Strabismus - Fundamentals of Clinical Ophthalmology.pdf

THERAPY OF STRABISMUS
because of increased risk of inducing an
iatrogenic Brown syndrome.
(a)
Transposition
Transposition in a vertical direction of the
rectus muscles when overaction of oblique
muscles is absent is the commonest method
of management of A and V syndromes.
In some cases of isolated complete third nerve
palsy, the intact superior oblique muscle with its
innervation can be used to provide balancing
tone to the lateral rectus, producing improved
horizontal alignment.
Vertical muscle surgery in A and V
patterns of movements
In congenital esotropia and congenital
exotropia, particularly intermittent exotropia,
the surgeon’s decisions should include whether
or not to correct the associated A or V pattern.
A and V patterns of movement may be
responsible for variability of strabismus.
(b)
Figure 7.9 Surgical approach to the inferior oblique
insertion. (a) Exposure of the inferior oblique,
(b) sharp dissection of the insertion of the inferior
oblique muscle prior to recession
Strengthening procedures
Resection +/− advancement
This is the commonest form of strengthening
procedure and is commonly performed on the
horizontal rectus muscles.
Plication of muscle or its tendon
This procedure is not commonly performed.
Plication of the tendon of the superior oblique is
most effective in cases of a congenitally lax
superior oblique tendon. Caution should be
exercised in traumatic fourth nerve palsies
Scenarios
A and V pattern and evidence of marked
overaction of the oblique muscles The
underlying principle is to weaken the overacting
muscle. In A exotropia with marked superior
oblique overaction, correct with a posterior
superior oblique tenotomy leaving the anterior
part of the tendon, which controls torsion.
Posterior superior oblique tenotomies can
collapse the A pattern by as much as 15–20º.
In V exotropia, with marked inferior oblique
overaction, correct with inferior oblique muscle
weakening procedure.
A and V pattern and no evidence of
oblique muscle overaction The principle is
to alter the line of action of the horizontal
muscles by vertical shift. Correct by transposition
of the horizontal muscles, either moving the
medial rectus muscles to the apex of the A
or the V or, in the case of lateral rectus muscles,
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