Neuro ophthalmology 2016

NEURO

OPHTHALMOLOGY

UPDATE 2016

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DR DINESH MITTAL DR SONALEE MITTAL

DRISHTI EYE HOSP DF 63 SCHEME 74 C

VIJAYNAGAR INDORE INDIA

Neuro-Ophthalmic Anatomy

• Medical practice in general—and surgical

subspecialties in particular—are exercises in

applied anatomy. Although an adequate

understanding of physiology and, increasingly,

molecular genetics is important in understanding

disease and potential treatments, anatomy is the

foundation.

Skull Base

Skull Base

• The skull base is connected to

the lower facial skeleton by 3

sets of pillars formed by the

maxillary and zygomatic bones

anteriorly and the pterygoid

process of the sphenoid bone

posteriorly. Superiorly, the

vault of the skull is made up of

the parietal bones, which meet

at the sagittal suture; the

frontal bone, which adjoins

them at the coronal suture; as

well as the occipital bone,

which meets the parietal

bones at the lambdoid suture.

Anatomy Of Right Orbital Apex

• The optic foramen transmits the optic nerve,

ophthalmic artery, and oculosympathetic nerves.

• The superior orbital fissure, a gap between the greater

and lesser wings of the sphenoid bones, transmits CNs

III, IV, VI, V1, and the superior ophthalmic vein. Within

the lesser wing of the sphenoid bone is the optic

foramen, which leads to the optic canal. The optic strut

separates the optic canal from the superior orbital

fissure.

• The 4 rectus muscles arise from the annulus of Zinn.

CNs II, III (superior and inferior branches), VI, and the

nasociliary nerve all course through the annulus of

Zinn. CN IV and the frontal and lacrimal nerves and the

ophthalmic veins are located outside the annulus.

The medial orbital wall

• The medial orbital wall is

formed by 4 bones: maxilla

(frontal process), lacrimal,

sphenoid, and ethmoid. The

largest component of the

medial wall is the lamina

papyracea of the ethmoidal

bone. The anterior medial

orbital wall includes the

lacrimal sac fossa, which is

formed by both the maxillary

and lacrimal bones. The

lacrimal bone is divided by the

posterior lacrimal crest. The

anterior part of the lacrimal

sac fossa is formed by the

anterior lacrimal crest of the

maxillary bone.

Basal view of the brain showing the

anterior and posterior visual pathways

THREE

MAJOR

SENSORY

DIVISIONS OF

TRIGEMINAL

NERVE

Pupilloconstrictor light reflex

pathway

Pupillary dilatation pathway

Lesions of the pupil

Horner’s syndrome

PHARMACOLOGY OF THE PUPIL

PHARMACOLOGY OF THE PUPIL

Pharmacological tests to localize

Horner’s syndrome

Dilated pupil

SUPRANUCLEAR AND

INFRANUCLEAR PATHWAYS

• Anatomical pathways, which extend from the cortical

centers of brain to the cranial nerve nuclei, are called the

supranuclear pathways. From the cranial nerve nuclei to

the ocular muscle exist the infranuclear pathways . In

peripheral nerves, the nerve starts from the brain and

reaches the anterior horn cell in the spinal cord. This is the

upper motor neuron. From the anterior horn cell of the

spinal cord, the nerve moves to the peripheral muscle. This

is the lower motor neuron. If there is a lower motor neuron

disease the limb is flaccid and if there is an upper motor

neuron disease the limb is spastic.

UMN VS LMN VS MYOPATHY

SUPRANUCLEAR AND

INFRANUCLEAR PATHWAYS

• The cranial nerve nuclei are like peripheral nerve

nuclei. From cortex of the brain the nerve extends to

the cranial nerve nuclei and this is the upper motor

neuron (UMN) pathway. From the cranial nerve nuclei

the nerve extends to the ocular muscle and this is the

lower motor neuron (LMN) pathway. In peripheral

nerves if the anterior horn cell gets involved as in

poliomyelitis, the patient has a LMN disease and so the

limb is flaccid. The anterior horn cell is akin to the

cranial nerve nuclei of cranial nerves. So, if the cranial

nerve nuclei gets involved the lesion produced will be a

LMN lesion.

The corticospinal and bulbospinal upper

motor neuron pathways.

Ocular Motor Cranial

Nerves

Ocular Motor Cranial Nerves

• Without neural activity, the visual axes are usually

mildly to moderately divergent. The major tonic

input to ocular motility is supplied by 3 pairs of

ocular motor cranial nerves—CNs III, IV, & VI—that

innervate the 6 EOMs controlling ocular movement

. In addition, CN III innervates the levator

palpebrae superioris and the pupillary sphincter

muscles.

Ocular Motor Cranial Nerves

• Except for the inferior oblique muscle, the

innervation to each of the EOMs occurs

approximately one-third the distance from the

apex. The inferior oblique muscle receives its

innervation at approximately its midpoint from a

neurovascular bundle running parallel to the lateral

aspect of the inferior rectus muscle. All 6 EOMs

receive their innervation on the inside surface,

except for the superior oblique, where branches of

CN IV terminate on the upper (outer) surface of the

muscle.

Medical management of stroke

and TIA.

Neuro ophthalmology exam


• In ophthalmology, diagnoses are often made by visual clues.

While in neuro-ophthalmology, a thorough history is the

foundation of accurate diagnosis. While conversing with the

patient, note the following: gait, facial features, eyes, ocular

adnexa, hands, clothing, and mannerisms. After a detailed history

and physical examination the diagnosis is usually apparent.

• It is said that a neuro-ophthalmologist is a ‘thinking’ or ‘cognitive’

ophthalmologist. His aim is twofold:

• Localise lesion (Where)—Retina, optic nerve, optic chiasm, optic

tract, lateral geniculate body, optic radiation, occipital cortex

• Suspect the pathology (What)—VIN DITCH MD (Vascular,

Infectious, Neoplastic, Demyelinating, Inflammatory, Traumatic,

Congenital, Heredofamilial, Metabolic, Drug induced)


• When you come across a suspected neuro-

ophthalmic patient, set aside atleast 15-20 minutes

of the clinic time for a detailed history and

examination.

