updated frohman 2014 cmsc vision talk · 6/5/2014 5 cranial nerve ii- optic nerve assessment...

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Common visual symptoms and findings in MS: Clues and Identification

Teresa C Frohman, PA-C, MSCSNeuro-ophthalmology Research Manager, UT Southwestern Medical Center at Dallas

Professor Biomedical Engineering, University of Texas Dallas

COMMON COMPLAINTS

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Blurry Vision

Corrected with

Refraction?

YES NO

Refractive Error

Keep Looking

IN MS : ON, Diplopia,

Nystagmus

Most Common Visual Issues Encountered in MS patients

• Optic Neuritis• Diplopia

• Nystagmus

result from damage to the optic nerve or from an incoordination in the eye muscles or damage to a part of the oculomotor pathway or apparatus

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Optic Neuritis Workup

‘frosted glass’

Part of visual field missing

Pain +/-

Color desaturation

YES NO

Seeing double images

Or ‘jiggling’ No

Yes

Neuro-ophth exam

Humphrey’s

OCT

MRI

Fundoscopy

Work up for diplopia or nystagmus

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CRANIAL NERVE ANATOMY

There are 12 pairs of cranial nerves CN I Smell CN II Vision CN III, IV, VI Oculomotor CN V Trigeminal Sensorimotor

muscles of the Jaw CN VII Sensorimotor of the face CN VIII Hearing//vestibular CN IX, X, XII Mouth, esophagus,

oropharynx CN XI Cervical Spine and shoulder

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NEURO-OPHTHALMOLOGY EXAM

Visual Acuity

Color Vision

Afferent pupillary reaction- objective test of CNII function

Alternating flashlight test – afferent arc of pupillary light reflex pathway

Fundus exam

Visual Fields –confrontation at bedside

CRANIAL NERVE II: OPTIC

once the retinal ganglion cell axons leave the back of the eye they become myelinated behind the lamina cribosa ---and become the OPTIC NERVE

Optic nerves pass through the optic canals and converge at the optic chiasm They continue to the thalamus where they synapse

From there, the optic radiation fibers run to the visual cortexFunctions solely by carrying afferent impulses for vision

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CRANIAL NERVE II- OPTIC NERVE

Assessment Cranial nerve IIVisual Acuity – snellen chart

Visual Fields – confrontation

Fundoscopy

Pupillary light reflex

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Snellen Chart

Patient’s own glasses/contacts

Pinhole

Pinhole refraction is a rapid, efficient way to diagnose refractive errors, which are the most common cause of blurred vision. However, with pinhole refraction, best correction is usually to only about 20/30, not 20/20.


Assessment Cranial nerve II Visual Acuity – Snellen chart

Visual Fields

Fundoscopy


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Test by confrontationAssess superior, temporal, inferior and nasal fields

Humphrey’s Automated Perimetry

Damage to an optic nerve results in blindness in the eye serviced by that nerve

Damage to visual pathways distal to the optic chiasm results in partial visual losses.

Visual defects are called anopsias.

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VISUAL FIELD DEFECTS

1. Optic nerve

ipsilateral (same side) blind eye

2. Chiasmatic (pituitary tumors classically)

lateral half of both eyes gone

3. Optic tract

opposite half of visual field gone

4. & 5. Distal to geniculate ganglion of thalamus:

homonymous superior field (4) or homonymous inferior field (5) defect

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Visual fields

1.

2.

3.

Location of lesion:

1

2 3

4

5


Assessment Cranial nerve II Visual Acuity – snellen chart

Visual Fields

Fundoscopy Neuro-retinal rim-axons of RGC

Orange pink w/central cup

Axons die--white=pallor


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Normal Optic disc pallor

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Assessment Cranial nerve II Visual Acuity – snellen chart

Visual Fields

Fundoscopy


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Direct light reflexConsensual light reflexSwinging flashlight testAPD, afferent pupillary

defect

PUPILLARY LIGHT REFLEX

LEFT RELATIVE AFFERENT PUPILLARY DEFECT

Normal Left Optic Neuritis/Neuropathy

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OPTIC NEURITIS WORKUP Typically vision returns within a few weeks

to months

Many affect color vision even if acuity returns to 20/20

Can cause a large ‘blind spot’ in center of visual field

OCT will show thinner RNFL-

OCT on the Cirrus OCT evaluating peripapillary RNFL thickness shows decreased average thickness, with thinning predominantly of the temporal aspects of both optic nerve heads.

MRI -fat suppressed T1 weighted post gadolinium images.


