Third nerve palsy is a condition that leads to impairment of motor function as the third cranial nerve innervates most eye muscles. It can be congenital or acquired through conditions like diabetes, hypertension, tumors or trauma. Acquired third nerve palsy often involves patients over 45 and can cause ptosis and pupil involvement while congenital palsy is usually unilateral and incomplete without ptosis. The document discusses a case study of a 18-year old female referred for assessment of right eye exotropia secondary to trauma as a child. Her examination findings and diagnosis of right eye exotropia are presented along with a management plan of unilateral eye muscle surgery.

1. THIRD NERVE PALSY
Prepared by:
Anis Suzanna binti Mohamad
Optometrist

2. 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.

3. Aetiologies
Types of 3rd
palsy
Common 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

4. 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.

5. 2. Presenting signs and symptoms
Symptom 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

6. 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

7. Ocular Motility
RSR++
RIR-
‘A’ pattern exo
Vergence
System
Horizontal
vergence
Vertical
Vergence
35/40Δ
BI
Exo
50Δ
BI
Near: (RE) 35BI & 2BD
Distance: (RE) 35BI & 2BD (RE
hypertropia)
Post-op diplopia
test
Near: Patient see single with 35Δ
BI
Distance: Do not appreciate diplopia when
overcorrect until 50Δ
BI

8. 4. Diagnosis:
 Secondary right eye exotropia due to
trauma.
5. Management plan5. Management plan
Suggest 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.

9. Discussion

10. Anatomy of third cranial nerve

11. Anatomic Basis of Neurologic Diagnosis by Cary D. Alberstone

13. Criteria for ocular motor palsy
Source: Essentials of clinical binocular vision by Erik M. Weissberg

14. 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
No
Table of classification, involved muscle and associated signs of third cranial nerve palsy.
Source: Essentials of clinical binocular vision by Erik M. Weissberg

15. 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

16. 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.

17. 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