Duane syndrome
Duane syndrome is a congenital type of
strabismus characterized by Limitation of
abduction ( Duane type I ), limitation of
adduction ( Duane type II ) or limitation of
both abduction and adduction ( Duane type III ).
Duane patient may be orthotropic, esotropic in
type I, exotropic in type II, or any other form
in type III.The other characteristic feature of
Duane syndrome is retraction of the globe on
attempt adduction with consequent narrowing of the palpebral
fissure, the name (Duane Retraction Syndrome )
is also used in the literature. Face turn is a
common finding in Duane patients, the face turns towards the
direction where the eye can not go. Another
feature of Duane Syndrome is the up shot or down
shot of the affected eye on adduction. The
syndrome was named after Alexander Duane who
discussed the disorder in 1905.
Duane syndrome can be associated with other
congenital anomalies including cervical spine abnormalities, Klippel-Feil syndrome, Goldenhar syndrome,
heterochromia, and congenital deafness.
Duane syndrome is caused by miswiring of the
eye muscles where the opposing muscles ( the
medial rectus and the lateral rectus ) become
innervated by the same nerve ( 3rd cranial nerve
). Thus, on attempted
abduction, stimulation of the lateral rectus via
the 3rd nerve will be accompanied by
stimulation of the opposing medial rectus via
the same nerve. Thus, co-contraction of the muscles
takes place, limiting the amount of movement
achievable and also resulting in retraction of
the globe. Co-contraction of the medial and
lateral recti during adduction may make the globe to slip up or
down under the tight lateral rectus producing
the up and down shoots.
Many patients with Duane Syndrome remain symptom
free and able to maintain binocularity with only
a slight face turn.
Duane syndrome cannot be cured, as the
miswiring cannot be corrected, no expectation
that surgery will result in any increase in the
range of the limited eye movement. Surgical
intervention has only been indicated when
there is :
-
·
Uncomfortable head posture
-
·
Esotrpia or exotropia in the primary position
-
·
Up or down shoots on adduction
-
·
Disfiguring narrowing
during adduction
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