• Record the patient’s age, gender and occupation.

• Optic neuritis is generally seen in women between

20 and 40 years of age. Ischemic optic neuropathy

is mostly seen after the age of 40 years. Traumatic

optic neuropathy is more common in young males

riding two wheelers.


• Thyroid eye disease, myasthenia gravis, benign

intracranial hypertension, meningiomas and

multiple sclerosis are more common in females.

Craniopharyngioma, optic nerve glioma and

rhabdomyosarcoma are most commonly seen in the

pediatric population. Traumatic optic neuropathy,

intracranial and orbital foreign bodies, subdural

hematoma, intracerebral hemorrhage and

ophthalmoplegia are more common in the armed

forces and police due to the high incidence of

trauma.

CHIEF COMPLAINT

•It helps to ask the

patient—‘Tell me in one

sentence what your

problem is. Record the

chief complaint in the

patient’s own words.

Decreased Vision

• Transient visual loss (vision returns to normal within

24 hours, usually within one hour):

• Few seconds: Papilledema

• Few minutes: Amaurosis fugax, vertebrobasilar

insufficiency

• 10-60 minutes: Migraine (with or without subsequent

headache), Impending crvo , ischemic optic neuropathy,

carotid occlusive disease, CNS lesion, optic disc drusen,

giant cell arteritis.

Decreased Vision

• Visual loss lasting more than 24 hours

a. Sudden painless: Retinal artery or vein occlusion,

ischemic optic neuropathy, vitreous hemorrhage,

retinal detachment

b. Gradual painless loss: open angle glaucoma,

diabetic retinopathy, and compressive optic

neuropathy

c. Painful loss: acute angle closure glaucoma, optic

neuritis, uveitis

Color Vision

• Loss of Color Vision

• Optic neuritis, other optic neuropathies.

• Loss of Side Vision

• Right or left hemifield—stroke, pituitary tumor,

glioma,

• subdural hematoma, migraine

• Upper or lower hemifield—AION, optic neuritis

• Central—optic neuritis, toxic neuropathy


• Loss of Contrast of Vision

• Optic neuritis.

• Shaking of Objects (oscillopsia) or Eyes

• Acquired nystagmus (vertical or horizontal).

• Eye Pain (Orbital)

• Sinusitis, orbital pseudotumor, optic neuritis, diabetic

nerve palsy

Headache

•Malignant hypertension, increased

intracranial pressure, infectious CNS

disorder, giant cell arteritis, cerebral

tumor, aneurysm, subarachnoid

hemorrhage, epidural or subdural

hematoma, migraine, cluster headache,

tension, trigeminal neuralgia, Tolosa

Hunt disease, cervical spine disease.

Double Vision

• Binocular (Double vision is eliminated when either eye

is occluded).

• a. Typically intermittent: myasthenia gravis,

intermittent decompensation of existing phoria

b. Constant: Isolated sixth, third or fourth nerve palsy,

thyroid eye disease, inflammatory pseudotumor,

cavernous sinus superior orbital fissure syndrome,

post-trauma-blowout fracture, internuclear

ophthalmoplegia, vertebrobasilar insufficiency.

Eyelid

Drooping of Eyelid (Ptosis)

• Aging, myasthenia gravis, Horner’s syndrome, third

• nerve palsy, chronic progressive external ophthalmoplegia.

Lid Retraction

• Thyroid eye disease, midbrain syndrome.

Prominence of Eye (Proptosis)

• Thyroid eye disease, orbital cellulitis, pseudotumor,

• orbital tumors, trauma, varix, mucormycosis.

TENSILON TEST

Tensilon/Enlon (edophonium

hydrochloride) is available in India in

a multidose 10 mg/ml bottle

EVALUATION

•It is essential to evaluate

all cranial nerve functions

in a patient with

ophthalmoplegia or

seventh nerve palsy .

Oculomotor nerve (CN III)

Oculomotor nucleus complex.

• all extraocular muscles

served by CN III are

innervated by their

respective ipsilateral

nuclei except the

superior rectus muscle.

Parasympathetic fibers

traveling to the

pupillary sphincter

muscle synapse in the

ciliary ganglion in the

orbit .


• The nucleus of the oculomotor nerve (CN III) is located

dorsally within midbrain beneath aqueduct connecting

the third and fourth ventricles . The nuclear complex

itself represents a collection of subnuclei that have

specific identifiable functions . The fibers destined to

innervate the levator palpebrae superioris, medial

rectus, inferior rectus, pupil sphincter, and ciliary body

muscles exit ventrally ipsilateral to the individual

nuclei from which they originate. In contrast, the fibers

from the superior rectus subnucleus, which lies along

the midline, cross before exiting the brainstem to

innervate the superior rectus muscle.


• Unilateral supratentorial mass lesions may force the

uncus through the tentorial notch (uncal herniation) to

compress the ipsilateral CN III. Running forward in the

superior lateral wall of the cavernous sinus, the nerve

separates into a superior and an inferior division. These

divisions enter the orbit through the superior orbital

fissure within the annulus of Zinn. The superior division

runs forward intraconally to innervate first the superior

rectus muscle and then the levator palpebrae

superioris muscle. The inferior division sends

parasympathetic fibers to the ciliary ganglion in the

orbital apex approximately 10 mm anterior to the

annulus of Zinn and lateral to the optic nerve.

Lateral view of the course of CNs

III, IV, and VI.


• Within the ciliary ganglion, the fibers destined for

the pupillary sphincter and the ciliary body

synapse. The fibers subsequently accompany the

branch destined for the inferior oblique muscle.

There are 9–10 times as many fibers associated

with accommodation innervating the ciliary body

as there are fibers reaching the pupillary sphincter

muscle. This disparity may be one reason for the

development of light–near dissociation in Adie tonic

pupil . The remaining branches of CN III within the

orbit innervate the medial rectus and inferior

rectus muscles.