‘frosted glass’


Pain +/-

Color desaturation

YES NO



Yes

Humphrey’s

OCT

MRI

Fundoscopy


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QUESTION TO START WITH

Is it Unilateral or BilateralDiplopia- caused by two images

No double vision with monocular viewing = lens or cornea problem

DIPLOPIA Diplopia (double vision), the experience of seeing two of

everything, is caused by weakening or incoordination of eye muscles or supranuclear leasion (skew deviation)

Common causes of Diplopia in MS INO

6th Nerve Palsy > 3rd nerve palsy > 4th nerve palsy

Skew deviation

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EYE MOVEMENTS

Controlled by CN III, IV, & VICN III

superior rectus inferior rectusmedial rectus inferior oblique

CN IV superior oblique

CN VI lateral rectus

Superior = “in crowd” = intortersInferior = “out crowd”= extorters

DIPLOPIA

Common causes of Diplopia in MS

INO

6th > 3rd > 4th Nerve Palsy

Skew deviation

Internuclear OphthalmoplegiaINO•adduction slowing with or without limitaton•Most common oculomotor abn in MS•Lesion of MLF –ipsilateral•Can cause diplopia when making saccades

away from side of lesion

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CN III, OCULOMOTOR

Innervates SR, IR, MR, IO

Elevates eyelid, levator palpebrae

Constricts pupil via sphincter muscles of iris

Contraction of ciliary muscle reduces tension on lens allowing focusing on closer objects

A common treatment for this is to

place an eye patch on the stronger

(dominant) eye in order to strengthen

the weaker muscles of the affected eye.

CRANIAL NERVE IV: TROCHLEAR

Fibers emerge from the dorsal midbrain and enter the orbits via the superior orbital fissures; innervate the superior oblique muscle

Primarily a motor nerve that directs the eyeball

Fourth Nerve PalsyDouble vision following trochlear nerve palsy is most prominent when the patient adducts their eye, such as when walking downstairs or reading a book. Patients may also hold their head in a tilited position to compensate.

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CRANIAL NERVE VI: ABDUCENS Sixth Nerve Palsy

Sixth nerve palsy results in a patient unable to abduct the eye. It is also a false localizing sign in raised intracranial pressure or basal skull fracture. The long course of the abducens nerve leaves it vulnerable to pressure changes.

In abducens nerve paralysis, the eye

cannot be moved laterally; at rest,

the affected eyeball turns medially

(internal strabismus), giving a person a

'cross-eyed' condition.

.

IS IT HORIZONTAL OR VERTICAL

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4TH NERVE VS SKEW DEVIATION

4TH NERVE PALSY 1. Hypertropia in primary position

2. Incomitant: hypertropia worse on gaze to opposite side acutely; may become comitant with time

3. Hypertropia worse on ipsilateral head tilt

4. Compensatory head tilt contralateral to the hypertropic eye

5. Excyclotorsion of the hypertropic eye

6. Usually no other neurologic signs (unless caused by brain trauma or lesions in brainstem)

SKEW DEVIATION 1. Hypertropia in primary position

2. Incomitant, comitant, or alternating

3. Hypertropia may or may not change with head tilt

4. Pathologic head tilt contralateral to the hypertropic eye

5. Incyclotorsion of the hypertropic eye if present (and excyclotorsion of the hypotropic eye)

6. Usually has other neurologic signs (eg, gaze-evoked nystagmus, gaze palsy, dysarthria, ataxia, hemiplegia)


‘frosted glass’


Pain +/-

Color desaturation

YES NO



Yes

Humphrey’s

OCT

MRI

Fundoscopy


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NYSTAGMUSNystagmus: Upon examination, the physician may detect a

rhythmic jerkiness or bounce in one or both eyes. This relatively common visual finding in MS is nystagmus. Nystagmus does not always cause symptoms of which the person is aware.

Mononcular Occluded fundoscopy

Sometimes nystagmus can accompany INO, but it can also be due to any type of MS attack in the vestibular or inner ear part of the brainstem, or to the cerebellum, which is our coordination center.

Final Thoughts

In summary, vision can be impaired by MS in many different ways.

People with MS who experience visual problems may benefit from an evaluation by both a neurologist and an ophthalmologist, or a neuro-ophthalmologist if one is available.

Uhthoff’s Phenomenon- esp: ON and INO

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THANK YOU

updated frohman 2014 cmsc vision talk · 6/5/2014 5 cranial nerve ii- optic nerve assessment...

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