Ocular motility

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I- Introduction :

ocular motility disorders include :

  • paralytic disorders : adults
  • functional disorders : child

II- anatomy :

  • each eye features 3 pairs of muscles
  • these 6 muscles work together to turn the eyes to lead in the same direction
  • c’is mainly thanks to these eye muscles that we can read without difficulty
  • the levator muscle of the upper eyelid

III- anatomoohvsioloaiaue Reminder :

  • Eye movements are around 3 axes : vertical, horizontal, oblique

Goals :

  • Change d’image :
  • Saccades : very fast movements (20 at 40 ms) eyes, for positioning the fovea on the word reading
  • Stably maintain an image on the macula :
  • eye tracking : slow eye movements
  • Convergence : lets see close

1- extrinsic oculomotor :

6 controlled by muscles 3 nerves :
→ Motor nerve oculomotor (III) :

  • Muscle domestic law
  • Muscle top right
  • Muscles lower right
  • Muscle petit oblique
  • Levator muscle of the eyelid

→ pathetic Nerve (IV) : large oblique muscle
→ Abducens (WE) : muscle lateral rectus

laws eye movements :

o Sherrington : couple d’antagonist, when a muscle contracts l’other relaxes

Hering : in binocular movement, l’nerve impulse is sent in an equivalent amount to the muscles performing the same movement

2- intrinsic oculomotricity :

Traction of the’iris depends on two antagonistic smooth muscles
– sphincter of the’iris (constrictor’iris) : contingent para sympathetic III
– dilator muscle’iris : sympathetically
L’Accommodation : contingent para sympathetic III

IV- Clinique :

diplopie : double d visual perception’a unique object

  • Diplopie monoculaire : cause OPH (iridectomie)
  • binocular diplopia : oculomotor palsy (stones, nerves, muscles oculomoteurs) and strabismus

Clinique 1 : Organic TMO :

Paralysis oculomotor :

1- functional signs :

  • diplopie : the sensation of seeing double
  • wrong direction : an erroneous assessment of the situation of objects in the’space
  • strabismus

2- objective signs :

  • vicious attitude of the head
  • ocular deviation
  • limitation of’excursion of the movements of the globe in the field of’paralyzed muscle action

→ TDD : nerve palsy : complete, it leads to :

  • un ptosis
  • a vertical or oblique diplopia
  • a divergent strabismus
  • l’inability to move the’eye in, up and down
  • mydriasis / paralysis of the’accommodation

=> paralysis is often incomplete or partial extrinsic damage giving rise to either an isolated intrinsic reached

3- Etiologies of oculomotor palsy :

a- POM birth
b- traumatic POM : cranial trauma, orbital trauma
c- Affection of the’orbit and neighborhood conditions :
– acute inflammation – tumors of the’orbital apex – tumors of the ENT reached by the cavernous sinus
d- General infectious diseases and intoxications :
– typhoid, scarlatine – ophthalmic zoster – lead poisoning
e- Diabetes, avitaminose
f- Nervous System Diseases :
– THIS – SEP, neurosyphilis – vascular syndrome : hemorrhagic stroke
g- Retinal migraine
h- paralysis myogenic : myasthénie, orbital myositis

4- Treatment of paralysis oculomotor :

– etiological – orthoptics – surgical : stage sequelae

Clinique 2 : Functional TMO

strabismus :

  • 4 at 5% of the general population
  • 58% present amblyopia

A- esotropia : esotropie

1/ esotropie accommodatives pures :

  • old 2 at 3 years (accommodation)
  • hyperopia uncorrected

2/ esotropie non accommodatives :

  • usually congenital
  • are not related to the’hyperopia
  • the correction does not correct the deviation
  • poor prognosis because binocular vision’is not elaborated

B- Strabismus divergent or exotropia :

1/ Exotropies accommodatives :

  • c’is strabismus diverge from myopia or l’insufficient convergence
  • in myopic l’accommodation is disturbed, and the convergence
  • optical correction corrects’exotropie

2/ secondary exotropia : l’natural evolution d’amblyopia

Note : "Vertical strabismus"

  • primary : by hyper-action of the oblique muscles "congenital strabismus"
  • secondary : a horizontal "late phase" element

→ Treatment of functional strabismus :

– treatment of l’amblyopie+++++

a. trt of l’sensory element : optical trt’ametropia and orthoptic trt

b. trt of l’driving element

Dr Degdeg course – Faculty of Constantine