Oculomotor, Trochlear and Abducens Nerves

(3rd, 4th and 6th Cranial Nerves)

•In a third nerve palsy, the fourth

nerve can be assessed by looking at

a superior conjunctival vessel with

the naked eye or on the slit lamp

and asking the patient to look down

and nasally. The eye should intort

and the vessel should move down

and towards the nose .

COMPRESSIVE LESION INVOLVES PUPIL

•a compressive lesion of the third nerve

(particularly an aneurysm) will cause a

fixed, dilated pupil. In contrast, third

cranial nerve palsy from an ischemic

mononeuropathy (diabetes mellitus,

hypertension) demonstrates no

anisocoria and the pupil is briskly

reactive .

MANAGEMENT

• Consider checking blood pressure and ordering

laboratory studies (eg, CBC, fasting blood sugar,

hemoglobin A1C, ESR, and CRP) in patients with a

pupil-sparing third nerve palsy. ASPIRIN

PRESCRIBED ( USUALLY 75 MG TO 150 MG )

• The patient should be instructed to call if the

initially uninvolved pupil dilates or if there are new

signs or symptoms suggestive of an aneurysm.

• Atypical features for ischemic palsy should prompt

consideration for obtaining an MRI with MRA or CTA

Oculomotor, Trochlear and Abducens Nerves

(3rd, 4th and 6th Cranial Nerves)

• Immediate MRI to rule out mass/aneurysm is indicated for:

1. Pupil involving third nerve palsies

2. Pupil sparing third nerve palsies in:

a. Patients without diabetes or hypertension

b. Patients with incomplete third nerve palsies

c. Third nerve palsies over 3 months in duration,not

improving

d. Associated additional cranial nerve or neurologic

abnormalities.

3. All non-traumatic aberrant regeneration of third

nerve palsies.

Aberrant regeneration

• Aberrant regeneration may occur spontaneously

without preceding third nerve palsy in cavernous

sinus tumor or aneurysm. Signs of aberrant

regeneration in 3rd nerve palsy are:

• Pseudo Von Graefe’s sign Lid elevation on down

gaze

• Inverse Duane’s sign Lid elevation on adduction

• Pseudo Argyll Robertson pupil Pupillary

constriction on adduction, no reaction to light .

Fourth nerve

Fourth nerve

• The fourth (trochlear) cranial nerve supplies only

the superior oblique muscle.

• It is a very long and slender nerve, increasing its

vulnerability.

• It is the only cranial nerve to emerge from the

dorsal aspect of the brain. It is the only crossed

cranial nerve besides the optic nerve, innervating

the superior oblique muscle contralateral to its

nucleus.

• It has the fewest axons of any of the cranial

nerves.

Causes of isolated fourth nerve palsy

• Idiopathic lesions are common, and many of these

are thought to be congenital although symptoms

may not develop until decompensation occurs in

adult life due to reduced fusional ability. In contrast

to acquired lesions patients are not usually aware

of the torsional aspect, but may develop vertical

double vision that is often appreciated as of

sudden or subacute onset

Causes of isolated fourth nerve palsy

• Trauma frequently causes bilateral fourth nerve

palsy. The long and slender nerves are particularly

vulnerable as they decussate in the anterior

medullary velum, through impact with the tentorial

edge. Care must be taken not to mistake a bilateral

palsy for a unilateral lesion, particularly when

corrective surgery is contemplated.

• Microvascular lesions are relatively common, this

aetiology often being presumed when appropriate

systemic risk factors are present in the absence of

features of congenital onset.

Sixth nerve

Sixth nerve

• The nucleus of the sixth (abducens or abducent) nerve

lies at the mid-level of the pons, ventral to the floor of

the fourth ventricle. The fibres (fasciculus) leave the

brainstem ventrally at the pontomedullary junction.

• Nuclear lesion. A nuclear sixth nerve lesion also

causes a failure of horizontal gaze towards the side of

the damage due to involvement of the adjacent

horizontal gaze centre (paramedian pontine reticular

formation). Facial (seventh) nerve fibres wrap around

the sixth nerve nucleus, so ipsilateral lower motor

neurone (LMN) facial nerve palsy is also common.

Isolated sixth nerve palsy is never nuclear in origin.

Sixth nerve

• Foville (inferior medial pontine) syndrome is most

frequently caused by vascular disease or tumours

involving the dorsal pons. It is characterized by

ipsilateral involvement of the fifth to eighth cranial

nerves, central sympathetic fibres (Horner syndrome)

and horizontal gaze palsy.

• • Millard–Gubler (ventral pontine) syndrome involves

the fasciculus as it passes through the pyramidal tract

and is most frequently caused by vascular disease,

tumours or demyelination. As well as ipsilateral sixth

nerve palsy, there is contralateral hemiplegia and often

an ipsilateral LMN facial nerve palsy.

Treatment

• Observation with monocular occlusion or prismatic

(e.g. temporary Fresnel stick-on) correction of diplopia

is appropriate in idiopathic and presumed

microvascular lesions; up to 90% will recover

spontaneously, usually over weeks to several months.

Young children should be treated with alternate

patching to prevent amblyopia.

• Botulinum toxin injection into the ipsilateral medial

rectus may be used to prevent contracture, assess

residual function and sometimes to facilitate prismatic

correction with a large deviation ; it is rarely curative.

• Surgery should be considered only when adequate

time has been allowed for maximal spontaneous

recovery .

Summary

• Brain MRI (with or without orbital views) is

indicated in all patients with acute sixth nerve

palsies who have no known vascular risk factors.

• Management of a transient (eg, ischemic) sixth

nerve palsy may include temporary patching of the

eye or fogging of a spectacle lens with semiopaque

tape.

• Strabismus surgery may be the best option for

patients with chronic deviations who fail or are

• intolerant of conservative measures

Sensory and Facial

Motor Anatomy

Trigeminal Nerve (CN V)

Trigeminal Nerve (CN V)

• Although importance of CNs II, III, IV, and VI is

obvious, CN V and CN VII also have important

impacts on normal ophthalmic function and are

frequently involved in neuro-ophthalmic disorders.

