Ophalmology pdf 3,4,6 cranial nerve pdf share

Optha

2. Occulomotornerve
(3
RD
NERVE)
Introduction:

7. Causes

Common in adults:
e Microvascular (diabetes, hypertension, atherosclerosis)
e Compression (tumor, aneurysms)
e Trauma
e Congenital
common in children

e Migrainous

e Infectious

10. Diagnosis

y Diplopia: Typically both horizontal and vertical, eliminated with monocular occlusion, and
may not be reported if ptosis is occluding the eye or if image separation is exceedingly

large
Y Ptosis: Complete, incomplete, or absent due to aberrant regeneration

Ÿ Pain: May or may not be present

12. Treatment:

・ Treatment initially involves medical management of systemic predisposing

factors and conservative measures

・ Surgical intervention in non resolving oculomotor nerve palsy.

14. Trochlear nerve
(4
th
nerve)

15. Introduction

FUNCTIONAL COMPONENTS

ㆍ SOMATIC EFFERENT-concerned with
movement of eye ball through SO.

ㆍ GENERAL SOMATIC AFFERENT-carries
proprioceptive impulses from SO which are
relayed in the mesencephalic nucleus of 5%
nerve.

19. CAUSES

OTrauma

QVascular, for example hypertension.
U Diabetes

Q Space-occupying lesions

DOther

20. Diagnosis

Ipsilateral hypertropia, excycloduction,

V. Esodeviation

The torsional deviation increases in lateral gaze to one
side, while the vertical deviation increases on opposite
lateral gaze.

For example, weakness of the left superior oblique results
in — VD, which increases on right gaze and excyclotropia
which increases on left gaze

Combined vertical and torsional diplopia, increasing in
downgaze

21. Treatment

-In recent cases ,investigation and wait till
6 months if recovery occur
«Prism for small vertical deviations

«Surgery for large decompensating vertical
deviation

23. Abducens nerve
(6
th
nerve )

24. Introduction

The sixth cranial nerve is a somatic efferent nerve that
innervates ipsilateral lateral rectus (LR) muscle to elicit eye
abduction.

Effector organ : LR muscle

Action: Eye abduction

Also called as abducens nerve or abducent nerve or CNVI.

Function:
Solely to innervate the lateral rectus muscle and abduct the eye.

26. 6" nerve palsy

0 What?:

RUNSd ability of the affected eye to turn out (abduct) due to 6" nerve
lesion.

“Classified under neurogenic-cause of incomitant strabimus
0 Itcan be congenital (rare) or acquired (common).
" Can be unilateral or bilateral 6" nerve palsy.

28. Causes

Lesions can attect any part ot the nerve’s pathway.

Usually due to direct damage of the sixth cranial nerve, encephalon
nuclei or less frequently diffuse axonal damage.

(Hamidon et al. 2012)

It can be congenital (rare) or acquired (common).

Identifying the causative factor is important for further
management.

The four most common causes were idiopathic (26%),
hypertension alone (19%), coexistent diabetes and
hypertension (12%), and trauma (12%).

29. Diagnosis

+ D>N
« Increase with gaze
at affected side

+ In the affected eye
+ Normal adduction

+ Worse at affected
side & distance

+ Towards affected
side
+ To avoid diplopia

31. Treatment

Se

a.

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32. Extra occular muscle surgery

+ Indicated if longstanding esotropia

* Considered when the deviation has been stable for 6 months

・ May include a combined medial rectus recession and lateral rectus
resection on the affected side

Muscle Recession Procedure Muscle Resection Procedure

Original position Extraocular muscle

Move - Detach-
Reattach Remove-
posteriorly Reattach

33. Thankyou