Blurred Not well defined
Disc swelling 2-6D Not >3 D Depends on
degree of
hyperopia
Peripapillary
oedema
Present Present Absent
Venous
engorgement
More marked Less marked Not present
Retinal hge Marked Usually not
present
Absent
Retinal exudate More marked Less marked Absent

Macula Macular Star may be
present
Absent
Fields Enlarged blind
spot
Central scotoma
more with color
object
No defect
FFA Late leakage of
dye
Minimal leakage No leakage of dye

OPTIC ATROPHY
It is a term usually applied to the condition of the optic disc when the optic nerve is
degenerated.
Etiology:
• Syphilis – Tabes dorsalis
• Pressure – pituitary tumor, glioma of optic nerve
• Tuberculous meningitis.
• Glaucomatous optic atrophy
• Circulatory optic atrophy – due to occlusion of central rétinal artery, arterio- sclerosis.
• Consecutive optic atrophy – due to destruction of ganglion cells in retina as in retinitis
pigmentosa, choroiditis.

OPTIC ATROPHY
Central Field Loss

• Traumatic optic atrophy: Avulsion of optic nerve. fracture of skull,
hemorrhage into optic nerve sheath.
• Toxic optic atrophy : exogenous toxins, tobacco alcohol ,
• Metabolic diabetes mellitus
• Demyelination disease – disseminated sclerosis ,
• Hereditary – Leber's disease.

Pathology:
1. Columnar optic atrophy: occurs when degeneration and regeneration are orderly
and the proliferating astrocytes arrange themselves in longitudinal columns
replacing the nerve fiber layers.
2. No pattern optic atrophy occurs when there is replacement of the nerve fibers
with glial tissue which is excessive and is densely tangled.
3. Cavernous optic atrophy occurs when there is degeneration of nerve fibers
without much replacement by glial tissue .

Primary or simple optic atrophy Secondary or post neuritic optic atrophy
Seen in case of syphilis, pituitary tumor
DISC
a) color: white with a bluish tint
b) edges: sharply defined and regular
c) lamina cribrosa seen (stippling)
d) slight atrophic cupping seen
RETINA
a) vessels normal arteries may
be slightly attenuated .
b)surrounding retina is normal in appearance.
• Seen following Papilledema, Papillitis.
• There is proliferation of fibrous tissue on the disc
and along the retinal vessels.
• Dense white, chalky white or grayish white
• Blurred and irregular
• Not seen
• No cupping seen (physiological cup obscured
• Arteries are thin, veins are dilated , both show
sheathing with fibrous tissue
• Surrounding retina shows pigmentary
disturbances which are most common at
macula.

3) Consecutive optic nerve atrophy: seen in retinitis pigmentosa,
choroiditis.
Disc: Yellow, waxy appearance, edge are well defined.
Retina: vessels, show marked attenuation, particularly in case of retinitis
pigmentosa. Surrounding retina shows evidence of retinitis pigmentosa,
choroiditis (pigmentary disturbance).
Peripheral Fields: show concentric contraction or irregular or sector shaped
defects.
Treatment:
-Directed at the cause – anti-syphilitic treatment penicillin in high doses , removal of pituitary tumour.
-vasodilators: nicotinic acid.
-Injection Vitamins B1, B12 in high doses.

• Foster Kennedy Syndrome ( Gowers–Paton–Kennedy syndrome,
Kennedy's phenomenon or Kennedy's syndrome):
Ipsilateral Papilloedema with contralateral Optic atrophy due to frontal lobe tumors
(Robert Foster Kennedy, 1911, British neurologist, who spent most of his life in
USA).1
• Pseudo-Foster Kennedy Syndrome: Ipsilateral optic atrophy with papilledema
in the contralateral eye but with the absence of a mass.2
1. "Foster Kennedy syndrome" at Dorland's Medical Dictionary
2.Bansal S, Dabbs T, Long V (2008). "Pseudo-Foster Kennedy Syndrome due to unilateral optic nerve hypoplasia: a case report". J Med Case
Reports 2: 86.