For example, proper functioning of CN V is

essential for preventing corneal damage. In

addition, complete loss of corneal sensation may

be accompanied by abnormal corneal epithelial

growth (neurotrophic keratitis associated with loss

of neural secreted growth factors).

Lateral view of the orbit, showing

its sensory nerves

The 3 divisions of CN V synapse in

the trigeminal (gasserian) ganglion

• The ophthalmic division (V1) is the most anterior

branch exiting the trigeminal ganglion. It runs forward

within the lateral wall of the cavernous sinus just

below CN IV. As it approaches the superior orbital

fissure extradurally, it divides into 3 major branches:

lacrimal, frontal, and nasociliary. In addition, small

branches innervate the dura of the anterior middle

cranial fossa, including the cavernous sinus, the

parasellar region, the tentorium, and the dura of the

petrous apex.

• These branches also innervate the floor of the anterior

cranial fossa, including the falx and the major blood

vessels at the skull base.

divisions of CN V

• The lacrimal and frontal nerves enter orbital apex

outside annulus of Zinn. At its terminus, the frontal

nerve divides into supraorbital and supratrochlear

branches, which innervate the forehead, frontal

sinus, and upper eyelid (including the conjunctiva).

The lacrimal nerve also runs anteriorly in superior

lateral orbit just above the lateral rectus to

innervate lacrimal gland and some skin just

superotemporal to the orbit. The nasociliary branch

is the only branch entering the intraconal space

through the annulus of Zinn.

divisions of CN V

• The nasociliary branch runs through the ciliary

ganglion and anteriorly to innervate the globe

through the short and long posterior ciliary nerves.

Prior to reaching globe, branches from the

nasociliary division pass through the anterior and

posterior ethmoidal foramina to innervate part of

the ethmoidal sinuses, the lateral wall of the nose,

and the skin of the nose to the nasal tip. This co-

innervation of the globe and the nasal skin is the

reason behind the development of the Hutchinson

sign in patients with zoster ophthalmicus.

divisions of CN V

• The maxillary division (V2) runs forward at the inferior

lateral base of the cavernous sinus to enter the

foramen rotundum, located just below the superior

orbital fissure. Just before entering the canal, V2 gives

off the middle meningeal nerve, which supplies the

dura of the lateral middle cranial fossa. On the anterior

end of the foramen rotundum, V2 enters the

pterygomaxillary area. Two large pterygopalatine

nerves supply sensation to the nasopharynx, hard and

soft palate, and portions of the nasal cavity. Posterior

alveolar nerves supply sensation to the upper gums and

molars.

divisions of CN V

• The zygomatic nerve enters the orbit through the

inferior orbital fissure and divides into

zygomaticofacial and the zygomaticotemporal

nerves, which supply sensation to lateral face . The

maxillary nerve continues anteriorly within a canal

between the orbit above and the maxillary sinus

below to exit through the infraorbital foramen (as

the infraorbital nerve) just below the inferior orbital

rim. It subsequently divides into palpebral, nasal,

and labial branches. The sensation of the cheek as

well as the lower eyelid and upper teeth and gums

is provided by this division.

divisions of CN V

• mandibular division (V3) enters through foramen

ovale, lateral to foramen lacerum and medial to

the foramen spinosum (carrying the MMA). V3

innervates the skin of the jaw and carries the

motor division of the trigeminal nerve to the

muscles of mastication and neck. Motor paralysis

results in contralateral deviation of the jaw when it

is closed (weakness of the temporalis) and

ipsilateral deviation when protruded (because of

weakness in the lateral pterygoid).

Facial Nerve (CN VII)


• Figure 1-38 Supranuclear, nuclear, and infranuclear anatomy

of the facial nerve (CN VII).

• A, The corticobulbar fibers travel through the internal

capsule down into the medial one-third of the corticospinal

tracts in the cerebral peduncles of the midbrain. The

pathways for the upper third of facial function (brow and

orbicularis muscles) run parallel but apparently distinct

from pathways for the lower two-thirds along the pyramidal

tracts. The corticobulbar fibers travel in the basis pontis;

those that control the lower facial muscles decussate at the

level of the pons to synapse on the contralateral CN VII

nucleus. Corticobulbar fibers that control the upper facial

muscles decussate to synapse on the contralateral CN VII

nucleus, and some of the fibers do not cross, reaching the

ipsilateral CN VII nucleus


• B, CN VII is predominantly motor in function, with its

nucleus located in the caudal pons. CN VII courses

dorsomedially and encircles the nucleus of CN VI. After

bending around the CN VI nucleus, CN VII exits the pons in

the cerebellopontine angle close to CN V, CN VI, and CN

VIII. CN VIII, the motor root of CN VII, and the nervus

intermedius (the sensory and parasympathetic root of CN

VII) enter the internal auditory meatus. Sensory cells

located in the geniculate ganglion continue distally as the

chorda tympani nerve, which carries taste fibers. Peripheral

fibers of the nervus intermedius portion of CN VII initiate

salivary, lacrimal, and mucous secretion.

• C, After emerging from the parotid gland, CN VII innervates

the muscles of facial expression via 5 peripheral branches.

The facial nerve. A, B, and C denote lesions of the facial nerve at the stylomastoid

foramen, distal and proximal to the geniculate ganglion, respectively. Green lines

indicate the parasympathetic fibers, red line indicates motor fibers, and purple

lines indicate visceral afferent fibers (taste)


• Within the petrous bone, CN VII enters the fallopian

canal and traverses 3 segments (the labyrinthine, the

tympanic, and the mastoid) that run in close proximity

to the semicircular canals. The parasympathetic fibers

destined for the lacrimal gland separate from CN VII in

the region of the geniculate ganglion to accompany the

greater superficial petrosal nerve. The stapedial nerve

exits to innervate the stapedius muscle, and chorda

tympani conducts parasympathetic innervation to the

submaxillary gland and afferent fibers from the anterior

two-thirds of the tongue. These special afferent fibers

are responsible for taste in the anterior tongue and

synapse in the geniculate ganglion.


