THIRD NERVE PALSY

Prepared by: Anis Suzanna binti Mohamad

Optometrist

What is third nerve palsy? a condition which leads to a wide

impairment of motor function, as this innervates most of the muscles of the eyes.

Aetiologies Types of 3rd

palsyCommon condition(s)

Congenital The palsy is usually incomplete, unilateral and without ptosis, the pupil is spared.

Acquired Microvascular (DM,HPT,atherosclerosis)

>45years old, pupil sparing, rare in children.

Compression (tumor, aneurysms)

The condition usually painful, with ptosis and pupil involvement.

Trauma Pupil involvement

Migrainous The condition occurs upon resolution of a headache, usually involving the pupil.

Infectious Viral illness, bacterial meningitis, or immunizations

Source: Essentials of clinical binocular vision by Erik M. Weissberg

1.Patient profile: Referred by: Ms. E Malay Female 18 years old File no: 5108 Date: 9/2/04

Referred from ophthalmologist at Hospital Tuanku Fauziah, Kangar for squint assessment.

Patient has RE optic neuropathy secondary to trauma, RE exotropia and LE high myope.

2. Presenting signs and symptomsSymptom RE exotropia after accident 14 years ago.

Diplopia appreciated.

Age of onset 11 years old

Mode of onset Accident

Medical or birth

history

Nil

Family history Nil

Previous

treatment

Glasses for high myopia

3. Clinical findings:Current Rx

Distance VA

Near VA

RE: -3.00Ds LE: -5.00Ds

(3/60) (6/6)

Hirschberg

Unil Cover test

(∞)

Unil Cover test

(Near)

~15° exo

RE exotropia with diplopia

RE exotropia with diplopia

Ocular MotilityRSR++

RIR-

‘A’ pattern exo

Vergence

System

Horizontal

vergence

Vertical

Vergence

35/40ΔBI

Exo

50ΔBI

Near: (RE) 35BI & 2BD

Distance: (RE) 35BI & 2BD (RE

hypertropia)

Post-op diplopia

test

Near: Patient see single with 35ΔBI

Distance: Do not appreciate diplopia when

overcorrect until 50ΔBI

4. Diagnosis: Secondary right eye exotropia due to

trauma.

5. Management plan5. Management planSuggest surgery for cosmetic reason.Suggest for unilateral recess and resect.◦7.0mm RLR recess ◦6mm RMR resect.Attached a referral letter to

ophthalmologist at Hospital Tuanku Fauziah, Kangar.

Discussion

Anatomy of third cranial nerve

Anatomic Basis of Neurologic Diagnosis by Cary D. Alberstone

Criteria for ocular motor palsy

Source: Essentials of clinical binocular vision by Erik M. Weissberg

Classification Involved

muscle(s)

Ocular motility Restricted version Ptosis

Complete

(superior and

inferior division)

MR,SR,IR,IO,

levator

Exotropia,

hypotropia,

intorted

Adduction, elevation,

depression

Yes

Superior division

only

SR, levator Hypotropia Elevation Yes

Inferior division

only

MR,IR,IO Exotropia,

hypertropia,

intorted

Adduction, elevation,

depression

No

Isolated muscle MR Exotropia Adduction No

Isolated muscle SR Hypotropia Elevation when adducted No

Isolated muscle IR Hypertropia Depression when

abduction

No

Isolated muscle IO Hypotropia Elevation when

adduction

NoTable of classification, involved muscle and associated signs of third cranial nerve palsy.

Source: Essentials of clinical binocular vision by Erik M. Weissberg

Limitations

Incomplete history taking Clinical findings

Refinement on refractive error.Basic squint assessment hirschberg test, unilateral

cover test, ocular motility, vergence system and post-op diplopia test.

No external observation recorded.Hess chart Post-op diplopia test

LR recession & MR resection in XT

XT (pD) LR recess MR resect

15 4.00 mm 3.00 mm

20 4.00 mm 4.00 mm

25 6.00 mm 4.50 mm

30 6.50 mm 5.50 mm

35 7.50 mm 5.50 mm

• Suggest surgery for cosmetic reason.

• Suggest for unilateral recess and resect.

•7.0mm RLR recess and 6mm RMR resect.

References:I. Millodot, M. 2000. Dictionary of Optometry and Visual

Science. Oxford: Butterworth-Heinemann Ltd.

II. Erik M. 2004. Essentials of clinical binocular vision. Elsevier: Butterworth-Heinemann Ltd.

III. Alec M. Ansons. 2001. Diagnosis and management of ocular motility disorders.Blackwell Science Ltd.

IV. Bruce Evans, David Pickwell. 2004. Pickwell’s binocular vision anomalies: investigation and treatment. Elsevier: Butterworth-Heinemann Ltd.

V. Burian & von Noorden. 2000. Burian von-Noorden’s Binocular Vision and ocular motility: theory and management of strabismus. Elsevier: Butterworth-Heinemann Ltd.

VI. Cary D. Alberstone. 2000. Anatomic Basis of Neurologic Diagnosis. Elsevier: Butterworth-Heinemann Ltd.