MEDULATED NERVE FIBERS OR OPAQUE NERVE FIBERS
• Medullation of the optic nerve fibers starts centrally i.e. from the brain and at birth
reaches a level immediately behind the lamina cribrosa , normally the process
ceases here .
• Occasionally patches of nerve fibers on the optic disc or in the retina region
medullary sheath after they have passed through the lamina cribrosa .
• These are called medullated nerve fibers or opaque nerve fibers.

CONGENITAL OPTIC NERVE ANOMALIES
1. Without systemic associations
• Tilted optic disc
• Optic disc Drusen
• Optic disc pit
• Myelinated nerve fibres
2. With systemic associations
• Optic disc coloboma
• Morning glory anomaly
• Optic nerve hypoplasia
• Aicardi syndrome
• Megalopapilla
• Peripapillary staphyloma
• Optic disc dysplasia

Tilted disc • Common, bilateral, Frequent myopia and astigmatism
• VA – normal, Small disc, oval or D-shaped, Axis
oblique (most common), horizontal or vertical, Situs
inversus and inferior crescent, Hypopigmented
inferonasal fundus
Supero-temporal field defects not
obeying vertical midline

Optic Disc Drusen
• Uncommon, bilateral and familial
• Associations - RP, angioid streaks and Alagille
syndrome
• VA - usually normal
Buried Drusen
• Pink or yellow colour
• Indistinct ‘lumpy’ margins
• Anomalous branching patterns with premature
branching
• Absent venous engorgement

Optic disc Drusen
Occasional complications
Emergence from disc surface during early ‘teens’
Waxy pearl-like irregularities
Choroidal neovascularization
Nerve fibre bundle defects
Exposed

FA of Optic Disc Drusen
Autofluorescence prior to dye injection
Late hyperfluorescence confined to disc

Imaging of optic disc Drusen
CT
Ultrasonography

Optic disc pit
• Uncommon, usually unilateral
• VA - normal if uncomplicated
• Large disc containing round or oval pit
• Pit is usually temporal, occasionally central

Optic disc pit and macular detachment
• Incidence - 45% of non-central pits
• Initially - schisis-like separation of inner layers
• Later - serous detachment of outer layers
Treatment
• Laser photocoagulation to temporal disc
• Vitrectomy and gas tamponade if unresponsive

Optic disc Coloboma
• Large disc with inferior excavation
• Superior visual field defects
• May be associated with other
colobomas
• Rare, unilateral or bilateral
• Usually sporadic - occasionally dominant
• VA - decreased
Signs
Ocular associations

Occasional Systemic Associations of Optic Disc Coloboma
 CNS malformation - basal encephalocele and cysts
 Chromosomal anomalies - Patau syndrome (trisomy 13) and cat-eye syndrome (trisomy 22)
 ‘CHARGE’ - Coloboma, Heart defects, choanal Atresia, Retarded development,
Genital and Ear anomalies
 Other syndromes - Meckel-Gruber, Goltz, Lenz microphthalmos, Walker-Warburg and
Goldenhar

Morning gloryanomaly
•Large disc with funnel-shaped excavation
• Basal encephalocele which is frequently
associated with mid-facial anomalies
• Glial tissue within base
• Spoke-like emerging vessels
•Surrounding chorioretinal pigmentary
disturbance
• Serous retinal detachment in about 30%
• Very rare, usually unilateral
• VA - decreased

Optic nerve hypoplasia
• Small disc surrounded by halo
(double ring sign)
• Vessel normal calibre
but may be tortuous
• Rare, unilateral or bilateral
•VA - variable according to severity
• Absence of septum pellucidum
and corpus callosum

Aicardi syndrome
Multiple ‘chorioretinal
lacunae’
• Very rare
• X-linked dominant which is lethal in utero for
males
• Infantile spasms
• Developmental delay
• CNS malformations and early demise
• Disc coloboma and pigmentation

Miscellaneous congenital disc anomalies
Peripapillary staphyloma
Horizontal and vertical disc
diameters more than 2mm
Megalopapilla Optic disc
dysplasia
Marked non-specific disc
Relatively normal disc
within with deep
peripapillary excavation
deformity

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