• The main branch of CN VII exits the stylomastoid

foramen just behind the styloid process at the base of

the mastoid. The extracranial trunk of the nerve

passes between the superficial and deep lobes of the

parotid gland, where it divides into 2 trunks: the

temporofacial superiorly and the smaller cervicofacial

inferiorly. These further variably divide into 5 major

branches: the temporal, zygomatic, infraorbital, buccal,

and mandibular. The temporal and zygomatic branches

laterally innervate the orbicularis oculi muscles. The

infraorbital and buccal branches may also contribute to

the inferior orbicularis.

Facial Nerve (7th Cranial Nerve)—Test for

• Raising the eyebrows.

• Ask the patient to gently close the eyelids as if they

are sleeping. The amount of lagophthalmos can be

measured with a millimeter rule .

• Forceful closure of eyes for orbicularis oculi,

• Blink reflex—Loss of spontaneous blink may occur

in patients with apparently normal voluntary lid

closure, and is a helpful clue to suggest prior seventh

nerve palsy.

Facial Nerve (7th Cranial

Nerve)—Test for

• Blowing the mouth, saying “eee”—look for deviation

of the mouth.

• Taste sensation of the anterior two-thirds of the

tongue.

• Tear function—Schirmer’s test.

• Bell’s phenomenon—it indicates how well the

cornea is protected when the patient is asleep.

Facial Nerve PALSY

• A complete interruption of the facial nerve at the

stylomastoid foramen paralyzes all muscles of facial

expression. The corner of the mouth droops, the

creases and skinfolds are effaced, the forehead is

unfurrowed, and the eyelids will not close. Upon

attempted closure of the lids, the eye on the paralyzed

side rolls upward (Bell's phenomenon). The lower lid

sags and falls away from the conjunctiva, permitting

tears to spill over the cheek. Food collects between the

teeth and lips, and saliva may dribble from the corner

of the mouth. The patient complains of a heaviness or

numbness in the face, but sensory loss is rarely

demonstrable and taste is intact.

Facial Nerve PALSY

• If the lesion is in the middle-ear portion, taste is

lost over the anterior two-thirds of the tongue on

the same side. If the nerve to the stapedius is

interrupted, there is hyperacusis (sensitivity to

loud sounds). Lesions in the internal auditory

meatus may affect the adjacent auditory and

vestibular nerves, causing deafness, tinnitus, or

dizziness. Intrapontine lesions that paralyze the

face usually affect the abducens nucleus as well,

and often the corticospinal and sensory tracts.


• If the peripheral facial paralysis has existed for

some time and recovery of motor function is

incomplete, a continuous diffuse contraction of

facial muscles may appear. The palpebral fissure

becomes narrowed, and the nasolabial fold

deepens. Attempts to move one group of facial

muscles may result in contraction of all

(associated movements, or synkinesis). Facial

spasms, initiated by movements of the face, may

develop (hemifacial spasm).


• Anomalous regeneration of seventh nerve fibers

may result in other troublesome phenomena. If

fibers originally connected with the orbicularis

oculi come to innervate the orbicularis oris, closure

of the lids may cause a retraction of the mouth, or

if fibers originally connected with muscles of the

face later innervate the lacrimal gland, anomalous

tearing ("crocodile tears") may occur with any

activity of the facial muscles, such as eating.

Another facial synkinesia is triggered by jaw

opening, causing closure of the eyelids on the side

of the facial palsy (jaw-winking).

BELL’S PALSY

• The most common form of facial paralysis is Bell’s palsy.

The annual incidence of this idiopathic disorder is ~25 per

100,000 annually, or about 1 in 60 persons in a lifetime. Risk

factors include pregnancy and diabetes mellitus.

• Clinical Manifestations The onset of Bell’s palsy is fairly

abrupt, with maximal weakness being attained by 48 h as a

general rule. Pain behind the ear may precede the paralysis

for a day or two. Taste sensation may be lost unilaterally,

and hyperacusis may be present.

• In some cases, there is mild cerebrospinal fluid

lymphocytosis. Magnetic resonance imaging (MRI) may

reveal swelling and uniform enhancement of the geniculate

ganglion and facial nerve and, in some cases, entrapment of

the swollen nerve in the temporal bone.

BELL’S PALSY

• Approximately 80% of patients recover within a few

weeks or months. Electromyography may be of

some prognostic value; evidence of denervation

after 10 days indicates there has been axonal

degeneration, that there will be a long delay (3

months as a rule) before regeneration occurs, and

that it may be incomplete. The presence of

incomplete paralysis in the first week is the most

favorable prognostic sign. Recurrences are

reported in approximately 7% of cases.

TREATMENT Bell’s Palsy

•Symptomatic measures include (1) the use of

paper tape to depress the upper eyelid

during sleep and prevent corneal drying, and

(2) massage of the weakened muscles.

•A course of glucocorticoids, given as

prednisone 60–80 mg daily during the first 5

days and then tapered over the next 5 days,

modestly shortens the recovery period and

improves the functional outcome.

TREATMENT Bell’s Palsy

• Although large and wellcontrolled randomized trials

found no added benefit of the antiviral agents

valacyclovir (1000 mg daily for 5–7 days) or

acyclovir (400 mg five times daily for 10 days)

compared to glucocorticoids alone, some earlier

data suggested that combination therapy with

prednisone plus valacyclovir might be marginally

better than prednisolone alone, especially in

patients with severe clinical presentations.

Ocular Autonomic Pathways

• Branches of parasympathetic system play a role in

lacrimal function, and pupil size is controlled by a

balance between innervation of sympathetic fibers

to iris dilator muscles and of parasympathetic

fibers to the sphincter muscles. The accessory

retractor muscles, including the Müller muscle in

the upper eyelid, receive sympathetic innervation.

