( Monocular
elevation deficiency )
Palsy
of both elevator muscles ( SR & IO ) is a rare
anomaly of ocular motility. On F
ixation
with the sound eye, the paretic eye will take a
hypotropic position and the upper lid will be
slightly ptotic. On Fixation with the paretic
eye, the ptosis may disappear, here the name
pseudoptosis, where usually, no levator surgery
is needed . There is
limitation of elevation of the paretic eye from
any position of gaze, in Brown syndrome the
limitation of elevation is seen only during
adduction. Bell’s phenomenon is
usually preserved. The ductions of the paretic
eye are normal in all other positions of gaze.
The chin is usually elevated. This anomaly is
often congenital.
The
differential diagnosis
of a double elevator
palsy are :
1. blow-out
fracture of the orbital floor.
2. Congenital
fibrosis of the EOM.
3. Endocrine myopathy.
4. Anomalous insertion of
the inferior rectus muscle.
5. Brown Syndrome
A
positive forced duction test and increased
intraocular pressure in upward gaze may
distinguish these conditions from double
elevator palsy.
Surgery is indicated only
when there is hypotropia in primary position or
chin elevation or both. The aim of surgery is to
restore single binocular vision in primary
position.
Knapp introduced vertical
transposition of the horizontal rectus muscles
to the medial and lateral edge of the superior
rectus muscle with or without recession of the
IR.
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