Sympathetic Pathways

• Sympathetic activity originates in the posterolateral

region of the hypothalamus. Activity in the

hypothalamus is influenced by signals in the frontal,

sensorimotor, and occipital cortex and in the limbic

system (cingulate gyrus). The course of sympathetic

fibers destined for the orbit is divided into first-,

second-, and third-order segments . Axons destined for

the dilator muscles of the pupil and Müller muscle

descend as the first-order segment, along with other

sympathetic fibers, superficially in the anteromedial

column through the brainstem to the spinal cord. the

sympathetic fibers destined for the orbit synapse in the

ciliospinal center of Budge-Waller .


• The postsynaptic second-order fibers leave the spinal cord

through the ventral rami of the cervical (C8) and upper

thoracic (T1 and T2) levels before joining the paravertebral

sympathetic plexus. Ascending rostrally, the sympathetic

chain passes in the anterior loop of the ansa subclavia

proximate to the innominate artery on the right and the

subclavian artery on the left just above the lung apex.

These fibers pass through the inferior and middle cervical

ganglia to terminate in the superior cervical ganglion, at the

level of the angle of the jaw (C2) and the carotid artery

bifurcation.

• The postganglionic third-order fibers continue in the wall of

the bifurcated carotid. Sympathetic fibers innervating the

sweat glands of the lower face follow the ECA.

Anatomy of

the

sympathetic

pathway


• anteriorly in the cavernous sinus, the sympathetic fibers

join the nasociliary branch of V1. In the orbital apex, the

fibers then pass through the ciliary ganglion (without

synapsing). Along with the nasociliary branch, the

sympathetic fibers reach the globe and travel with the long

ciliary nerves to the dilator muscles of the pupil. The dilator

muscle lies just superficial to the posterior pigment

epithelium of the iris, which continues peripherally as the

nonpigmented superficial layer of the ciliary body. The

myoepithelial cells measure approximately 12.5 μm in

thickness, with an apical epithelial portion and a basilar

muscular portion that is oriented radially toward the

pupillary opening. The muscular processes terminate

peripheral to the sphincter muscle. Peripherally at the iris

root, these cells are continuous with the pigmented

epithelium of the ciliary body.


• The fibers destined for the Müller muscle travel

along the OphA and its subsequent frontal &

lacrimal branches. The Müller muscle originates

near the origin of the levator aponeurosis and

inserts 10–12 mm inferiorly on the superior border

of the tarsus. The superior orbital sympathetic

fibers also innervate the sweat glands of the

forehead. Thus, disruption of these sympathetic

fibers is responsible for the mild ptosis and the

frontal anhidrosis associated with distal Horner

syndrome.

Parasympathetic Pathways

• Parasympathetic activity originates in various areas within

brainstem. The fibers that control pupil sphincter muscles

originate in the Edinger-Westphal (EW) nuclei of CN III

nuclear complex within the midbrain. The main input to the

EW nuclei is from the pretectal nuclei, both directly and via

the posterior commissure. The pretectal nuclei, in turn,

receive input directly from the afferent visual pathways via

the pupillary tract, which leaves the optic tract in the

brachium of the superior colliculus just anterior to the LGN.

The cortex (especially the frontal lobes), the hypothalamus,

and the reticular activating system provide tonic inhibitory

signals to the EW nucleus.

• During sleep, the pupil becomes smaller through loss of this

inhibitory activity.

Pathway of the pupillary reaction

to light

Parasympathetic Pathways

• The parasympathetic fibers and the CN III fascicles

leave the CN III nucleus and exit in the interpeduncular

fossa. Within the subarachnoid space, the

parasympathetic fibers tend to run on the medial

superficial surface of CN III. When CN III bifurcates in

the anterior cavernous sinus, the parasympathetic

fibers travel with the inferior division. In the orbital

apex, these fibers synapse in the ciliary ganglion (as

opposed to the oculosympathetic and nasociliary

fibers, which travel through the ganglion without

synapse). The postsynaptic fibers then travel with the

branch destined for the inferior oblique muscle to join

the posterior ciliary nerves to reach anterior segment

and iris sphincter muscles.

Parasympathetic innervation to the lacrimal gland

• Parasympathetic innervation to the lacrimal gland

originates in the superior salivatory (salivary) nucleus

located in the caudal pons posterolateral to the motor

nucleus of CN VII. This nucleus receives sensory input from

the trigeminal nerve and additional afferent fibers from the

hypothalamus. Efferent parasympathetic fibers for lacrimal,

mucous, and salivary secretion leaving the nucleus join

other parasympathetic efferent fibers coming from the

salivatory nucleus and run with afferent gustatory fibers

from the anterior two-thirds of the tongue in the nervus

intermedius. The gustatory fibers synapse in the nucleus of

the tractus solitarius parallel to the fascicles of CN VII in

the nervus intermedius . This nerve joins with CN VII to exit

the brainstem on its ventral surface of the pontomedullary

junction.

SUPRANUCLEAR EYE

MOVEMENT SYSTEMS

• There are five supranuclear eye movement

systems. They are:

• 1. Saccadic system

• 2. Pursuit system

• 3. Vergence system

• 4. Non-optic reflex system

• 5. Position maintenance system.

HORNER SYNDROME

• A 55-year-old man with hypertension complains of

acute headache on the left and is found to have a

left Horner syndrome. How should he be worked up

and treated?

• This patient with an acute, isolated, painful Horner

syndrome is considered to have a left internal

carotid artery dissection until proven otherwise. He

must be evaluated emergently with noninvasive

cerebrovascular imaging studies. If a dissection is

confirmed, he will have to be admitted and treated

to prevent a cerebral infarction .

Treatment of Horner Syndrome

• Most patients with Horner syndrome have no visual

changes and tolerate a mild ptosis. Rarely, lid

surgery is requested to correct a persistent ptosis.

Topical apraclonidine corrects the ptosis

associated with Horner syndrome and may be used

intermittently for cosmetic reasons or when the

ptosis reduces the superior visual field.

Papilloedema

Papilloedema

• Papilloedema is swelling of the optic nerve head

secondary to raised intracranial pressure (ICP).

‘Disc swelling’ and ‘disc oedema’ are non-specific

terms that include papilloedema but also a disc

swollen from other causes. All patients with

papilloedema should be suspected of harbouring an

intracranial mass. Not all patients with raised ICP

will develop disc swelling.

Cerebrospinal fluid Circulation

• Cerebrospinal fluid (CSF) is formed by the choroid

plexus in the ventricles of the brain.

• It leaves the lateral ventricles to enter the third

ventricle through the foramina of Munro.

• From the third ventricle, it flows through the

Sylvian aqueduct to the fourth ventricle.

• From the fourth ventricle, the CSF passes through

the foramina of Luschka and Magendie to enter the

subarachnoid space, flowing around the spinal cord

and bathing the cerebral hemispheres.

Cerebrospinal fluid Circulation

• Absorption is into the cerebral venous system through arachnoid villi.

• Normal CSF pressure on lumbar puncture is 10–18 cmH2O in adults.

• • Causes of raised ICP

• Idiopathic intracranial hypertension.

• Obstruction of the ventricular system by congenital or acquired lesions.

• Space-occupying intracranial lesions, including haemorrhage.

• Impairment of CSF absorption due to meningitis, subarachnoid

haemorrhage or trauma.

• Cerebral venous sinus thrombosis.

• Cerebral oedema from blunt head trauma.

• Severe systemic hypertension.

Diagnosis of raised ICP

• Headaches, which characteristically occur early in the

morning and may wake the patient from sleep, although

less commonly they can occur at any time of day. The

pain may be generalized or localized, and may intensify

with head movement, bending or coughing. They tend

to get progressively worse over time. Very rarely,

headache may be absent.

• Nausea, often episodic and with associated projectile

vomiting; may occur as an isolated feature or may

precede the onset of headaches.

• Deterioration of consciousness as severity increases,

initially with drowsiness and somnolence. A dramatic

deterioration in concscious level may be indicative of

brainstem distortion and requires immediate attention.


• Visual symptoms are commonly absent in mild or early

raised ICP.

• Transient visual obscurations lasting up to 30 seconds in

one or both eyes are frequent in established papilloedema,

and are sometimes precipitated by bending, coughing or the

Valsalva manoeuvre; disc swelling due to other causes is

usually associated with more persistent visual impairment.

• Horizontal diplopia due to sixth nerve palsy caused by

stretching of one or both abducens nerves over the petrous

tip ; this is a false localizing sign.

• Vision is generally normal or minimally reduced. Significant

reduction is a late feature in conjunction with secondary

optic atrophy.


• MRI to exclude a space-occupying lesion and/or

enlarged ventricles; MRI can also be used to

measure ONSD (average normal diameter

approximately 5.5 mm ± 1 mm on MRI).

• In certain cases vascular imaging may be

performed, such as venography to rule out cerebral

venous sinus thrombosis.

• Lumbar puncture (LP) must not be carried out until

imaging has excluded a space-occupying lesion

that might cause downwards herniation of the

intracranial

OPHTHALMOSCOPIC PICTURE

• It is useful to characterize the changes in the optic nerve head that occur in

papilledema as being mechanical or vascular in nature.

• The five mechanical clinical signs of optic disc

edema are:

• Blurring of the optic disc margins.

• Filling in of the optic disc cup.

• Anterior extension of the nerve head (3 D = 1 mm

of elevation).

• Edema of the nerve fiber layer.

• Retinal or choroidal folds, or both.

The five vascular clinical signs of

optic disc edema

• Venous congestion of arcuate and peripapillary

vessels.

• Papillary and retinal peripapillary hemorrhages.

• Nerve fiber layer infarcts (cotton-wool spots).

• Hyperemia of the optic nerve head.

• Hard exudates of the optic disc.

Stages of papilloedema

• Papilloedema is nearly always bilateral, but may be

asymmetrical.

• • Early Mild disc hyperaemia with preservation of the

optic cup.

• Indistinct peripapillary retinal nerve striations and disc

margins.

• SVP is absent in about 20% of normal individuals and

may be difficult to identify even when present. An

identifiable venous pulsation in at least one eye means

that the ICP is normal at that point in time, bearing in

mind that diurnal fluctuation can occur.


• Established (acute –)

• Normal or reduced VA.

• Severe disc hyperaemia, moderate elevation with indistinct margins and

absence of the physiological cup.

• Venous engorgement, peripapillary flame haemorrhages and frequently

cotton wool spots.

• As the swelling increases, the optic nerve head appears enlarged.

• Circumferential retinal folds (Paton lines) may develop, especially

temporally .

• Macular fan: in younger patients small vesicles may form in the

superficial retina, converging on the fovea in a fan shape with the apex

at the fovea; this is not to be confused with a macular star, composed of

exudates.

• Enlarged blind spot.


• Chronic

• VA is variable and the visual fields begin to constrict.

• Disc elevation; cotton wool spots and haemorrhages

are characteristically no longer present.

• Optociliary shunts and drusen-like crystalline

deposits (corpora amylacea) may be present on the

disc surface.

• • Atrophic (secondary optic atrophy )

• VA is severely impaired.

• The optic discs are grey–white, slightly elevated, with

few crossing blood vessels and indistinct margins.

Papilloedema Treatment

• Weight loss, including via bariatric surgery, can be

very effective and formal dietary intervention is

strongly recommended.

• Other options include acetazolamide, furosemide,

digoxin and analgesia, and in unresponsive cases

optic nerve fenestration, lumboperitoneal shunting

and transverse dural sinus stenting.

• Steroids are controversial, but a short course is

sometimes used in severe papilloedema.

• Intravenous mannitol or a lumbar puncture are

usually reserved for acute severe exacerbations.

idiopathic

intracranial hypertension (IIH)

• modified Dandy criteria should be met for the

diagnosis of pseudotumor cerebri or IIH . The

patient should first demonstrate the signs and

symptoms of increased intracranial pressure.

Headache, transient visual obscurations, pulse-

synchronous tinnitus, papilledema with associated

visual loss, and diplopia due to sixth nerve palsies

are the common presenting symptoms and signs.

Idiopathic intracranial hypertension

• there should be an absence of localized findings on

neurological examination except for the “false

localizing” sixth nerve palsies. Neuroimaging should

reveal the absence of deformity, displacement, or

obstruction of the ventricular system. We like to use

magnetic resonance imaging (MRI) and magnetic

resonance venography (MRV) to look for additional

support for the presence of intracranial hypertension.

Findings characteristic of increased intracranial

pressure on MRI are empty sella, smooth-walled venous

stenoses of the lateral sinuses (on MRV), orbital

findings related to the unfolding of the nerve sheath,

and enhancement of the optic disc.

Idiopathic intracranial

hypertension MANAGEMENT

• I generally treat all patients with a low-sodium weight

management program. Patients usually improve with

weight loss of 5% to 10% body weight. Much more

weight loss is usually not sustainable and does not

appear to be necessary for IIH remission. Weight loss

may be all our patient needs, since there is no visual

loss with perimetric examination except for enlarged

blind spots. However, if her symptoms of intracranial

hypertension (eg, severe headache) were interfering

with her activities of daily living, I would start

acetazolamide in 2 divided doses, then gradually

escalating doses to 1 to 2 g per day.

• Diuretics can be used if the patient cannot tolerate

acetazolamide.

Idiopathic intracranial

hypertension MANAGEMENT

• The frequency of follow-up depends mostly on the risk

of visual loss. The 2 most important factors here are

amount of visual loss present and the degree of optic

disc edema. If the risk of further visual loss is low; the

usual revisit time after diagnosis is 1 to 2 months. I

would have this patient back in 2 months and, if she is

doing well, again in 4 months. Since IIH can be a

lifelong disease (like arterial hypertension), I follow

patients who are in remission every 1 to 2 years. The

• key features in following a patient are the change in

weight, change in symptoms, perimetry results, and

papilledema grade .

Summary

• IIH is a diagnosis of exclusion (modified Dandy

criteria).

• The typical patient with IIH is an overweight young

female; more aggressive evaluation for possible

etiologies should be considered in thin patients, men,

and the elderly.

• Medical treatment with weight loss and acetazolamide

are the first lines of therapy.

• Surgical treatment (optic nerve sheath fenestration or

shunting procedures) is reserved for patients with

progressive disease who fail maximal medical therapy.

MYASTHENIA GRAVIS

MYASTHENIA GRAVIS

• A 68-year-old woman presents with complaints of

droopy upper lids over the past few weeks.

• Sometimes one lid or the other might even close

completely. She has also noticed double vision, which

comes and goes.

• Since the majority of patients with myasthenia gravis

present with involvement of the lids and extraocular

muscles, the ophthalmologist is often the first

physician to make this diagnosis, usually based on key

history and clinical findings in the office. These reveal

a typically variable clinical picture that is modulated by

rest and fatigue; they also help establish localization

distal to the brainstem and cranial nerves.

MYASTHENIA GRAVIS

• key questions that address typical characteristics of

myasthenia—namely improvement with rest,

fatigability, and variability.

• The one question that I find most useful, and that

addresses the effect of rest, is whether the ptosis or

diplopia is present upon first awakening. Most patients

with myasthenic ptosis report that the lids are virtually

normal or much improved first thing after sleep.

Similarly, a report by a patient with diplopia of little or

no double vision upon awakening strongly suggests

myasthenia and reflects improvement from a tropia to a

phoria during sleep. This is in contrast to other causes

of diplopia where overnight ocular dissociation leads to

a tropia upon awakening with improvement afterward.

Key Physical Findings

• Pupils

• The pupils are not clinically affected by myasthenia gravis.

There should be no pupillary dilation or Horner syndrome.

• Ptosis

• There are several lid findings suggestive of myasthenia

gravis. Bilateral ptosis is common in myasthenia but rare in

brainstem or cranial nerve disorders. However, the bilateral

nature of the ptosis may be masked by the effect of

Hering’s law, in which the effort to open the more ptotic lid

brings the less ptotic lid into a normal or even a retracted

position. In apparently unilateral ptosis, lift the ptotic lid

and observe whether the “normal” (or retracted) lid

becomes ptotic .

Key Physical Findings

• Motility

• The presence of bilateral limitation of eye movement is very

helpful since in myasthenia both eyes are commonly involved ,

whereas bilateral involvement would be most unlikely in

brainstem or cranial nerve lesions. A motility pattern appearing

to be an isolated unilateral cranial neuropathy or internuclear

ophthalmoplegia may occur in myasthenia. However, it is

uncommon for myasthenia gravis to mimic these patterns without

other findings, such as ptosis or orbicularis weakness.

• Orbicularis

• You should test orbicularis function in all patients with ptosis or

motility problems. The orbicularis is weak in most myasthenic

patients , often visibly fatiguing with continued testing. The

presence of orbicularis weakness in a patient with ptosis and

motility abnormalities indicates a localization that cannot be

explained by a brainstem or cranial nerve lesion.

Management

• If additional symptoms suggest generalized

myasthenia gravis or if the isolated ocular

symptoms are of recent onset, you should

refer to a neuromuscular specialist in a

timely manner. I warn the patient that if

problems with breathing or swallowing

develop in the meantime, an urgent visit to

an emergency department would be in order.

myasthenia gravis

MANAGEMENT

• I usually defer to neuromuscular specialist to begin

a trial of pyridostigmine, then I see the patient

again after a few weeks. If patient has isolated

ocular myasthenia gravis and pyridostigmine has

not been fully effective, I add prednisone since this

is usually more effective for the ocular signs and

may decrease the rate of generalization. I usually

start at 1 mg/kg per day for 2 weeks, followed by

tapering. This results in remission for some

patients, but others need a maintenance alternate-

day dose.

Summary

• Clues that make myasthenia a consideration in a

patient with ptosis, diplopia, or both include the

following:

• Effect of rest

• Symptoms absent upon awakening

• Ptosis improves after office rest/ice test

• Fatigable ptosis

• Variable symptoms and findings

• Bilateral findings not mapping to cranial nerves

• Orbicularis weakness

THANK

YOU

DR DINESH

DR SONALEE

Health & Medicine

Neuro ophthalmology 2016